CI: test the installed Windows app's PC libraries, after the installer check

Running the bundled Python against win-unpacked wrote __pycache__ into
the copy the installer check compares with, so the check failed. The
test now runs after that check, on the installed app, without writing
bytecode.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.github/workflows/pc-host.yml

@@ -0,0 +1,53 @@
+name: PC host libraries
+# PC in the headset (Experimental). The Windows job builds the native adapter
+# and runs the real-encoder protocol tests; the installer's own bundle is
+# tested in release.yml. The Linux adapter from PR #38 isn't shipped or offered
+# in the app, but shares capture.c and controller.c, so it's still built here.
+# These builds add the GPL x264 encoder for headless tests only: they're never
+# uploaded or shipped.
+on:
+  pull_request:
+    paths: ["desktop/**", "ui/**", "tests/**", "scripts/macview-bench.py", ".github/workflows/pc-host.yml"]
+  workflow_dispatch:
+jobs:
+  linux:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, ubuntu-24.04-arm]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Native libraries
+        run: |
+          sudo apt-get update -qq
+          sudo apt-get install -y libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev libglib2.0-dev gstreamer1.0-plugins-base gstreamer1.0-plugins-good gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly gstreamer1.0-pipewire libpipewire-0.3-modules libspa-0.2-modules
+          python3 desktop/build.py --with-x264
+      - name: Tests (real x264, fake capture consent/input)
+        env:
+          FRAME_PC_REQUIRE_NATIVE: "1"
+          FRAME_PC_REQUIRE_X264: "1"
+        run: python3 -m unittest discover -s tests -p 'test_pc*.py' -v
+  windows:
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: msys2/setup-msys2@v2
+        with:
+          msystem: UCRT64
+          update: true
+      # A mirror's HTTP 429 once failed this install (2026-10-24): retry, so a
+      # flaky mirror can't break a release build.
+      - name: MSYS2 packages for the PC host
+        shell: msys2 {0}
+        run: |
+          for attempt in 1 2 3; do
+            pacman -S --needed --noconfirm mingw-w64-ucrt-x86_64-gcc mingw-w64-ucrt-x86_64-pkgconf mingw-w64-ucrt-x86_64-python mingw-w64-ucrt-x86_64-gstreamer mingw-w64-ucrt-x86_64-gst-plugins-base mingw-w64-ucrt-x86_64-gst-plugins-good mingw-w64-ucrt-x86_64-gst-plugins-bad mingw-w64-ucrt-x86_64-gst-plugins-ugly && exit 0
+            sleep $((attempt * 30))
+          done
+          exit 1
+      - name: Native build and tests (x264; WGC and MF need a desktop/GPU)
+        shell: msys2 {0}
+        run: |
+          python desktop/build.py --with-x264
+          FRAME_PC_REQUIRE_NATIVE=1 FRAME_PC_REQUIRE_X264=1 python -m unittest discover -s tests -p 'test_pc*.py' -v

.github/workflows/release.yml

@@ -3,14 +3,14 @@ name: release
 # Pushing a v* tag builds Frame Control for macOS, Windows and Linux and attaches
 # the installers to that tag's GitHub release (created as a draft if missing).
 # Pull requests that change how the installers are built (the Electron app, the
-# macOS helper it compiles, or this workflow) build the same installers as
+# Windows PC helper libraries, the macOS helper, or this workflow) build the same installers as
 # artifacts. ui/, scripts/, frame/ and apk-catalog/ are copied in as they are and
 # are tested by the checks workflow; run this one by hand to package them early.
 on:
   push:
     tags: ["v*"]
   pull_request:
-    paths: ["app/**", "mac/frame-mac-view/**", ".github/workflows/release.yml"]
+    paths: ["app/**", "desktop/**", "mac/frame-mac-view/**", ".github/workflows/release.yml"]
   workflow_dispatch:
 
 # A newer push to the same pull request supersedes a build still in progress.
@@ -75,6 +75,28 @@ jobs:
       - uses: actions/setup-node@v4
         with:
           node-version: "24"
+      # PC in the headset (Experimental, Windows only): our capture adapter and
+      # the GStreamer libraries it uses, bundled into resources/desktop/bundle.
+      - uses: msys2/setup-msys2@v2
+        if: runner.os == 'Windows'
+        with:
+          msystem: UCRT64
+          update: true
+      # A mirror's HTTP 429 once failed this install (2026-10-24): retry, so a
+      # flaky mirror can't break a release build.
+      - name: MSYS2 packages for the PC host
+        if: runner.os == 'Windows'
+        shell: msys2 {0}
+        run: |
+          for attempt in 1 2 3; do
+            pacman -S --needed --noconfirm mingw-w64-ucrt-x86_64-gcc mingw-w64-ucrt-x86_64-pkgconf mingw-w64-ucrt-x86_64-python mingw-w64-ucrt-x86_64-gstreamer mingw-w64-ucrt-x86_64-gst-plugins-base mingw-w64-ucrt-x86_64-gst-plugins-good mingw-w64-ucrt-x86_64-gst-plugins-bad mingw-w64-ucrt-x86_64-gst-plugins-ugly && exit 0
+            sleep $((attempt * 30))
+          done
+          exit 1
+      - name: Windows PC streaming libraries
+        if: runner.os == 'Windows'
+        shell: msys2 {0}
+        run: python desktop/build.py --out app/build/desktop/win-x64
       - name: Build
         working-directory: app
         shell: bash
@@ -95,6 +117,19 @@ jobs:
           for ($i = 0; $i -lt 60 -and -not (Test-Path (Join-Path $installed 'Uninstall Frame Control.exe')); $i++) { Start-Sleep 2 }
           node app/build/check-resources.js (Join-Path $installed 'resources') app/dist/win-unpacked/resources
           if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+      # From the installed app, so this also proves the installer carries the
+      # libraries. After the check above, and without writing __pycache__,
+      # so it can't change what that check compares.
+      - name: Test the installed app's Python with the Windows PC libraries
+        if: runner.os == 'Windows'
+        shell: bash
+        env:
+          PYTHONDONTWRITEBYTECODE: "1"
+        run: |
+          resources="$(cygpath -u "$LOCALAPPDATA")/Programs/Frame Control/resources"
+          python="$resources/python/python.exe"
+          native="$(cygpath -w "$resources/desktop/bundle")"
+          FRAME_PC_NATIVE="$native" FRAME_PC_REQUIRE_NATIVE=1 FRAME_PC_INSTALLER_BUNDLE=1 "$python" -B -m unittest discover -s tests -p 'test_pc*.py' -v
       - name: Upload to the release
         if: startsWith(github.ref, 'refs/tags/')
         shell: bash

.gitignore

@@ -7,5 +7,15 @@ compat-db/.lakebed/
 tests/smoke/results/
 mac/bin/
 
+# Shared desktop streaming controller build products
+desktop/controller.dll
+desktop/controller.dylib
+desktop/controller.so
+desktop/*.obj
+desktop/*.lib
+desktop/*.exp
+desktop/bundle/
+app/build/desktop/
+
 # Downloaded at build time (frame/kdeconnect/fetch.py, app/build/fetch-deps.js)
 frame/kdeconnect/packages/

README.md

@@ -89,6 +89,14 @@ Install desktop apps like Moonlight or VLC, and set each Android app's resolutio
 **⚡ One-click tools**<br>
 SSH, SFTP, Steam Link, remote desktop, volume, sleep, restart and shut down.
 
+</td>
+</tr>
+<tr>
+<td colspan="2" valign="top">
+
+**💾 Backup and recovery**<br>
+Copy game saves, settings and Android app data to your computer, and restore them after a factory reset. Sign-in files and keys are never copied. A Return to Game Mode button helps when the headset is stuck in Desktop Mode. Not tested on a headset yet. [How it works](docs/backup-and-recovery.md).
+
 </td>
 </tr>
 </table>
@@ -218,6 +226,7 @@ Frame's software fits together, all checked against a real headset and labelled
 | [Sideloading Linux and Windows games](docs/sideloading.md) | A .zip, folder or .exe as a Steam Devkit Game, runtime detection |
 | [Install links for websites](docs/web-install.md) | `frame-control://install` links and manifests, the rules, a button to paste |
 | [VR comfort and HUD](docs/vr-utilities.md) · [Steam games](docs/steam-games.md) · [VR video](docs/vr-video.md) · [WebXR in Chromium](docs/webxr-chromium.md) | Installing and buying, watching VR180/360, the Chromium build |
+| [PC in the headset](docs/pc-in-headset.md) | Experimental, Windows only, off until you turn it on: your PC's windows and screens as panels in the Frame. Not yet tried on a real Windows desktop or headset |
 | [Mac in the headset](docs/mac-in-headset.md) | Mac windows and screens as panels in the Frame, with laser and keyboard input |
 | [VR mods and custom songs](docs/mods.md) | UEVR for Unreal games from Frame Control (install, play in VR, remove), the per-game table, Beat Saber blockers |
 | [SSH](docs/ssh.md) · [Streaming](docs/streaming.md) · [Files](docs/file-transfer.md) · [Panels](docs/panels.md) · [Tailscale](docs/tailscale.md) | Topic notes |

THIRD_PARTY_NOTICES.md

@@ -10,6 +10,8 @@ ship other people's software, unchanged, each under its own licence:
 | adb (Android SDK Platform-Tools) | Desktop apps (not Linux arm64) | Apache-2.0 and others | `NOTICE.txt` in the app's `tools` folder |
 | Mozilla's CA certificate list, as published by curl | Desktop apps | MPL-2.0 | https://curl.se/docs/caextract.html |
 | Electron | Desktop apps | MIT (Chromium: BSD-3-Clause and others) | `LICENSE` and `LICENSES.chromium.html` in the app |
+| GStreamer 1.x, a few of its plugins and the libraries they need, as [MSYS2](https://packages.msys2.org/) builds them | Windows app only, for the experimental [PC in the headset](docs/pc-in-headset.md) | LGPL-2.1-or-later and others (per package); the GPL x264 encoder is left out | `libraries.json` (exact package versions) and the `licenses` folder in the app's `desktop/bundle` folder |
 
 Frame Control starts KDE Connect and talks to it over its network protocol;
-it doesn't link to it or include its code.
+it doesn't link to it or include its code. On Windows, Frame Control's own
+`pc-host.dll` links to GStreamer dynamically; the libraries are unmodified.

app/package.json

@@ -198,7 +198,16 @@
         "zip"
       ],
       "icon": "build/icon.png",
-      "artifactName": "Frame-Control-win-${arch}.${ext}"
+      "artifactName": "Frame-Control-win-${arch}.${ext}",
+      "extraResources": [
+        {
+          "from": "build/desktop/${os}-${arch}",
+          "to": "desktop/bundle",
+          "filter": [
+            "**/*"
+          ]
+        }
+      ]
     },
     "nsis": {
       "oneClick": false,

app/preferences.js

@@ -1,7 +1,7 @@
 // Client choices live outside the local server's changing URL/origin.
 const fs = require("node:fs");
 const path = require("node:path");
-const KEYS = ["mvSeparate", "padUsed"];
+const KEYS = ["mvSeparate", "padUsed", "pcView"];
 const valid = value => value === "0" || value === "1";
 
 function preferenceStore(file) {

app/test/preferences.test.js

@@ -36,7 +36,7 @@ test("client choices survive a new native session and local server origin", t =>
   assert.deepEqual(first.read(), { mvSeparate: "1", padUsed: "1" });
 });
 
-test("only the two non-sensitive binary choices can enter the native store", t => {
+test("only the non-sensitive binary choices can enter the native store", t => {
   const file = fixture(t), store = preferenceStore(file);
   for (const [key, value] of [["token", "secret"], ["__proto__", "1"], ["padUsed", true], ["mvSeparate", "yes"]]) {
     assert.throws(() => store.write(key, value), /Invalid preference/);
@@ -58,3 +58,11 @@ test("a missing or damaged preference file retains usable defaults", t => {
   store.write("padUsed", "1");
   assert.deepEqual(store.read(), { padUsed: "1" });
 });
+
+test("the PC in the headset opt-in is remembered and off unless saved", t => {
+  const file = fixture(t), store = preferenceStore(file);
+  assert.equal(store.read().pcView, undefined);
+  store.write("pcView", "1");
+  assert.deepEqual(preferenceStore(file).read(), { pcView: "1" });
+  assert.throws(() => store.write("pcView", "on"), /Invalid preference/);
+});

bench/results/2026-09-28-c5fc552-dirty-pc-agent-frame-arm64-hairpin.json

@@ -0,0 +1,311 @@
+{
+ "label": "pc-agent-frame-arm64-hairpin",
+ "date": "2026-09-28T22:36:19",
+ "commit": "c5fc552+dirty",
+ "config": {
+  "quality": "balanced",
+  "mode": "separate",
+  "net": "none",
+  "delay_ms": 0,
+  "buffer_ms": 250,
+  "host": "frame",
+  "usb": false,
+  "ssh_opts": [],
+  "encoder": "",
+  "duration_s": 10.0,
+  "browser_flags": []
+ },
+ "frame_build": "20260925.6191901",
+ "mac": "26.5.2",
+ "host_platform": "Linux aarch64, SteamOS Frame, BUILD_ID 20260925.6191901 (synthetic host only)",
+ "source": "",
+ "pc_host": true,
+ "headset": "0:03.056203 [Info] - 1 - leaving standby",
+ "scenarios": [
+  {
+   "scenario": "test",
+   "frames_sent": 351,
+   "frames_drawn": 351,
+   "frames_shown": 324,
+   "duration_s": 10.1,
+   "stages_ms": {
+    "capture": {
+     "p50": 0.1,
+     "p95": 0.2,
+     "p99": 0.5,
+     "n": 351
+    },
+    "queue": {
+     "p50": 0.1,
+     "p95": 0.3,
+     "p99": 0.4,
+     "n": 351
+    },
+    "encode": {
+     "p50": 2.0,
+     "p95": 2.9,
+     "p99": 3.5,
+     "n": 351
+    },
+    "socket": {
+     "p50": 0.1,
+     "p95": 0.4,
+     "p99": 0.6,
+     "n": 351
+    },
+    "network": {
+     "p50": 11.6,
+     "p95": 75.7,
+     "p99": 130.1,
+     "n": 351
+    },
+    "decode": {
+     "p50": 0.7,
+     "p95": 2.1,
+     "p99": 4.1,
+     "n": 351
+    },
+    "draw": {
+     "p50": 0.4,
+     "p95": 0.8,
+     "p99": 1.1,
+     "n": 351
+    },
+    "present": {
+     "p50": 0.8,
+     "p95": 18.1,
+     "p99": 24.9,
+     "n": 324
+    },
+    "content": {
+     "p50": 15.1,
+     "p95": 80.3,
+     "p99": 134.2,
+     "n": 351
+    },
+    "content_shown": {
+     "p50": 21.0,
+     "p95": 71.8,
+     "p99": 146.3,
+     "n": 324
+    }
+   },
+   "fps": 34.8,
+   "fps_shown": 32.0,
+   "late_pct": 53.41,
+   "stall_max": 226.8,
+   "stalls_over_100ms": 7,
+   "mbps": 0.26,
+   "keyframes": 6,
+   "size": "1280x720",
+   "captured": 607,
+   "viewer_never_drawn": 0,
+   "input_ms": {
+    "p50": 43.3,
+    "p95": 98.4,
+    "p99": 110.1,
+    "n": 18
+   },
+   "input_shown_ms": {
+    "p50": 54.7,
+    "p95": 98.9,
+    "p99": 114.0,
+    "n": 18
+   },
+   "input_parts_ms": {
+    "uplink": {
+     "p50": 17.1,
+     "p95": 48.3,
+     "p99": 53.1,
+     "n": 18
+    },
+    "mac": {
+     "p50": 12.5,
+     "p95": 32.9,
+     "p99": 35.7,
+     "n": 18
+    },
+    "back": {
+     "p50": 16.8,
+     "p95": 50.0,
+     "p99": 55.9,
+     "n": 18
+    }
+   },
+   "inputs": {
+    "asked": 18,
+    "sent": 18,
+    "seen": 18
+   },
+   "timeline": [
+    {
+     "t": 0,
+     "fps": 38,
+     "mbps": 0.3,
+     "content_p50": 14.8,
+     "content_p95": 25.3,
+     "bitrate": 2764800,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 1,
+     "fps": 33,
+     "mbps": 0.24,
+     "content_p50": 15.6,
+     "content_p95": 103.5,
+     "bitrate": 3845448,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 2,
+     "fps": 39,
+     "mbps": 0.28,
+     "content_p50": 15.6,
+     "content_p95": 29.9,
+     "bitrate": 5283790,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 3,
+     "fps": 25,
+     "mbps": 0.21,
+     "content_p50": 17.8,
+     "content_p95": 175.9,
+     "bitrate": 2764800,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 4,
+     "fps": 34,
+     "mbps": 0.22,
+     "content_p50": 15.4,
+     "content_p95": 69.8,
+     "bitrate": 2764800,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 5,
+     "fps": 38,
+     "mbps": 0.29,
+     "content_p50": 17.7,
+     "content_p95": 68.7,
+     "bitrate": 2764800,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 6,
+     "fps": 38,
+     "mbps": 0.26,
+     "content_p50": 15.0,
+     "content_p95": 18.2,
+     "bitrate": 3091280,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 7,
+     "fps": 30,
+     "mbps": 0.22,
+     "content_p50": 19.2,
+     "content_p95": 111.0,
+     "bitrate": 1725204,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 8,
+     "fps": 35,
+     "mbps": 0.26,
+     "content_p50": 13.4,
+     "content_p95": 102.6,
+     "bitrate": 1725204,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 9,
+     "fps": 38,
+     "mbps": 0.28,
+     "content_p50": 12.3,
+     "content_p95": 20.9,
+     "bitrate": 1725204,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 10,
+     "fps": 3,
+     "mbps": 0.02,
+     "content_p50": 20.9,
+     "content_p95": 24.7,
+     "bitrate": 1725204,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    }
+   ],
+   "adapt": [],
+   "content_p50": 15.1,
+   "content_p95": 80.3,
+   "input_p50": 43.3,
+   "input_p95": 98.4,
+   "grades": {
+    "input_replies": "local",
+    "content_p50": "local",
+    "content_p95": "acceptable",
+    "input_p50": "local",
+    "input_p95": "acceptable",
+    "fps": "bad",
+    "late_pct": "bad",
+    "stall_max": "acceptable"
+   },
+   "controller": {
+    "target": 3442081,
+    "ceiling": 5529600,
+    "tier": 0,
+    "fps": 60,
+    "scale": 1.0,
+    "baseRtt": 13.334,
+    "inFlight": 1,
+    "slack": 71.738,
+    "adapt": true
+   },
+   "events": [
+    {
+     "t": 3.77,
+     "e": "target 2764800 bit/s; tier 0"
+    },
+    {
+     "t": 7.42,
+     "e": "target 1725204 bit/s; tier 0"
+    }
+   ],
+   "source_fps": 60.1,
+   "cpu": {
+    "host": "not sampled"
+   },
+   "viewer": "h264 software; ANGLE (Mesa, zink Vulkan 1.4(Turnip Adreno (TM) 750 (MESA_TURNIP)), OpenGL 4.6); raf 71 Hz",
+   "show_s": 1.88,
+   "panel": "valve.steam.desktopgame.2001932457",
+   "src": "test",
+   "route": "network"
+  }
+ ],
+ "proof": "Synthetic x264 PC agent runs on the Frame itself, forwarded via Mac and back. Not Windows/Linux desktop capture or laser input."
+}

bench/results/2026-09-28-cd20243-pc-agent-frame-arm64-final.json

@@ -0,0 +1,302 @@
+{
+ "label": "pc-agent-frame-arm64-final",
+ "date": "2026-09-28T22:55:27",
+ "commit": "cd20243",
+ "config": {
+  "quality": "balanced",
+  "mode": "native",
+  "net": "none",
+  "delay_ms": 0,
+  "buffer_ms": 250,
+  "host": "frame",
+  "usb": false,
+  "ssh_opts": [],
+  "encoder": "",
+  "duration_s": 10.0,
+  "browser_flags": []
+ },
+ "frame_build": "20260925.6191901",
+ "mac": "26.5.2",
+ "host_platform": "Linux aarch64, SteamOS Frame, BUILD_ID 20260925.6191901 (synthetic host only)",
+ "source": "",
+ "pc_host": true,
+ "headset": "0:03.056203 [Info] - 1 - leaving standby",
+ "scenarios": [
+  {
+   "scenario": "test",
+   "frames_sent": 400,
+   "frames_drawn": 400,
+   "frames_shown": 339,
+   "duration_s": 10.2,
+   "stages_ms": {
+    "capture": {
+     "p50": 0.1,
+     "p95": 0.1,
+     "p99": 0.2,
+     "n": 400
+    },
+    "queue": {
+     "p50": 0.1,
+     "p95": 0.2,
+     "p99": 0.4,
+     "n": 400
+    },
+    "encode": {
+     "p50": 2.0,
+     "p95": 2.7,
+     "p99": 3.1,
+     "n": 400
+    },
+    "socket": {
+     "p50": 0.1,
+     "p95": 0.3,
+     "p99": 0.4,
+     "n": 400
+    },
+    "network": {
+     "p50": 11.8,
+     "p95": 25.2,
+     "p99": 37.8,
+     "n": 400
+    },
+    "decode": {
+     "p50": 0.7,
+     "p95": 1.5,
+     "p99": 2.0,
+     "n": 400
+    },
+    "draw": {
+     "p50": 0.3,
+     "p95": 0.7,
+     "p99": 1.0,
+     "n": 400
+    },
+    "present": {
+     "p50": 0.8,
+     "p95": 19.3,
+     "p99": 26.8,
+     "n": 339
+    },
+    "content": {
+     "p50": 15.1,
+     "p95": 28.6,
+     "p99": 41.3,
+     "n": 400
+    },
+    "content_shown": {
+     "p50": 17.6,
+     "p95": 39.0,
+     "p99": 47.2,
+     "n": 339
+    }
+   },
+   "fps": 39.3,
+   "fps_shown": 33.4,
+   "late_pct": 50.25,
+   "stall_max": 69.3,
+   "stalls_over_100ms": 0,
+   "mbps": 0.35,
+   "keyframes": 6,
+   "size": "1280x720",
+   "captured": 612,
+   "viewer_never_drawn": 0,
+   "input_ms": {
+    "p50": 76.6,
+    "p95": 98.2,
+    "p99": 127.8,
+    "n": 19
+   },
+   "input_shown_ms": {
+    "p50": 80.5,
+    "p95": 107.8,
+    "p99": 128.1,
+    "n": 16
+   },
+   "input_parts_ms": {
+    "uplink": {
+     "p50": 36.5,
+     "p95": 57.6,
+     "p99": 83.2,
+     "n": 19
+    },
+    "mac": {
+     "p50": 14.6,
+     "p95": 31.3,
+     "p99": 31.7,
+     "n": 19
+    },
+    "back": {
+     "p50": 15.1,
+     "p95": 32.8,
+     "p99": 36.2,
+     "n": 19
+    }
+   },
+   "inputs": {
+    "asked": 19,
+    "sent": 19,
+    "seen": 19
+   },
+   "timeline": [
+    {
+     "t": 0,
+     "fps": 40,
+     "mbps": 0.34,
+     "content_p50": 11.7,
+     "content_p95": 27.4,
+     "bitrate": 5529600,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 1,
+     "fps": 39,
+     "mbps": 0.37,
+     "content_p50": 11.9,
+     "content_p95": 28.2,
+     "bitrate": 5529600,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 2,
+     "fps": 41,
+     "mbps": 0.35,
+     "content_p50": 11.4,
+     "content_p95": 16.6,
+     "bitrate": 5529600,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 3,
+     "fps": 39,
+     "mbps": 0.37,
+     "content_p50": 12.7,
+     "content_p95": 28.0,
+     "bitrate": 5529600,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 4,
+     "fps": 38,
+     "mbps": 0.33,
+     "content_p50": 15.3,
+     "content_p95": 30.0,
+     "bitrate": 5529600,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 5,
+     "fps": 39,
+     "mbps": 0.37,
+     "content_p50": 16.7,
+     "content_p95": 28.5,
+     "bitrate": 5529600,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 6,
+     "fps": 41,
+     "mbps": 0.38,
+     "content_p50": 15.9,
+     "content_p95": 29.4,
+     "bitrate": 5529600,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 7,
+     "fps": 41,
+     "mbps": 0.31,
+     "content_p50": 15.6,
+     "content_p95": 28.2,
+     "bitrate": 5529600,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 8,
+     "fps": 38,
+     "mbps": 0.38,
+     "content_p50": 15.5,
+     "content_p95": 25.9,
+     "bitrate": 5529600,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 9,
+     "fps": 38,
+     "mbps": 0.29,
+     "content_p50": 16.7,
+     "content_p95": 28.8,
+     "bitrate": 5529600,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    },
+    {
+     "t": 10,
+     "fps": 6,
+     "mbps": 0.03,
+     "content_p50": 17.6,
+     "content_p95": 23.1,
+     "bitrate": 5529600,
+     "tier": 0,
+     "w": 1280,
+     "net": null
+    }
+   ],
+   "adapt": [],
+   "content_p50": 15.1,
+   "content_p95": 28.6,
+   "input_p50": 76.6,
+   "input_p95": 98.2,
+   "grades": {
+    "input_replies": "local",
+    "content_p50": "local",
+    "content_p95": "local",
+    "input_p50": "acceptable",
+    "input_p95": "acceptable",
+    "fps": "bad",
+    "late_pct": "bad",
+    "stall_max": "local"
+   },
+   "controller": {
+    "target": 5529600,
+    "ceiling": 5529600,
+    "tier": 0,
+    "fps": 60,
+    "scale": 1.0,
+    "baseRtt": 12.332,
+    "inFlight": 0,
+    "slack": 74.12,
+    "adapt": true
+   },
+   "events": [],
+   "source_fps": 60.0,
+   "cpu": {
+    "host": "not sampled"
+   },
+   "viewer": "h264 software; ANGLE (Mesa, zink Vulkan 1.4(Turnip Adreno (TM) 750 (MESA_TURNIP)), OpenGL 4.6); raf 72 Hz",
+   "show_s": 1.75,
+   "panel": "valve.steam.desktopgame.2001932457",
+   "src": "test",
+   "route": "network"
+  }
+ ],
+ "proof": "Synthetic x264 PC agent runs on the Frame itself, forwarded via Mac and back. Not Windows/Linux desktop capture or laser input."
+}

desktop/build-controller.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+"""Build the common controller for the Python PC host (a C11 compiler needed)."""
+import os
+from pathlib import Path
+import subprocess
+import sys
+
+root = Path(__file__).resolve().parent
+suffix = '.dll' if sys.platform == 'win32' else '.dylib' if sys.platform == 'darwin' else '.so'
+out = root / ('controller' + suffix)
+if sys.platform == 'win32' and os.environ.get('CC', 'cl') == 'cl':
+    cmd = ['cl', '/nologo', '/O2', '/LD', '/std:c11', str(root / 'controller.c'), '/link', '/OUT:' + str(out)]
+else:
+    cmd = [os.environ.get('CC', 'cc'), '-O2', '-std=c11', '-shared', '-fPIC', str(root / 'controller.c'), '-o', str(out)]
+subprocess.run(cmd, cwd=root, check=True)
+print(out)

desktop/build.py

@@ -0,0 +1,126 @@
+#!/usr/bin/env python3
+"""Build our native PC adapter and bundle its ordinary shared libraries.
+
+Run on the target architecture after installing GStreamer development packages.
+No GStreamer executable or desktop streaming application is shipped or invoked.
+Linux libc, display/GPU drivers and the portal service remain platform pieces.
+
+x264 is GPL, so the bundle the Windows installer ships leaves it out: Windows
+encodes with Media Foundation. --with-x264 adds it for CI's headless protocol
+tests, which have no GPU or desktop to encode with.
+"""
+import argparse
+import json
+import os
+from pathlib import Path
+import re
+import shutil
+import subprocess
+import sys
+
+ROOT = Path(__file__).resolve().parent
+
+
+def output(*args):
+    return subprocess.check_output(args, text=True).strip()
+
+
+def build(destination, with_x264=False):
+    win = sys.platform == 'win32'
+    destination.mkdir(parents=True, exist_ok=True)
+    modules = ['gstreamer-1.0', 'gstreamer-app-1.0', 'gstreamer-video-1.0']
+    if not win:
+        modules += ['gio-unix-2.0']
+    import shlex
+    flags = shlex.split(output('pkg-config', '--cflags', '--libs', *modules))
+    lib = destination / ('pc-host.dll' if win else 'pc-host.so')
+    cmd = [os.environ.get('CC', 'gcc' if win else 'cc'), '-std=c11', '-O2', '-shared', '-Wall', '-Wextra']
+    if not win:
+        cmd += ['-fPIC', '-Wl,-rpath,$ORIGIN/lib']
+    subprocess.run(cmd + [str(ROOT / f) for f in ('controller.c', 'capture.c', 'portal.c')] + flags + ['-o', str(lib)], check=True)
+    prefix = Path(output('pkg-config', '--variable=prefix', 'gstreamer-1.0'))
+    plugin_dir = Path(output('pkg-config', '--variable=pluginsdir', 'gstreamer-1.0'))
+    plugins_out, libs_out = destination / 'lib' / 'gstreamer-1.0', destination / ('bin' if win else 'lib')
+    plugins_out.mkdir(parents=True, exist_ok=True)
+    libs_out.mkdir(parents=True, exist_ok=True)
+    names = ['coreelements', 'videotestsrc', 'videoconvertscale', 'app', 'jpeg', 'videoparsersbad']
+    if with_x264:
+        names.append('x264')
+    names += ['d3d11', 'mediafoundation'] if win else ['pipewire', 'va']
+    pending = [lib]
+    for name in names:
+        matches = list(plugin_dir.glob('*gst' + name + ('.dll' if win else '.so')))
+        if not matches:
+            raise SystemExit('Missing GStreamer library: ' + name)
+        for source in matches:
+            target = plugins_out / source.name
+            shutil.copy2(source, target)
+            pending.append(source)
+    if not win:
+        # PipeWire dynamically loads support and protocol modules. ldd cannot
+        # discover those; bundle them with a private client-only config instead
+        # of accidentally loading a different distro's client modules/config.
+        libdir = plugin_dir.parent
+        for relative in ('pipewire-0.3/libpipewire-module-protocol-native.so',
+                         'pipewire-0.3/libpipewire-module-client-node.so',
+                         'pipewire-0.3/libpipewire-module-adapter.so',
+                         'spa-0.2/support/libspa-support.so',
+                         'spa-0.2/support/libspa-dbus.so',
+                         'spa-0.2/videoconvert/libspa-videoconvert.so'):
+            source = libdir / relative
+            if not source.is_file():
+                raise SystemExit('Missing PipeWire runtime library: ' + str(source))
+            target = destination / 'lib' / relative
+            target.parent.mkdir(parents=True, exist_ok=True)
+            shutil.copy2(source, target)
+            pending.append(source)
+        config = destination / 'share' / 'pipewire'
+        config.mkdir(parents=True, exist_ok=True)
+        (config / 'client.conf').write_text(
+            'context.spa-libs = { support.* = support/libspa-support video.* = videoconvert/libspa-videoconvert }\n'
+            'context.modules = [\n'
+            '  { name = libpipewire-module-protocol-native }\n'
+            '  { name = libpipewire-module-client-node }\n'
+            '  { name = libpipewire-module-adapter }\n'
+            ']\n')
+    copied = set()
+    while pending:
+        binary = pending.pop()
+        if win:
+            imported = re.findall(r'DLL Name:\s*(\S+)', output('objdump', '-p', str(binary)))
+            dependencies = [prefix / 'bin' / name for name in imported]
+        else:
+            dependencies = [Path(p) for p in re.findall(r'=>\s+(/\S+)', output('ldd', str(binary)))]
+        for dep in dependencies:
+            if not dep.is_file() or dep.name in copied:
+                continue
+            if not win and re.match(r'lib(c|m|dl|rt|pthread|resolv)\.so', dep.name):
+                continue
+            shutil.copy2(dep, libs_out / dep.name)
+            copied.add(dep.name)
+            pending.append(dep)
+    # License texts and package provenance accompany the dynamically linked
+    # libraries. Distribution builders keep the upstream package/source URLs.
+    licenses = destination / 'licenses'
+    licenses.mkdir(exist_ok=True)
+    if win:
+        source = prefix / 'share' / 'licenses'
+        if source.exists():
+            shutil.copytree(source, licenses, dirs_exist_ok=True)
+        packages = output('pacman', '-Q') if shutil.which('pacman') else 'See MSYS2 build log'
+    else:
+        packages = output('dpkg-query', '-W', '-f=${Package} ${Version}\n') if shutil.which('dpkg-query') else ''
+        # Debian copyright files contain licenses and source homepage details.
+        for path in Path('/usr/share/doc').glob('*/copyright'):
+            shutil.copy2(path, licenses / (path.parent.name + '.copyright'))
+    (destination / 'libraries.json').write_text(json.dumps(dict(gstreamer=output('pkg-config', '--modversion', 'gstreamer-1.0'),
+        plugins=names, libraries=sorted(copied), packages=packages), indent=2))
+    print(lib)
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--out', type=Path, default=ROOT / 'bundle')
+    parser.add_argument('--with-x264', action='store_true', help='add the GPL x264 encoder (CI tests only, never shipped)')
+    args = parser.parse_args()
+    build(args.out.resolve(), args.with_x264)

desktop/capture.c

@@ -0,0 +1,125 @@
+/* Frame Control's capture/encode adapter. GStreamer is a bundled library;
+ * capture uses WGC on Windows and the consented PipeWire fd on Linux. */
+#include "controller.h"
+#include <gst/gst.h>
+#include <gst/app/gstappsink.h>
+#include <gst/video/video-event.h>
+#include <string.h>
+
+typedef int (*Gate)(int stage, int64_t pts, int64_t capture, int64_t arrived);
+typedef struct {
+    GstElement *pipeline, *encoder, *sink, *raw_queue;
+    Gate gate;
+    GstSample *sample;
+    GstMapInfo map;
+    int mapped;
+    char error[512];
+} Capture;
+typedef struct { const unsigned char *data; int size, key, width, height; int64_t pts; } Encoded;
+FC_API int64_t fc_now(void) {return g_get_monotonic_time();}
+FC_API void fc_gst_init(void) {gst_init(NULL,NULL);}
+FC_API int fc_has_element(const char *name) {
+    GstElementFactory *f=gst_element_factory_find(name);
+    if(!f)return 0;gst_object_unref(f);return 1;
+}
+static GstPadProbeReturn probe(GstPad *pad,GstPadProbeInfo *info,gpointer data) {
+    Capture *c=data; GstBuffer *b=GST_PAD_PROBE_INFO_BUFFER(info);
+    if(!b)return GST_PAD_PROBE_OK;
+    int64_t now=fc_now(), cap=now;
+    GstClock *clock=gst_element_get_clock(c->pipeline);
+    if(clock && GST_BUFFER_PTS_IS_VALID(b)) {
+        GstClockTime current=gst_clock_get_time(clock),origin=gst_element_get_base_time(c->pipeline);
+        if(current>=origin && current-origin>=GST_BUFFER_PTS(b))
+            cap-= (int64_t)((current-origin-GST_BUFFER_PTS(b))/1000);
+    }
+    if(clock)gst_object_unref(clock);
+    int stage=GPOINTER_TO_INT(g_object_get_data(G_OBJECT(pad),"stage"));
+    if(stage==1) return c->gate(stage,(int64_t)GST_BUFFER_PTS(b),cap,now)>0 ? GST_PAD_PROBE_OK : GST_PAD_PROBE_DROP;
+    int phase=0;
+    for(;;) {
+        /* While congested, prefer a newer raw picture queued upstream. If
+         * nothing changed, retain this last picture until the gate opens;
+         * an idle window must not stay stale after a dropped final update. */
+        guint queued=0;
+        if(phase && c->raw_queue)g_object_get(c->raw_queue,"current-level-buffers",&queued,NULL);
+        if(queued)return GST_PAD_PROBE_DROP;
+        int decision=c->gate(phase,(int64_t)GST_BUFFER_PTS(b),cap,now);
+        if(decision)return decision>0 ? GST_PAD_PROBE_OK : GST_PAD_PROBE_DROP;
+        phase=2;g_usleep(2000);
+    }
+}
+FC_API Capture *fc_capture_open(const char *pipeline,Gate gate,char *error,int capacity) {
+    GError *e=NULL;Capture *c=g_new0(Capture,1);c->gate=gate;
+    c->pipeline=gst_parse_launch(pipeline,&e);
+    if(e || !c->pipeline) {
+        g_strlcpy(error,e?e->message:"No pipeline",capacity);
+        if(e)g_error_free(e);if(c->pipeline)gst_object_unref(c->pipeline);g_free(c);return NULL;
+    }
+    c->encoder=gst_bin_get_by_name(GST_BIN(c->pipeline),"enc");
+    c->sink=gst_bin_get_by_name(GST_BIN(c->pipeline),"out");
+    GstElement *raw=gst_bin_get_by_name(GST_BIN(c->pipeline),"gate");
+    if(!c->encoder || !c->sink || !raw) {
+        g_strlcpy(error,"Pipeline is missing enc, out or gate",capacity);
+        if(raw)gst_object_unref(raw);if(c->encoder)gst_object_unref(c->encoder);
+        if(c->sink)gst_object_unref(c->sink);gst_object_unref(c->pipeline);g_free(c);return NULL;
+    }
+    c->raw_queue=gst_bin_get_by_name(GST_BIN(c->pipeline),"raw_queue");
+    GstPad *p=gst_element_get_static_pad(raw,"src");
+    g_object_set_data(G_OBJECT(p),"stage",GINT_TO_POINTER(0));
+    gst_pad_add_probe(p,GST_PAD_PROBE_TYPE_BUFFER,probe,c,NULL);gst_object_unref(p);gst_object_unref(raw);
+    p=gst_element_get_static_pad(c->encoder,"sink");
+    g_object_set_data(G_OBJECT(p),"stage",GINT_TO_POINTER(1));
+    gst_pad_add_probe(p,GST_PAD_PROBE_TYPE_BUFFER,probe,c,NULL);gst_object_unref(p);
+    gst_element_set_state(c->pipeline,GST_STATE_PLAYING);
+    return c;
+}
+FC_API int fc_capture_pull(Capture *c,Encoded *out) {
+    if(c->mapped) {gst_buffer_unmap(gst_sample_get_buffer(c->sample),&c->map);c->mapped=0;}
+    if(c->sample){gst_sample_unref(c->sample);c->sample=NULL;}
+    GstBus *bus=gst_element_get_bus(c->pipeline);
+    GstMessage *m=gst_bus_pop_filtered(bus,GST_MESSAGE_ERROR);gst_object_unref(bus);
+    if(m) {
+        if(GST_MESSAGE_TYPE(m)==GST_MESSAGE_ERROR) {
+            GError *e=NULL;char *debug=NULL;gst_message_parse_error(m,&e,&debug);
+            g_strlcpy(c->error,e->message,sizeof(c->error));g_error_free(e);g_free(debug);
+        } else g_strlcpy(c->error,"The capture source closed",sizeof(c->error));
+        gst_message_unref(m);return -1;
+    }
+    c->sample=gst_app_sink_try_pull_sample(GST_APP_SINK(c->sink),100*GST_MSECOND);
+    if(!c->sample) {
+        if(gst_app_sink_is_eos(GST_APP_SINK(c->sink))) {
+            g_strlcpy(c->error,"The capture source closed",sizeof(c->error));return -1;
+        }
+        return 0;
+    }
+    GstBuffer *b=gst_sample_get_buffer(c->sample);
+    if(!gst_buffer_map(b,&c->map,GST_MAP_READ))return 0;
+    c->mapped=1;out->data=c->map.data;out->size=(int)c->map.size;
+    out->key=!GST_BUFFER_FLAG_IS_SET(b,GST_BUFFER_FLAG_DELTA_UNIT);out->pts=(int64_t)GST_BUFFER_PTS(b);
+    const GstStructure *s=gst_caps_get_structure(gst_sample_get_caps(c->sample),0);
+    gst_structure_get_int(s,"width",&out->width);gst_structure_get_int(s,"height",&out->height);return 1;
+}
+FC_API const char *fc_capture_error(Capture *c) {return c->error;}
+FC_API void fc_capture_bitrate(Capture *c,int bps) {
+    g_object_set(c->encoder,"bitrate",(guint)MAX(1,bps/1000),NULL);
+}
+FC_API void fc_capture_test(Capture *c,uint32_t input) {
+    GstElement *source=gst_bin_get_by_name(GST_BIN(c->pipeline),"source");
+    if(source) {
+        /* Each benchmark click visibly changes the ball, before injection is
+         * timestamped. This is a response, not merely a protocol input echo. */
+        guint color=0xff000000u | ((input*2654435761u)&0x00ffffffu);
+        g_object_set(source,"foreground-color",color,NULL);gst_object_unref(source);
+    }
+}
+FC_API void fc_capture_key(Capture *c) {
+    GstPad *p=gst_element_get_static_pad(c->encoder,"src");
+    gst_pad_send_event(p,gst_video_event_new_upstream_force_key_unit(GST_CLOCK_TIME_NONE,TRUE,0));gst_object_unref(p);
+}
+FC_API void fc_capture_close(Capture *c) {
+    gst_element_set_state(c->pipeline,GST_STATE_NULL);
+    if(c->mapped)gst_buffer_unmap(gst_sample_get_buffer(c->sample),&c->map);
+    if(c->sample)gst_sample_unref(c->sample);
+    if(c->raw_queue)gst_object_unref(c->raw_queue);
+    gst_object_unref(c->sink);gst_object_unref(c->encoder);gst_object_unref(c->pipeline);g_free(c);
+}

desktop/controller.c

@@ -0,0 +1,130 @@
+/* A C port of the Mac agent's RateController (mac/frame-mac-view/Sources/
+ * Controller.swift) for the Windows host. Same gate, demand protection, bitrate
+ * recovery and tier hysteresis; bounded sample buffers. The Mac agent keeps its
+ * Swift original, so a change to either must be made to both:
+ * tests/test_pc_controller.py checks this one against the Swift trace. */
+#include "controller.h"
+#include <stdlib.h>
+#include <string.h>
+#define CAP 1024
+#define MIN(a,b) ((a)<(b)?(a):(b))
+#define MAX(a,b) ((a)>(b)?(a):(b))
+typedef struct { int64_t t, v; uint32_t seq; } Sample;
+typedef struct { Sample a[CAP]; int n; } Samples;
+struct FCController {
+    int max_fps, enabled, ceiling, target, tier, frame_bytes, held, signal, saw_ack;
+    int64_t decrease, increase, below, above, slack;
+    Samples flight, rtts, acked, sent, captures;
+};
+static const int fps[] = {60,45,30,30,30}, scale[] = {100,100,100,75,50};
+static const double floors[] = {.45,.28,.16,.08,0};
+static void remove_first(Samples *s, int n) {
+    s->n -= n; memmove(s->a, s->a+n, (size_t)s->n*sizeof(Sample));
+}
+static void add(Samples *s, Sample v, int cap) {
+    if (s->n >= cap) remove_first(s, 1);
+    s->a[s->n++] = v;
+}
+static void expire(Samples *s, int64_t oldest) {
+    int n=0; while(n<s->n && s->a[n].t<oldest) n++;
+    remove_first(s,n);
+}
+static int64_t base(FCController *c) {
+    int64_t v=0;
+    for(int i=0;i<c->rtts.n;i++) if(!i || c->rtts.a[i].v<v) v=c->rtts.a[i].v;
+    return v;
+}
+static int compare(const void *a, const void *b) {
+    int64_t x=*(const int64_t*)a, y=*(const int64_t*)b;
+    return (x>y)-(x<y);
+}
+static int64_t quantile(Samples *s,int64_t since,int numerator,int denominator) {
+    int64_t a[CAP]; int n=0;
+    for(int i=0;i<s->n;i++) if(s->a[i].t>since) a[n++]=s->a[i].v;
+    if(!n) return 0;
+    qsort(a,(size_t)n,sizeof(int64_t),compare);
+    return a[n*numerator/denominator];
+}
+static int rate(Samples *s) {
+    int64_t total=0; for(int i=0;i<s->n;i++) total+=s->a[i].v;
+    return (int)MIN(total*16,2147483647);
+}
+FCController *fc_new(int max_fps,int enabled) {
+    FCController *c=calloc(1,sizeof(*c));
+    if(c) {c->max_fps=MAX(1,max_fps);c->enabled=enabled;c->slack=40000;}
+    return c;
+}
+void fc_free(FCController *c) {free(c);}
+void fc_ceiling(FCController *c,int bps) {
+    if(!c->target || c->target>bps) c->target=bps;
+    c->ceiling=bps;
+}
+int fc_gate(FCController *c,int64_t now,int counts) {
+    if(!c->enabled || !c->saw_ack) return 1;
+    expire(&c->flight,now-2000000);
+    if(!c->flight.n) return 1;
+    int64_t interval=1000000/MIN(c->max_fps,fps[c->tier]);
+    int window=MAX(3,(int)((base(c)+c->slack)/interval)+1);
+    if(c->flight.n<window && now-c->flight.a[0].t<=base(c)+c->slack) return 1;
+    if(counts) c->held++;
+    return 0;
+}
+void fc_capture(FCController *c,int64_t now) {add(&c->captures,(Sample){now,0,0},256);}
+void fc_sent(FCController *c,uint32_t seq,int bytes,int64_t now) {
+    Sample s={now,bytes,seq};add(&c->flight,s,512);add(&c->sent,s,CAP);
+}
+int fc_ack(FCController *c,uint32_t seq,int64_t now) {
+    c->saw_ack=1;
+    for(int i=0;i<c->flight.n;i++) if(c->flight.a[i].seq==seq) {
+        Sample s=c->flight.a[i];remove_first(&c->flight,i+1);
+        add(&c->rtts,(Sample){now,now-s.t,0},CAP);
+        add(&c->acked,(Sample){now,s.v,0},CAP);return 1;
+    }
+    return 0;
+}
+int fc_update(FCController *c,int64_t now) {
+    expire(&c->rtts,now-10000000);expire(&c->acked,now-500000);
+    expire(&c->sent,now-500000);expire(&c->flight,now-2000000);
+    expire(&c->captures,now-1000000);
+    if(!c->enabled || c->ceiling<=0) return 0;
+    int64_t baseline=base(c), spread=quantile(&c->rtts,now-2000000,9,10);
+    int64_t jitter=spread ? spread-baseline : 0;
+    c->slack=1000000/MIN(c->max_fps,fps[c->tier])+MIN(MAX(jitter*3/2,25000),80000);
+    int64_t recent=quantile(&c->rtts,now-300000,1,2);
+    int64_t queue=recent ? recent-baseline : 0;
+    int64_t age=c->flight.n ? now-c->flight.a[0].t : 0;
+    int delivered=rate(&c->acked),sending=rate(&c->sent);
+    if(c->sent.n) c->frame_bytes=sending/16/c->sent.n;
+    int demand=(int)MIN((int64_t)MIN(c->captures.n,MIN(c->max_fps,fps[c->tier]))*c->frame_bytes*8,2147483647);
+    int signal=(sending>=c->target/2 && queue>40000)||c->held>=3||age>baseline+100000;
+    int congested=signal && c->signal;c->signal=signal;c->held=0;
+    if(congested && now-c->decrease>300000) {
+        int next=MAX(300000,MIN((int64_t)c->target*4/5,MAX((int64_t)delivered*9/10,c->target/2)));
+        if(demand>0 && (int64_t)demand*2<=(int64_t)c->target*5/4) next=MAX(next,MIN(c->target,(int64_t)demand*2));
+        c->target=next;c->decrease=now;
+    } else if(!congested && now-c->decrease>1000000 && now-c->increase>250000 && c->target<c->ceiling &&
+              (sending>(int64_t)c->target*6/10 || now-c->decrease>3000000)) {
+        c->target=MIN(c->ceiling,(int64_t)(c->target*1.1)+50000);c->increase=now;
+    }
+    double share=(double)c->target/MAX(c->ceiling,1);
+    if(c->tier<4 && share<floors[c->tier] && sending>=(int64_t)c->target*7/10) {
+        if(!c->below)c->below=now;
+        if(now-c->below>500000) {
+            for(c->tier=0;c->tier<4 && share<floors[c->tier];c->tier++) {}
+            c->below=0;
+        }
+    } else c->below=0;
+    if(c->tier>0 && share>floors[c->tier-1]*1.25) {
+        if(!c->above)c->above=now;
+        if(now-c->above>2000000) {c->tier--;c->above=0;}
+    } else c->above=0;
+    return c->target;
+}
+int64_t fc_value(FCController *c,int field) {
+    switch(field) {
+    case 0:return c->target;case 1:return c->ceiling;case 2:return c->tier;
+    case 3:return MIN(c->max_fps,fps[c->tier]);case 4:return scale[c->tier];
+    case 5:return base(c);case 6:return c->flight.n;case 7:return c->slack;
+    default:return 0;
+    }
+}

desktop/controller.h

@@ -0,0 +1,29 @@
+/* Shared latency controller. Times are monotonic host microseconds.
+ * Callers serialize access. Capture is gated BEFORE encoding: dropping an
+ * encoded inter frame would break the decoder's reference chain. */
+#ifndef FRAME_CONTROLLER_H
+#define FRAME_CONTROLLER_H
+#include <stdint.h>
+#ifdef _WIN32
+#define FC_API __declspec(dllexport)
+#else
+#define FC_API
+#endif
+#ifdef __cplusplus
+extern "C" {
+#endif
+typedef struct FCController FCController;
+FC_API FCController *fc_new(int fps, int enabled);
+FC_API void fc_free(FCController *c);
+FC_API void fc_ceiling(FCController *c, int bps);
+FC_API int fc_gate(FCController *c, int64_t now, int counts);
+FC_API void fc_capture(FCController *c, int64_t now);
+FC_API void fc_sent(FCController *c, uint32_t seq, int bytes, int64_t now);
+FC_API int fc_ack(FCController *c, uint32_t seq, int64_t now);
+FC_API int fc_update(FCController *c, int64_t now);
+/* target, ceiling, tier, fps, scale percent, baseline us, in flight, slack us */
+FC_API int64_t fc_value(FCController *c, int field);
+#ifdef __cplusplus
+}
+#endif
+#endif

desktop/portal.c

@@ -0,0 +1,147 @@
+/* xdg-desktop-portal RemoteDesktop + ScreenCast, one consented session per
+ * panel. PipeWire receives the portal fd, never the unrestricted daemon fd.
+ * Input uses only the devices granted in Start's response. */
+#ifndef _WIN32
+#include "controller.h"
+#include <gio/gio.h>
+#include <gio/gunixfdlist.h>
+#include <unistd.h>
+#include <string.h>
+#define BUS "org.freedesktop.portal.Desktop"
+#define PATH "/org/freedesktop/portal/desktop"
+#define RD "org.freedesktop.portal.RemoteDesktop"
+#define SC "org.freedesktop.portal.ScreenCast"
+typedef struct {
+    GDBusConnection *bus;
+    GMainContext *context;
+    char *session;
+    int fd;
+    unsigned node, devices;
+    int width,height;
+} Portal;
+typedef struct {GVariant *result;int done;unsigned code;} Response;
+static void response(GDBusConnection *c,const char *sender,const char *path,const char *iface,
+                     const char *signal,GVariant *params,gpointer data) {
+    (void)c;(void)sender;(void)path;(void)iface;(void)signal;
+    Response *r=data;g_variant_get(params,"(u@a{sv})",&r->code,&r->result);r->done=1;
+}
+static void option(GVariantBuilder *b,const char *key,GVariant *v) {g_variant_builder_add(b,"{sv}",key,v);}
+static GVariant *request(Portal *p,const char *iface,const char *method,GVariant *args,
+                         const char *token,char *error,int capacity) {
+    char *sender=g_strdup(g_dbus_connection_get_unique_name(p->bus)+1);
+    for(char *c=sender;*c;c++)if(*c=='.')*c='_';
+    char *path=g_strdup_printf(PATH "/request/%s/%s",sender,token);g_free(sender);
+    Response r={0};GError *e=NULL;
+    guint sub=g_dbus_connection_signal_subscribe(p->bus,BUS,"org.freedesktop.portal.Request","Response",
+                                                 path,NULL,G_DBUS_SIGNAL_FLAGS_NONE,response,&r,NULL);
+    GVariant *reply=g_dbus_connection_call_sync(p->bus,BUS,PATH,iface,method,args,G_VARIANT_TYPE("(o)"),
+                                               G_DBUS_CALL_FLAGS_NONE,10000,NULL,&e);
+    if(reply)g_variant_unref(reply);
+    int64_t deadline=g_get_monotonic_time()+120000000;
+    while(!e && !r.done && g_get_monotonic_time()<deadline) {
+        while(g_main_context_iteration(p->context,FALSE)) {}
+        g_usleep(10000);
+    }
+    if(!r.done) {
+        GVariant *closed=g_dbus_connection_call_sync(p->bus,BUS,path,"org.freedesktop.portal.Request","Close",
+                                NULL,NULL,G_DBUS_CALL_FLAGS_NONE,2000,NULL,NULL);
+        if(closed)g_variant_unref(closed);
+    }
+    g_dbus_connection_signal_unsubscribe(p->bus,sub);g_free(path);
+    if(e || !r.done || r.code) {
+        g_strlcpy(error,e?e->message:!r.done?"Screen sharing request timed out":"Screen sharing was cancelled or refused",capacity);
+        if(e)g_error_free(e);if(r.result)g_variant_unref(r.result);return NULL;
+    }
+    return r.result;
+}
+FC_API void fc_portal_close(Portal *p) {
+    if(!p)return;
+    if(p->session && p->bus) {
+        GVariant *r=g_dbus_connection_call_sync(p->bus,BUS,p->session,"org.freedesktop.portal.Session","Close",
+                                                NULL,NULL,G_DBUS_CALL_FLAGS_NONE,2000,NULL,NULL);
+        if(r)g_variant_unref(r);
+    }
+    if(p->fd>=0){close(p->fd);p->fd=-1;}
+    g_free(p->session);if(p->bus)g_object_unref(p->bus);
+    if(p->context)g_main_context_unref(p->context);g_free(p);
+}
+/* Each pipeline gets a fresh restricted PipeWire connection. A dup of a
+ * previously consumed protocol socket is not a new connection.
+ * Ownership: the Portal owns p->fd for its whole life and is its only closer.
+ * pipewiresrc never takes the fd it is given: its core connects with
+ * pw_context_connect_fd(ctx, fcntl(fd, F_DUPFD_CLOEXEC, 3), ...) and that
+ * duplicate is what PipeWire closes on teardown (src/gst/gstpipewirecore.c,
+ * unchanged from 0.3.19 through 1.x). So closing p->fd here is not a double
+ * close; not closing it would leak one socket per pipeline reopen. The
+ * caller closes the previous pipeline before asking for a new fd. */
+FC_API int fc_portal_refresh(Portal *p,char *error,int capacity) {
+    GVariantBuilder b;g_variant_builder_init(&b,G_VARIANT_TYPE_VARDICT);
+    GUnixFDList *fds=NULL;GError *e=NULL;
+    GVariant *r=g_dbus_connection_call_with_unix_fd_list_sync(p->bus,BUS,PATH,SC,"OpenPipeWireRemote",
+         g_variant_new("(oa{sv})",p->session,&b),G_VARIANT_TYPE("(h)"),G_DBUS_CALL_FLAGS_NONE,10000,NULL,&fds,NULL,&e);
+    if(!r){g_strlcpy(error,e->message,capacity);g_error_free(e);return -1;}
+    int handle;g_variant_get(r,"(h)",&handle);g_variant_unref(r);
+    int fd=g_unix_fd_list_get(fds,handle,&e);g_object_unref(fds);
+    if(fd<0){g_strlcpy(error,e->message,capacity);g_error_free(e);return -1;}
+    if(p->fd>=0)close(p->fd);
+    p->fd=fd;return fd;
+}
+FC_API Portal *fc_portal_select(char *error,int capacity) {
+    Portal *p=g_new0(Portal,1);p->fd=-1;p->context=g_main_context_new();
+    g_main_context_push_thread_default(p->context);
+    GError *e=NULL;GVariant *r=NULL;
+    p->bus=g_bus_get_sync(G_BUS_TYPE_SESSION,NULL,&e);
+    if(!p->bus) {g_strlcpy(error,e->message,capacity);g_error_free(e);goto fail;}
+    GVariantBuilder b;char token[64],session[64];
+    g_snprintf(session,sizeof(session),"fc_%u",g_random_int());
+    g_snprintf(token,sizeof(token),"fc_%u",g_random_int());
+    g_variant_builder_init(&b,G_VARIANT_TYPE_VARDICT);
+    option(&b,"handle_token",g_variant_new_string(token));option(&b,"session_handle_token",g_variant_new_string(session));
+    r=request(p,RD,"CreateSession",g_variant_new("(a{sv})",&b),token,error,capacity);if(!r)goto fail;
+    g_variant_lookup(r,"session_handle","s",&p->session);g_variant_unref(r);r=NULL;
+    if(!p->session){g_strlcpy(error,"Portal did not return a session",capacity);goto fail;}
+    g_snprintf(token,sizeof(token),"fc_%u",g_random_int());g_variant_builder_init(&b,G_VARIANT_TYPE_VARDICT);
+    option(&b,"handle_token",g_variant_new_string(token));option(&b,"types",g_variant_new_uint32(3));
+    r=request(p,RD,"SelectDevices",g_variant_new("(oa{sv})",p->session,&b),token,error,capacity);if(!r)goto fail;g_variant_unref(r);
+    g_snprintf(token,sizeof(token),"fc_%u",g_random_int());g_variant_builder_init(&b,G_VARIANT_TYPE_VARDICT);
+    option(&b,"handle_token",g_variant_new_string(token));option(&b,"types",g_variant_new_uint32(3));
+    option(&b,"multiple",g_variant_new_boolean(FALSE));option(&b,"cursor_mode",g_variant_new_uint32(2));
+    r=request(p,SC,"SelectSources",g_variant_new("(oa{sv})",p->session,&b),token,error,capacity);if(!r)goto fail;g_variant_unref(r);
+    g_snprintf(token,sizeof(token),"fc_%u",g_random_int());g_variant_builder_init(&b,G_VARIANT_TYPE_VARDICT);
+    option(&b,"handle_token",g_variant_new_string(token));
+    r=request(p,RD,"Start",g_variant_new("(osa{sv})",p->session,"",&b),token,error,capacity);if(!r)goto fail;
+    g_variant_lookup(r,"devices","u",&p->devices);
+    GVariant *streams=g_variant_lookup_value(r,"streams",G_VARIANT_TYPE("a(ua{sv})"));
+    if(streams && g_variant_n_children(streams)>0) {
+        GVariant *entry=g_variant_get_child_value(streams,0),*props=NULL;
+        g_variant_get(entry,"(u@a{sv})",&p->node,&props);
+        g_variant_lookup(props,"size","(ii)",&p->width,&p->height);
+        g_variant_unref(props);g_variant_unref(entry);
+    }
+    if(streams)g_variant_unref(streams);g_variant_unref(r);r=NULL;
+    if(!p->node || p->width<=0 || p->height<=0) {g_strlcpy(error,"Portal returned no stream size",capacity);goto fail;}
+    if(fc_portal_refresh(p,error,capacity)<0)goto fail;
+    g_main_context_pop_thread_default(p->context);return p;
+fail:
+    g_main_context_pop_thread_default(p->context);fc_portal_close(p);return NULL;
+}
+FC_API int fc_portal_value(Portal *p,int field) {
+    switch(field){case 0:return p->fd;case 1:return (int)p->node;case 2:return p->width;
+                 case 3:return p->height;case 4:return (int)p->devices;default:return 0;}
+}
+FC_API int fc_portal_input(Portal *p,int type,double x,double y,int code,int down) {
+    const char *method=NULL;GVariant *args=NULL;GVariantBuilder b;g_variant_builder_init(&b,G_VARIANT_TYPE_VARDICT);
+    if(type==0 && (p->devices&2)) {
+        method="NotifyPointerMotionAbsolute";args=g_variant_new("(oa{sv}udd)",p->session,&b,p->node,x,y);
+    } else if(type==1 && (p->devices&2)) {
+        method="NotifyPointerButton";args=g_variant_new("(oa{sv}iu)",p->session,&b,code,(guint)down);
+    } else if(type==2 && (p->devices&2)) {
+        method="NotifyPointerAxis";args=g_variant_new("(oa{sv}dd)",p->session,&b,x,y);
+    } else if(type==3 && (p->devices&1)) {
+        method="NotifyKeyboardKeysym";args=g_variant_new("(oa{sv}iu)",p->session,&b,code,(guint)down);
+    } else return 0;
+    GError *e=NULL;GVariant *r=g_dbus_connection_call_sync(p->bus,BUS,PATH,RD,method,args,NULL,
+                                                       G_DBUS_CALL_FLAGS_NONE,2000,NULL,&e);
+    if(e)g_error_free(e);if(r)g_variant_unref(r);return r!=NULL;
+}
+#endif

docs/backup-and-recovery.md

@@ -0,0 +1,167 @@
+# Backup and recovery
+
+**Tools → Backup & recovery** copies what a factory reset would lose from the
+Steam Frame to your computer, puts it back afterwards, and gets the headset out
+of Desktop Mode. It runs from Frame Control on a computer, not from the iPhone
+app or the Frame itself.
+
+**Partly tested on a headset.** On a Frame running SteamOS 0.5.6 (build
+20261015.6141207), a full backup saved 26 parts (40.7 MB): 14 games' Proton
+saves, Linux game saves, Steam and desktop settings and 9 Android apps' data,
+with no sign-in files or keys in the archives. Restoring one game's saves on top
+of identical files wrote nothing and left nothing behind. The session check
+reported Game Mode, so **Return to Game Mode** changed nothing. Not tested on a
+headset: a restore after a real factory reset, a restore that replaces files,
+Android data restore, and the switch out of a real Desktop Mode session. Unit
+tests and the fake Frame cover those (see [Verification](#verification)).
+
+## Back up
+
+Choose **Game saves**, **Steam and desktop settings** and **Android app data**
+(all three by default), then **Back up now**. **See what's included** lists each
+part and its size first. Backing up only reads the headset.
+
+Each backup is a folder named after the time it started:
+
+```
+~/Documents/Frame Control Backups/2026-10-23-142530/
+  manifest.json
+  saves/saves-1234.tar.gz          one per game
+  saves/saves-linux.tar.gz
+  settings/settings-steam.tar.gz
+  settings/settings-system.tar.gz
+  android/org.example.game.tar.gz  one per Android app
+```
+
+`manifest.json` records the headset's name, SteamOS version and BUILD_ID, every
+file with its size and SHA-256, and each archive's SHA-256. It also lists what
+was skipped and why. A backup is written under a hidden `.…partial` name and
+renamed when complete, so a cut-off backup never shows up as one.
+
+### What's saved
+
+| Part | From the headset (`~` is `/home/steamos`) | Restored? |
+|---|---|---|
+| Windows game saves | `~/.local/share/Steam/steamapps/compatdata/<appid>/pfx/drive_c/users/steamuser/` → `AppData/Roaming`, `AppData/Local`, `AppData/LocalLow`, `Documents`, `Saved Games`. Wine's own folders in them (`Temp`, `Microsoft`, `D3DSCache`, `CrashDumps`) are left out. Sideloaded Windows games (non-Steam shortcuts) have prefixes here too | Yes |
+| Linux game saves | `~/.config/unity3d`, `~/.local/share/godot/app_userdata`: where Unity and Godot games save by default | Yes |
+| Steam controller layouts | `userdata/<account>/241100/remote/controller_config`, `steamapps/common/Steam Controller Configs/<account>/config` | Yes |
+| Steam library settings | `userdata/<account>/config/localconfig.vdf`, `shortcuts.vdf`, `grid/` (custom artwork) | Kept for reference |
+| Desktop settings | `~/.config/kdeglobals`, `kwinrc`, `kxkbrc` (keyboard layout), `konsolerc`, `dolphinrc` | Yes |
+| SteamVR settings | `~/.config/openvr/config/steamvr.vrsettings` | Kept for reference |
+| Android app data | Each Frame Control Android app's private data, through the existing `backup-data` helper ([sidequest.md](sidequest.md#private-app-data-backups)) | Yes |
+
+"Kept for reference" files are in the backup but not put back automatically:
+Steam and SteamVR rewrite them while they run, and an old `shortcuts.vdf` would
+point at apps that aren't installed after a reset. Open the backup folder to
+copy one by hand if you need it.
+
+### What's never copied
+
+- **Steam sign-in:** `steam.token`, `config/config.vdf`, `loginusers.vdf`,
+  `registry.vdf` and `ssfn*` files.
+- **Keys and passwords:** `~/.ssh`, `~/.gnupg`, keyrings and KWallet, any
+  `*.token`, `*.key` or `*.pem` file, Tailscale state and proxy settings
+  (`secrets.env`). These are refused by name wherever they turn up, including
+  inside a game's folder, and a restore refuses them too.
+- Games, Proton and the Steam runtimes: reinstall them from Steam.
+- Steam Cloud's own folders (`userdata/<account>/<appid>`), shader caches and
+  screenshots (**Tools → Capture & Live** saves those to Pictures).
+- Android apps themselves, their OBB files and shared storage (`/sdcard`).
+- Symbolic links (never followed), and single files over 2 GiB.
+
+Backups aren't encrypted. Game folders can still hold a launcher's login, and
+Android app data can hold an app's, so keep backups private.
+
+Android apps that are open are skipped (the helper needs the app closed); close
+them and back up again.
+
+## Restore after a factory reset
+
+1. Set up the headset again: Developer Mode, **Set Up Connection**, sign in to
+   Steam with the same account.
+2. Reinstall your games, and **start each once** so Proton creates its folders.
+3. Reinstall your Android apps from Frame Control.
+4. **Tools → Backup & recovery → Restore…** on a backup. Frame Control checks
+   each part against the headset and says what it would do: how many files it
+   replaces and how many are new.
+5. Tick the parts to restore and **Restore selected**. It asks before replacing
+   anything.
+
+Parts that can't go back yet are skipped, not failed, with the reason:
+
+| Reason | What to do |
+|---|---|
+| Install the game first | Install it from Steam, then restore |
+| Start the game once | Proton hasn't made its folders yet; start the game, quit, restore |
+| Sign in to Steam first | Controller layouts go under your account's folder |
+| Install the app first / close the app first | Android app data needs the app installed and closed |
+| The backup file doesn't match its checksum | The archive changed since it was made |
+
+A restore writes only the files in the parts you chose, and only inside that
+part's folders: it never deletes a file, and a save archive can't write outside
+its game. Before replacing a file it copies the current one to
+`~/.local/share/frame-control/restore-previous/<time>/` on the headset. Files
+already identical are left alone. Android app data goes through the existing
+`restore-data` helper, which keeps the previous data folder beside it.
+
+## Stuck in Desktop Mode
+
+On the Frame, Game Mode is gamescope running Steam, and the Linux desktop
+normally runs *inside* it as one panel (`steamos-nested-desktop`, see
+[how-the-frame-works.md](how-the-frame-works.md#the-layer-cake)). If that panel
+is what you see, you're already in Game Mode: close it from the Steam dashboard.
+
+Full Desktop Mode is a different session. SteamOS picks the session through
+SDDM's autologin file, `/etc/sddm.conf.d/zz-steamos-autologin.conf` (or the
+default `/etc/sddm.conf.d/steamos.conf`), and switches with
+`steamos-session-select` (`holo-session-select` on newer images). This is what
+Valve's own devkit tools on the Frame read and run
+([`steamos-get-status`](../frame/devkit-utils/steamos-get-status),
+[`steamos-delete`](../frame/devkit-utils/steamos-delete)).
+
+**Check** reads that file and whether gamescope and Plasma are running; it
+changes nothing. On the Frame gamescope's process is `gamescope-wl`, started by
+`start-gamescope-session`, and either counts as Game Mode. Only when Plasma is
+running without gamescope (Desktop Mode) does **Return to Game Mode** run
+exactly `steamos-session-select gamescope` (or `holo-session-select
+gamescope`) over SSH, after asking. It closes the desktop and anything open in
+it. Frame Control never edits the SDDM files itself, and runs nothing when the
+headset is in Game Mode, when it can't tell which mode it's in, or when the
+image has neither command.
+
+**Uncertain:** whether the Frame offers a full Desktop Mode session at all
+(only the nested desktop has been seen on BUILD_ID 20260922.6101926 and
+20260925.6191901), and whether `steamos-session-select` there works without
+the Developer Mode password. If the switch is refused, Frame Control says so and
+leaves the headset as it was.
+
+### Manual fallback
+
+If the button can't help, or the headset isn't reachable:
+
+1. **Restart it:** hold Power about 10 seconds until the light goes off, then
+   power on. On the Steam Deck, **Switch to Desktop** starts a one-shot
+   Desktop Mode session, so a restart brings Game Mode back. That the Frame
+   behaves the same is **inferred**, not tested.
+2. **Over SSH** (Developer Mode on), run Valve's switch yourself:
+   `ssh frame steamos-session-select gamescope`.
+3. **Boot menu:** hold Power 10 seconds, then power on while holding the AUX
+   button on top of Power. Choose `Current`, or `Previous` to start the other
+   SteamOS slot; both keep your data. Details and the further options
+   (`Repair Steam Installation`, `Erase User Data`, a full re-image) are in
+   [how-the-frame-works.md](how-the-frame-works.md#facts-worth-knowing) and
+   [recovery-and-images.md](recovery-and-images.md). Back up first if you can:
+   `Erase User Data` is a factory reset.
+
+## Verification
+
+`tests/test_backup.py` runs the headset-side script (`ui/frame_backup_remote.py`)
+for real against a folder laid out like the Frame's home, with only SSH faked:
+which paths are picked, that sign-in files and keys never are (also inside game
+folders), links never followed, the manifest and its checksums, restore checks
+after a reset (game not installed, no Proton folders yet, not signed in), that a
+restore replaces only its own files and keeps the old ones, unsafe archives
+(`..`, absolute paths, links, other games' folders) writing nothing, backup
+names that try to leave the backups folder, and the exact Game Mode command.
+`tests/e2e/test_recovery_kit.py` backs up a Proton save from the fake Frame through
+the server, deletes it and restores it. Neither involves a real headset.

docs/frame-control.md

@@ -53,6 +53,11 @@ counts them while they run.
   `~/Videos/SteamFrame`, and **Steam clips**: export clips and background
   recordings from Steam's game recording at any length, without re-encoding.
   See [recording.md](recording.md). Not tested on a headset yet.
+- **Backup & recovery** (Tools): copy game saves, settings and Android app data
+  to `~/Documents/Frame Control Backups/<time>/` with a checksummed manifest,
+  restore chosen parts after a factory reset, and **Return to Game Mode** when
+  the headset is stuck in Desktop Mode. Sign-in files and keys are never copied.
+  Not tested on a headset yet. See [backup-and-recovery.md](backup-and-recovery.md).
 - **Battery** with charging state: charge rate in watts, time to full or empty,
   charger type and wattage (for example USB-C PD 20 W), and battery temperature.
 - **Status**: storage, memory, temperature, Wi-Fi, uptime, and whether SteamVR,

docs/how-the-frame-works.md

@@ -96,5 +96,6 @@ ssh frame 'cat /opt/steamvr/resources/webinterface/dashboard/localization/dashbo
 - Remote access from anywhere: [tailscale.md](tailscale.md)
 - Floating windows in space: [panels.md](panels.md)
 - Recovery images, what's in them, testing without the headset: [recovery-and-images.md](recovery-and-images.md)
+- Backing up saves and settings, restoring after a reset, leaving Desktop Mode: [backup-and-recovery.md](backup-and-recovery.md)
 - Frame Control on iPhone (the server running on the Frame itself): [iphone.md](iphone.md)
 - What's still unverified: [open-questions.md](open-questions.md)

docs/mac-in-headset.md

@@ -4,7 +4,8 @@ Frame Control can show any Mac window, or a whole Mac screen, as its own panel
 in the Steam Frame. You place each panel anywhere in the room with the SteamVR
 dashboard. The laser clicks and drags, the thumbstick scrolls, and you type on
 the Mac's own keyboard. Find it under **Tools → Mac in the headset** (macOS
-only).
+only). On Windows there's an experimental port,
+[PC in the headset](pc-in-headset.md).
 
 The confidence labels are the same as in [ssh.md](ssh.md).
 

docs/pc-in-headset.md

@@ -0,0 +1,137 @@
+# PC in the headset (Experimental)
+
+**Tools → PC in the headset**, on Windows only. It's the Windows version of
+[Mac in the headset](mac-in-headset.md): a window or a whole screen on your PC
+becomes its own SteamVR panel in the Frame. Place it with the dashboard's Float
+in World, Move and Size, point and click with the laser, scroll with the
+thumbstick, and type on the PC's keyboard.
+
+**It's experimental and not yet tried on a real Windows desktop or with a
+headset.** It builds and passes its protocol tests on Windows in CI, but desktop
+capture, Media Foundation encoding and laser input have never run on a real
+PC. Expect it not to work yet. Reports are welcome through the
+[feedback form](https://frame-control.pages.dev/feedback/).
+
+## Turning it on
+
+It's off by default. Until you tick **Turn on PC in the headset** on the card,
+Frame Control starts no helper, loads none of the streaming libraries and lists
+no windows. The choice is remembered on this computer. Turning it off ends
+every stream, closes the viewers in the headset and stops the helper.
+
+The card and its Tools link only appear in the Windows app. On macOS the card
+is Mac in the headset, as before; on Linux and the iPhone app there's no card.
+
+## How it works
+
+The ported pieces are from [PR #38](https://github.com/saphid/frame-control/pull/38).
+Frame Control owns the host helper, input, authentication, streaming protocol,
+panel launcher and adaptation. It doesn't need Sunshine, OBS or any other
+streaming app. GStreamer is bundled as ordinary libraries.
+
+| | Windows |
+|---|---|
+| Capture | Windows.Graphics.Capture, through GStreamer's `d3d11screencapturesrc capture-api=wgc`, by window (HWND) or screen (HMONITOR) |
+| Encoding | Media Foundation's H.264 encoder (`mfh264enc`), low latency, no B-frames. Whether it uses the GPU depends on the PC; **not verified** |
+| Input | `SendInput`, mapped through the source's bounds, with per-monitor DPI awareness |
+
+API choices are documented, not device-verified:
+[Windows capture](https://learn.microsoft.com/en-us/windows/uwp/audio-video-camera/screen-capture),
+[GStreamer WGC](https://gstreamer.freedesktop.org/documentation/d3d11/d3d11screencapturesrc.html),
+[Media Foundation encoder](https://gstreamer.freedesktop.org/documentation/mediafoundation/mfh264enc.html).
+
+It needs Windows 10 or 11 with Windows.Graphics.Capture and a Media Foundation
+H.264 encoder (Windows "N" editions need the Media Feature Pack). Clicks and
+keys can't reach administrator apps or the sign-in screen, which an ordinary
+process can't drive. If Windows won't bring the chosen window to the front,
+input is refused rather than sent to the app covering it: bring the window
+forward, then Stop and Show again. Minimised or closed windows stop sending
+pictures. Protected video isn't supported. Mac in the headset's "own display
+per window" is Mac-only.
+
+The pieces it shares with Mac in the headset:
+
+- `ui/frame_macview.py` owns the SSH tunnel, reconnects, quality presets and
+  panel launch. `ui/frame_pcview.py` picks the Windows helper
+  (`ui/frame_pc_agent.py`, `ui/frame_pc_capture.py`, `desktop/capture.c`) and
+  holds the on/off switch. `/api/macview` is the endpoint for both.
+- `ui/mac-view.html` is the one viewer in the headset. Its frame header, H.264
+  and JPEG payloads, reconnect handshake, clock sync, timing reports and input
+  messages are unchanged.
+- `desktop/controller.c` is a C port of the Mac helper's Swift rate controller,
+  for the Windows helper. The Mac keeps its Swift original;
+  `tests/test_pc_controller.py` checks the port against a frozen 600-state
+  trace from it. Capture is gated before encoding, so encoded frames are never
+  dropped, and an idle window's last picture still goes out once the link
+  clears.
+- Stream records use the Mac helper's JSON schema (`ui/frame_stream_stats.py`),
+  so the benchmark's analysis is shared.
+
+## Packaging
+
+The Windows installer carries `resources/desktop/bundle`: `pc-host.dll` (our
+adapter and the controller), the GStreamer plugins it uses (`coreelements`,
+`videotestsrc`, `videoconvertscale`, `app`, `jpeg`, `videoparsersbad`,
+`d3d11`, `mediafoundation`) and the DLLs they depend on, all from MSYS2's
+UCRT64 packages. `libraries.json` records the GStreamer version, the plugins,
+each copied DLL and the exact package versions; licence texts are in
+`licenses/`.
+
+The x264 encoder is **not** in the installer. It's GPL, and Windows encodes
+with Media Foundation, so only CI's test builds include it
+(`desktop/build.py --with-x264`). The macOS and Linux installers are unchanged.
+
+From a source checkout on Windows, build the bundle from an MSYS2 UCRT64 shell
+with the packages listed in `.github/workflows/pc-host.yml`:
+
+```sh
+python desktop/build.py              # what the installer ships
+python desktop/build.py --with-x264  # for the native tests
+```
+
+A missing bundle is reported on the card; nothing is downloaded on first use.
+
+The Linux adapter from #38 (desktop portal, PipeWire, VA-API) is in the tree,
+because it shares `capture.c` and the controller, and CI still builds and tests
+it. The app never offers it and the Linux installers don't include it.
+
+## Measuring
+
+The Mac benchmark accepts the PC host:
+
+```sh
+python scripts/macview-bench.py run --pc --scenario test --label pc-test
+python scripts/macview-bench.py run --pc --scenario capture --source window:12345 --label windows-window
+```
+
+`capture` needs a window or screen id from the helper's `/windows` or
+`/displays`. CPU sampling isn't available on PC hosts. See
+[Mac in the headset](mac-in-headset.md) for the targets and shaping options.
+
+## What's verified
+
+- **Verified in CI, this PR:** on `windows-latest`, the native adapter builds
+  and a real x264 synthetic stream passes the ticket, reconnect, timing and
+  input-echo tests through the helper. The Windows installer builds with the
+  bundle, and its bundled Python loads the bundle, starts the helper and
+  confirms x264 isn't in it. Unit tests check the Windows-only, off-by-default
+  gating, the card and the Tools link on macOS, Windows and Linux.
+- **Verified, #38, 2026-09-28, real Frame on SteamOS BUILD_ID 20260925.6191901:**
+  the PC helper (ARM64, on the Frame itself, x264 test pattern) streamed
+  through a Mac SSH relay into the shared viewer: 400 frames at 39.3 fps,
+  content latency p50/p95 15.1/28.6 ms, synthetic input p50 76.6 ms, at
+  revision `cd20243`. The frame-rate and late-frame targets failed. This
+  proves the helper and the viewer work together; it isn't Windows capture or
+  a real PC link.
+  [Raw result](../bench/results/2026-09-28-cd20243-pc-agent-frame-arm64-final.json),
+  [earlier probe](../bench/results/2026-09-28-c5fc552-dirty-pc-agent-frame-arm64-hairpin.json).
+- **Verified, #38, on a Mac:** the C controller matched all 600 states of the
+  Swift controller's congestion and recovery trace.
+- **Not verified:** anything on a real Windows desktop. Windows.Graphics.Capture,
+  Media Foundation (hardware or software), encoder restarts when the bitrate
+  changes, mixed-DPI and multi-monitor input alignment, window resize and
+  minimise, non-US keyboard layouts, physical laser input, and how it performs
+  in a worn headset. No numbers are claimed for these. Not tested with a
+  headset from this branch.
+- **Not reviewed independently.** #38 tried an independent review that never
+  completed.

docs/recovery-and-images.md

@@ -4,6 +4,9 @@ Where to get the Steam Frame's operating system, what's inside it, and how to
 run it for testing without the headset. For recovering a Frame that won't boot,
 see the boot menu and boot-loop entries in
 [how-the-frame-works.md](how-the-frame-works.md#facts-worth-knowing).
+To keep your game saves, settings and Android app data through a factory reset
+(`Erase User Data`) or a re-image, and to get out of Desktop Mode, see
+[backup-and-recovery.md](backup-and-recovery.md).
 
 ## Downloads
 

docs/testing.md

@@ -187,6 +187,27 @@ refuses ids with a hyphen (`missing/invalid arguments`), which the fake had
 accepted. The fake now refuses them the same way, and Frame Control makes ids
 Steam accepts.
 
+## PC panel host tests
+
+PC in the headset (Experimental, Windows only). `tests/test_pcview.py` checks
+that only Windows gets the PC host and that it starts nothing until turned on,
+the Tools link and card wording, source-bound tickets, reconnect/Stop
+revocation, input release, source-coordinate mapping and use of the existing
+panel launcher. `tests/test_pc_controller.py` checks the C rate controller
+against a frozen trace of the Mac's Swift one.
+
+The `PC host libraries` workflow builds the native adapter on Windows (and
+the unshipped Linux adapter on Ubuntu x64 and ARM64), then runs a real x264
+synthetic stream through the HTTP/WebSocket agent. x264 is GPL, so only these
+CI builds include it (`desktop/build.py --with-x264`); the release workflow
+tests the installer's own bundle with its bundled Python and checks x264 isn't
+in it. `FRAME_PC_REQUIRE_NATIVE=1` and `FRAME_PC_REQUIRE_X264=1` make a missing
+bundle or encoder fail CI instead of skipping.
+
+None of this captures a desktop, exercises Media Foundation or a GPU, or
+checks laser alignment. The [Windows test VM](#windows-test-vm) is the next
+step for that. See [what's verified](pc-in-headset.md#whats-verified).
+
 ## Windows test VM
 
 The unit tests run on Windows in CI, but the app itself doesn't. Anything that
@@ -325,3 +346,14 @@ Chromium rendering and the same helper through HTTP. Close the switcher after
 testing. [The recorded device checks](panels.md#frame-controls-panel-switcher)
 cover actual focus, HTTP guards and an OpenXR sample transition, and separately
 identify the unverified Steam-game, spatial layout, reboot and laser behaviors.
+
+## Backup and recovery kit
+
+`tests/test_backup.py` runs the headset-side script `ui/frame_backup_remote.py`
+for real against a temporary folder laid out like the Frame's home, with only
+SSH faked: path selection and the secrets it must never copy, the manifest and
+checksums, restore checks after a reset, restore writing only its own files,
+unsafe archives and backup names, and the exact Game Mode command.
+`tests/e2e/test_recovery_kit.py` backs up and restores a Proton save on the fake
+Frame through the server. See [backup-and-recovery.md](backup-and-recovery.md#verification).
+No backup or restore has been run on a real headset yet.

scripts/macview-bench.py

@@ -55,6 +55,7 @@ from urllib.parse import quote, urlencode  # %20, not +: the agent's URLComponen
 ROOT = Path(__file__).resolve().parent.parent
 sys.path.insert(0, str(ROOT / "ui"))
 import frame_macview  # noqa: E402
+import frame_pcview  # noqa: E402
 
 RESULTS = ROOT / "bench" / "results"
 PAGES = ROOT / "bench" / "pages"
@@ -254,7 +255,10 @@ class LabView(frame_macview.MacView):
 
 def ssh_runner(base):
     def run(remote, stdin=None, timeout=30):
-        r = subprocess.run([*base, remote], input=stdin, capture_output=True, text=True, timeout=timeout)
+        r = subprocess.run([*base, remote], input=stdin.encode("utf-8") if stdin is not None else None,
+                           capture_output=True, timeout=timeout)
+        r.stdout = r.stdout.decode("utf-8", errors="replace")
+        r.stderr = r.stderr.decode("utf-8", errors="replace")
         if r.returncode:
             e = RuntimeError((r.stderr or r.stdout).strip())
             e.stdout = r.stdout
@@ -381,7 +385,11 @@ def run_scenario(args, scenario, agent_port, token, frame_ssh):
     if args.browser_flag is not None:
         mv.browser_flags = [f for f in args.browser_flag if f]
     chrome = None
-    src = "test"
+    src = args.source or "test"
+    cpu = None
+    if args.pc:
+        mv.host = "windows" if sys.platform == "win32" else "linux"
+        mv.viewer_profile = "pc-view"
     try:
         if scenario in ("scroll", "type"):
             chrome = chrome_window(f"{scenario}.html")
@@ -405,9 +413,10 @@ def run_scenario(args, scenario, agent_port, token, frame_ssh):
         since = max([f["s"] for f in first["frames"]] or [0])
         captured_before = first["captured"]
         start_mac_us = mv.call("/stats", id=stream["id"])["now"]
-        agent_pid = int(subprocess.run(["pgrep", "-f", "Frame Mac View Lab.app/Contents/MacOS/frame-mac-view"],
-                                       capture_output=True, text=True).stdout.split()[0])
-        cpu = CpuSampler(frame_ssh, agent_pid)
+        if not args.pc:
+            agent_pid = int(subprocess.run(["pgrep", "-f", "Frame Mac View Lab.app/Contents/MacOS/frame-mac-view"],
+                                           capture_output=True, text=True).stdout.split()[0])
+            cpu = CpuSampler(frame_ssh, agent_pid)
         if relay:
             relay.begin()
         expected = 0  # input events the harness asked the viewer for
@@ -443,7 +452,8 @@ def run_scenario(args, scenario, agent_port, token, frame_ssh):
         if not streams:
             raise SystemExit(f"{scenario}: the stream ended during the run (did the Frame go to sleep?)")
         data = streams[0]
-        cpu.stop()
+        if cpu:
+            cpu.stop()
         if args.raw:
             Path(f"{args.raw}-{scenario}.json").write_text(json.dumps(data))
         result = summarize(scenario, data, start_mac_us, end_mac_us, args, relay, schedule, expected)
@@ -452,7 +462,7 @@ def run_scenario(args, scenario, agent_port, token, frame_ssh):
                             for e in data.get("events", []) if e["t"] >= start_mac_us]
         result["captured"] = (captured_end if captured_end is not None else data["captured"]) - captured_before
         result["source_fps"] = round(result["captured"] / max(result["duration_s"], 1), 1)
-        result["cpu"] = cpu.summary()
+        result["cpu"] = cpu.summary() if cpu else {"host": "not sampled"}
         result["viewer"] = data["summary"].get("decoder", "")
         result["show_s"] = show_s
         result["panel"] = shown.get("panel")
@@ -460,6 +470,8 @@ def run_scenario(args, scenario, agent_port, token, frame_ssh):
         result["route"] = mv.route
         return result
     finally:
+        if cpu:
+            cpu.stop()
         try:
             mv.stop(src)
         except Exception:  # noqa: BLE001 - best effort
@@ -670,6 +682,8 @@ def fmt(v):
 
 def add_run_args(r):
     r.add_argument("--scenario", default="test,scroll,type")
+    r.add_argument("--pc", action="store_true", help="run the bundled PC host; use --scenario test or capture")
+    r.add_argument("--source", default="", help="PC source: window:ID, display:ID, or choose (Linux portal)")
     r.add_argument("--duration", type=float, default=20)
     r.add_argument("--warmup", type=float, default=3)
     r.add_argument("--quality", default="balanced", choices=list(frame_macview.QUALITY))
@@ -717,7 +731,7 @@ def frame_ssh_for(args):
 
 
 def run_suite(args, frame_ssh, quiet=False):
-    agent_port, token = lab_agent()
+    agent_port, token = (args.pc_view.port, args.pc_view.token) if args.pc else lab_agent()
     results = []
     for sc in args.scenario.split(","):
         if not quiet:
@@ -744,11 +758,12 @@ def document(args, frame_ssh, results, **extra):
     commit = git("rev-parse", "--short", "HEAD") + ("+dirty" if git("status", "--porcelain", "--", "mac", "ui") else "")
     return {
         "label": args.label or args.cmd, "date": datetime.datetime.now().isoformat(timespec="seconds"), "commit": commit,
-        "config": {"quality": args.quality, "mode": args.mode, "net": args.net or "none", "delay_ms": args.delay,
+        "config": {"quality": args.quality, "mode": "native" if args.pc else args.mode, "net": args.net or "none", "delay_ms": args.delay,
                    "buffer_ms": args.buffer, "host": args.host or args.frame, "usb": args.usb, "ssh_opts": args.ssh_opt,
                    "encoder": os.environ.get("FRAME_MAC_VIEW_ENCODER", ""), "duration_s": args.duration,
                    "browser_flags": args.browser_flag if args.browser_flag is not None else frame_macview.BROWSER_FLAGS},
-        "frame_build": build.strip().partition("=")[2], "mac": platform.mac_ver()[0], "headset": standby[-40:],
+        "frame_build": build.strip().partition("=")[2], "mac": platform.mac_ver()[0],
+        "host_platform": platform.platform(), "source": args.source, "pc_host": args.pc, "headset": standby[-40:],
         "scenarios": results, **extra,
     }
 
@@ -819,19 +834,46 @@ def main():
             print("\nworse:\n  " + "\n  ".join(regs))
         sys.exit(1 if regs else 0)
 
-    lab_agent()
+    if args.pc and (args.cmd == "ab" or args.scenario not in ("test", "capture")):
+        p.error("PC runs use --scenario test or --scenario capture; Mac automation is not portable")
+    if args.pc and args.scenario == "capture" and not args.source:
+        p.error("capture needs --source window:ID, display:ID, or choose")
+    if not args.pc:
+        lab_agent()
     frame_ssh = frame_ssh_for(args)
     # Keep the Mac's screen awake: virtual displays aren't removed while it sleeps.
     runs = 1 if args.cmd == "run" else args.repeat * len(args.arm)
-    awake = subprocess.Popen(["caffeinate", "-d", "-u", "-t", str(int(runs * (args.duration * 4 + 60) + 120))])
+    awake = subprocess.Popen(["caffeinate", "-d", "-u", "-t", str(int(runs * (args.duration * 4 + 60) + 120))]) if sys.platform == "darwin" else None
+    args.pc_view = None
     try:
+        if args.pc:
+            args.pc_view = frame_pcview.PCView(frame_ssh[:-1], ssh_runner(frame_ssh), frame_ssh[-1])
+            args.pc_view.ensure_agent()
+            if args.source == "choose":
+                args.pc_view.call("/permissions", method="POST")
+                print("Choose a window or screen in your desktop's sharing dialog.", flush=True)
+                deadline = time.monotonic()+125
+                while time.monotonic() < deadline:
+                    state = args.pc_view.call("/status")
+                    if not state.get("selecting"):
+                        sources = args.pc_view.call("/windows")["windows"]
+                        if not sources:
+                            raise SystemExit(state.get("selectionError") or "Nothing was shared")
+                        args.source = sources[-1]["src"]
+                        break
+                    time.sleep(.5)
+                else:
+                    raise SystemExit("Sharing dialog timed out")
         if args.cmd == "ab":
             arm_runs, table = ab(args, frame_ssh)
             write(document(args, frame_ssh, [], arms=args.arm, runs=arm_runs, table=table), args)
             return
         results = run_suite(args, frame_ssh)
     finally:
-        awake.terminate()
+        if args.pc_view:
+            args.pc_view.shutdown()
+        if awake:
+            awake.terminate()
     doc = document(args, frame_ssh, results)
     write(doc, args)
     bad = [f"{r['scenario']} {k}" for r in results for k, v in r["grades"].items() if v in ("bad", "missing")]

tests/e2e/test_recovery_kit.py

@@ -0,0 +1,55 @@
+"""Backup and recovery kit through the server against the fake Frame: a Proton game's save
+goes to this computer and back, Steam's sign-in token never leaves the headset."""
+import json
+import shutil
+import tarfile
+import unittest
+from pathlib import Path
+
+import harness
+from harness import api, finished, ok, ssh
+
+harness.require()
+
+SAVE = '.local/share/Steam/steamapps/compatdata/620980/pfx/drive_c/users/steamuser/AppData/LocalLow/Beat Games/Beat Saber/PlayerData.dat'
+
+
+class Backup(harness.FrameTestCase):
+    def test_saves_round_trip_and_secrets_stay(self):
+        ssh(f"mkdir -p ~/'{Path(SAVE).parent}' && printf 'level 7' > ~/'{SAVE}' && "
+            "mkdir -p ~/.steam && printf SECRET > ~/.steam/steam.token")
+        job = finished(ok('POST', '/api/backup', {'action': 'backup', 'kinds': ['saves', 'settings']}), 120)
+        self.assertIsNone(job['error'], job)
+        folder = Path(job['result']['path'])
+        self.addCleanup(shutil.rmtree, str(folder), True)
+        manifest = json.loads((folder / 'manifest.json').read_text())
+        self.assertEqual(manifest['headset']['build'], '20260922.6101926')
+        saves = next(p for p in manifest['parts'] if p['id'] == 'saves:620980')
+        self.assertEqual(saves['label'], 'Beat Saber saves')
+        self.assertEqual([f['path'] for f in saves['files']], [SAVE])
+        for part in manifest['parts']:
+            with tarfile.open(str(folder / part['archive'])) as tar:
+                self.assertFalse([m.name for m in tar if 'steam.token' in m.name])
+        self.assertEqual(ssh('cat ~/.steam/steam.token'), 'SECRET')  # read-only on the headset
+
+        ssh(f"rm ~/'{SAVE}'")
+        name = folder.name
+        plan = {p['id']: p for p in ok('POST', '/api/backup', {'action': 'plan', 'name': name})['parts']}
+        self.assertEqual((plan['saves:620980']['status'], plan['saves:620980']['new']), ('ok', 1))
+        status, out, _ = api('POST', '/api/backup', {'action': 'restore', 'name': name, 'parts': ['saves:620980']})
+        self.assertEqual(status, 400, out)  # not confirmed
+        job = finished(ok('POST', '/api/backup', {'action': 'restore', 'name': name, 'parts': ['saves:620980'],
+                                                  'confirm': True}), 120)
+        self.assertIsNone(job['error'], job)
+        self.assertEqual(ssh(f"cat ~/'{SAVE}'"), 'level 7')
+
+    def test_bad_names_and_session(self):
+        status, out, _ = api('POST', '/api/backup', {'action': 'plan', 'name': '../../etc'})
+        self.assertEqual(status, 400, out)
+        state = ok('POST', '/api/backup', {'action': 'session'})
+        self.assertIn(state['mode'], ('game', 'desktop', 'unknown'))
+        self.assertIsNone(state['selector'])  # the fake has no session switch command
+
+
+if __name__ == '__main__':
+    unittest.main()

tests/test_backup.py

@@ -0,0 +1,450 @@
+"""Backup and recovery kit (ui/frame_backup.py, ui/frame_backup_remote.py) against a folder laid
+out like the Frame's home. The headset-side script runs for real, locally; only SSH is faked."""
+import sandbox  # noqa: F401  (first: keeps tests off real data and services)
+import io
+import json
+import os
+from pathlib import Path
+import shlex
+import subprocess
+import sys
+import tarfile
+import tempfile
+import unittest
+from unittest.mock import patch
+
+ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(ROOT / 'ui'))
+import frame_android as android  # noqa: E402
+import frame_backup as backup  # noqa: E402
+import frame_backup_remote as remote  # noqa: E402
+import server  # noqa: E402
+
+STEAM = '.local/share/Steam'
+USER = STEAM + '/steamapps/compatdata/%s/pfx/drive_c/users/steamuser'
+SECRETS = ['.steam/steam.token', STEAM + '/config/config.vdf', STEAM + '/config/loginusers.vdf',
+           STEAM + '/ssfn123456', '.ssh/id_ed25519', '.ssh/authorized_keys',
+           USER % 1234 + '/AppData/Roaming/Launcher/session.token',
+           USER % 1234 + '/AppData/Roaming/Launcher/.ssh/id_rsa',
+           '.config/cliproxyapi/secrets.env', '.local/share/keyrings/login.keyring']
+
+
+def write(home, rel, data=b'x'):
+    path = Path(home) / rel
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_bytes(data if isinstance(data, bytes) else data.encode())
+    return path
+
+
+def manifest(home, appid, name):
+    write(home, '%s/steamapps/appmanifest_%s.acf' % (STEAM, appid),
+          '"AppState"\n{\n\t"appid"\t\t"%s"\n\t"name"\t\t"%s"\n}\n' % (appid, name))
+
+
+def frame_home(home):
+    """A Frame before a reset: one Proton game, a Linux game, settings and secrets."""
+    manifest(home, 1234, 'Test Game')
+    write(home, USER % 1234 + '/AppData/Roaming/Studio/Game/save1.dat', b'save one')
+    write(home, USER % 1234 + '/Documents/My Games/Game/profile.sav', b'profile')
+    write(home, USER % 1234 + '/AppData/Local/Temp/junk.tmp', b'junk')
+    write(home, USER % 1234 + '/AppData/Local/Microsoft/Windows/x.db', b'wine')
+    write(home, USER % 999 + '/AppData/Local/Temp/only-cache', b'c')        # no saves: no part
+    write(home, STEAM + '/steamapps/compatdata/2800000001/internal/org.example/x', b'android')
+    write(home, STEAM + '/userdata/555/config/localconfig.vdf', b'local')
+    write(home, STEAM + '/userdata/555/config/shortcuts.vdf', b'shortcuts')
+    write(home, STEAM + '/userdata/555/241100/remote/controller_config/1234/layout.vdf', b'layout')
+    write(home, STEAM + '/userdata/555/1234/remote/cloud.sav', b'cloud')    # Steam Cloud's own
+    write(home, STEAM + '/userdata/555/760/remote/1234/screenshots/a.jpg', b'shot')
+    write(home, '.config/kdeglobals', b'[General]')
+    write(home, '.config/openvr/config/steamvr.vrsettings', b'{}')
+    write(home, '.config/unity3d/Company/LinuxGame/prefs', b'prefs')
+    write(home, '.bashrc', b'# mine')
+    for rel in SECRETS:
+        write(home, rel, b'SECRET')
+
+
+class Remote(unittest.TestCase):
+    def setUp(self):
+        self.tmp = tempfile.TemporaryDirectory()
+        self.home = Path(self.tmp.name)
+        patcher = patch.object(remote, 'HOME', self.home)
+        patcher.start()
+        self.addCleanup(patcher.stop)
+        self.addCleanup(self.tmp.cleanup)
+
+    def files(self, part):
+        return [rel for rel, _ in remote.part_files(part)[0]]
+
+    def test_plan_picks_saves_and_settings_and_never_secrets(self):
+        frame_home(self.home)
+        plan = remote.plan()
+        ids = [p['id'] for p in plan['parts']]
+        self.assertEqual(ids, ['saves:1234', 'saves:linux', 'settings:steam', 'settings:system'])
+        self.assertEqual(plan['parts'][0]['label'], 'Test Game saves')
+        saves = self.files('saves:1234')
+        self.assertEqual(sorted(saves), [USER % 1234 + '/AppData/Roaming/Studio/Game/save1.dat',
+                                         USER % 1234 + '/Documents/My Games/Game/profile.sav'])
+        steam = self.files('settings:steam')
+        self.assertIn(STEAM + '/userdata/555/241100/remote/controller_config/1234/layout.vdf', steam)
+        self.assertIn(STEAM + '/userdata/555/config/localconfig.vdf', steam)
+        self.assertFalse([f for f in steam if '/1234/remote/' in f or '/760/' in f])
+        everything = sum((self.files(i) for i in ids), [])
+        for rel in SECRETS + ['.bashrc']:
+            self.assertNotIn(rel, everything)
+        self.assertFalse([f for f in everything if remote.is_secret(f)])
+        self.assertTrue(any('steam.token' in x for x in plan['excluded']))
+        # The controller layout goes back; localconfig.vdf and shortcuts.vdf are for reference.
+        steam_part = plan['parts'][2]
+        self.assertEqual((steam_part['files'], steam_part['restorable']), (3, 1))
+
+    def test_secret_names(self):
+        for rel in SECRETS + ['a/b/ID_RSA.pub', 'x/kwalletd/k', 'x/cert.PEM']:
+            self.assertTrue(remote.is_secret(rel), rel)
+        for rel in ['saves/game.sav', 'Documents/tokens-collected.txt', 'config/localconfig.vdf']:
+            self.assertFalse(remote.is_secret(rel), rel)
+
+    @unittest.skipIf(os.name == 'nt', 'symlinks need privileges on Windows')
+    def test_links_are_never_followed(self):
+        frame_home(self.home)
+        outside = write(self.home, 'elsewhere/private.txt', b'p')
+        base = self.home / (USER % 1234) / 'Documents'
+        os.symlink(str(outside.parent), str(base / 'linked-dir'))
+        os.symlink(str(outside), str(base / 'linked-file'))
+        self.assertFalse([f for f in self.files('saves:1234') if 'linked' in f])
+
+    def test_big_files_are_listed_as_skipped(self):
+        frame_home(self.home)
+        with patch.object(remote, 'MAX_FILE', 3):
+            files, skipped = remote.part_files('saves:1234')
+        self.assertEqual(files, [])
+        self.assertEqual({s['reason'] for s in skipped}, {'over 2 GiB'})
+
+    def test_pack_holds_exactly_the_planned_files(self):
+        frame_home(self.home)
+        out = io.BytesIO()
+        remote.pack('saves:1234', out)
+        out.seek(0)
+        with tarfile.open(fileobj=out, mode='r:gz') as archive:
+            names = sorted(m.name for m in archive)
+        self.assertEqual(names, sorted(self.files('saves:1234')))
+        with self.assertRaises(ValueError):
+            remote.pack('saves:../../etc', io.BytesIO())
+
+    def archive(self, members):
+        out = io.BytesIO()
+        with tarfile.open(fileobj=out, mode='w:gz') as tar:
+            for name, data in members:
+                info = tarfile.TarInfo(name)
+                info.size = len(data)
+                tar.addfile(info, io.BytesIO(data))
+        out.seek(0)
+        return out
+
+    def test_check_after_a_reset(self):
+        save = USER % 1234 + '/AppData/Roaming/Studio/Game/save1.dat'
+        ask = {'parts': [{'id': 'saves:1234', 'files': [save]},
+                         {'id': 'settings:steam', 'files': [STEAM + '/userdata/555/241100/remote/controller_config/1/a.vdf']},
+                         {'id': 'settings:system', 'files': ['.config/openvr/config/steamvr.vrsettings']},
+                         {'id': 'saves:../x', 'files': []}]}
+        states = lambda: [p['status'] for p in remote.check(ask)['parts']]  # noqa: E731
+        self.assertEqual(states(), ['not_installed', 'no_account', 'reference', 'unknown'])
+        manifest(self.home, 1234, 'Test Game')
+        (self.home / STEAM / 'userdata/555').mkdir(parents=True)
+        self.assertEqual(states()[:2], ['no_prefix', 'ok'])
+        (self.home / (USER % 1234)).mkdir(parents=True)
+        result = remote.check(ask)['parts'][0]
+        self.assertEqual((result['status'], result['new'], result['replace']), ('ok', 1, 0))
+        write(self.home, save, b'newer')
+        self.assertEqual(remote.check(ask)['parts'][0]['replace'], 1)
+
+    def test_restore_replaces_only_its_files_and_keeps_the_old_ones(self):
+        manifest(self.home, 1234, 'Test Game')
+        save = USER % 1234 + '/AppData/Roaming/Studio/Game/save1.dat'
+        write(self.home, save, b'played since')
+        other = write(self.home, USER % 1234 + '/AppData/Roaming/Studio/Game/other.dat', b'untouched')
+        bashrc = write(self.home, '.bashrc', b'# mine')
+        source = self.archive([(save, b'from backup'), (USER % 1234 + '/Documents/new.sav', b'new'),
+                               ('.bashrc', b'# replaced?')])
+        result = remote.restore('saves:1234', '20261023-120000', source)
+        self.assertEqual((result['written'], result['replaced']), (2, 1))
+        self.assertEqual(result['held'], {'reference': 1})
+        self.assertEqual((self.home / save).read_bytes(), b'from backup')
+        self.assertEqual(other.read_bytes(), b'untouched')
+        self.assertEqual(bashrc.read_bytes(), b'# mine')
+        kept = self.home / remote.PREVIOUS / '20261023-120000' / save
+        self.assertEqual(kept.read_bytes(), b'played since')
+        self.assertFalse([p for p in (self.home / save).parent.iterdir() if p.name.endswith('.part')])
+
+    def test_unsafe_archives_write_nothing(self):
+        manifest(self.home, 1234, 'Test Game')
+        (self.home / (USER % 1234)).mkdir(parents=True)
+        good = (USER % 1234 + '/Documents/a.sav', b'a')
+        for bad in ('../escape', '/etc/passwd', USER % 1234 + '/Documents/../../../../../../x',
+                    USER % 1234 + '/Documents/a.sav'):
+            with self.assertRaises(ValueError, msg=bad):
+                remote.restore('saves:1234', '20261023-120000', self.archive([good, (bad, b'evil')]))
+            self.assertFalse((self.home / good[0]).exists(), bad)
+        link = io.BytesIO()
+        with tarfile.open(fileobj=link, mode='w:gz') as tar:
+            info = tarfile.TarInfo(USER % 1234 + '/Documents/l')
+            info.type, info.linkname = tarfile.SYMTYPE, '/etc/passwd'
+            tar.addfile(info)
+        link.seek(0)
+        with self.assertRaises(ValueError):
+            remote.restore('saves:1234', '20261023-120000', link)
+        with self.assertRaises(ValueError):
+            remote.restore('saves:1234', '../stamp', self.archive([good]))
+
+    def test_restore_refuses_secrets_and_other_games(self):
+        manifest(self.home, 1234, 'Test Game')
+        (self.home / (USER % 1234)).mkdir(parents=True)
+        result = remote.restore('saves:1234', '20261023-120000', self.archive([
+            (USER % 1234 + '/AppData/Roaming/L/auth.token', b't'), (USER % 5678 + '/Documents/x.sav', b'x')]))
+        self.assertEqual(result['written'], 0)
+        self.assertEqual(result['held'], {'refused': 1, 'reference': 1})
+
+    def test_session_reads_the_mode(self):
+        conf = write(self.home, 'zz-steamos-autologin.conf', '[Autologin]\nSession=plasma-steamos-wayland-oneshot.desktop\n')
+        running = set()
+        with patch.object(remote, 'SDDM_CONFS', (str(conf),)), \
+                patch.object(remote, '_running', side_effect=lambda n, full=False: n in running), \
+                patch.object(remote.shutil, 'which', side_effect=lambda n: '/usr/bin/' + n if n == 'steamos-session-select' else None):
+            state = remote.session()
+            self.assertEqual((state['mode'], state['selector']), ('desktop', 'steamos-session-select'))
+            self.assertEqual(state['configured'], 'plasma-steamos-wayland-oneshot.desktop')
+            running.update({'gamescope', 'plasmashell'})  # the nested desktop panel
+            self.assertEqual(remote.session()['mode'], 'game')
+            running.clear()
+            running.add('gamescope-wl')  # gamescope's process name on the Frame, with no desktop panel open
+            self.assertEqual(remote.session()['mode'], 'game')
+            running.clear()
+            running.add('start-gamescope-session')
+            self.assertEqual(remote.session()['mode'], 'game')
+
+
+def fake_ssh(home, os_release):
+    """Runs the headset-side command locally, as the Frame's python3 would."""
+    def run(command, src=None, dst=None, timeout=None):
+        argv = shlex.split(command)
+        assert argv[:2] == ['python3', '-c'], argv
+        data = src if isinstance(src, bytes) else src.read() if src is not None else b''
+        env = dict(os.environ, FRAME_BACKUP_HOME=str(home), FRAME_BACKUP_OS_RELEASE=str(os_release))
+        r = subprocess.run([sys.executable, *argv[1:]], input=data, capture_output=True, env=env)
+        if r.returncode:
+            raise backup.BackupError(r.stderr.decode(errors='replace'))
+        if dst is not None:
+            dst.write(r.stdout)
+            return None
+        return r.stdout
+    return run
+
+
+class Local(unittest.TestCase):
+    def setUp(self):
+        self.tmp = tempfile.TemporaryDirectory()
+        self.addCleanup(self.tmp.cleanup)
+        base = Path(self.tmp.name)
+        self.home, self.store = base / 'frame', base / 'backups'
+        self.release = write(base, 'os-release', 'ID=steamos\nVERSION_ID=0.4.1\nBUILD_ID=20260925.6191901\n')
+        frame_home(self.home)
+        for p in (patch.dict(os.environ, FRAME_BACKUP_DIR=str(self.store)),
+                  patch.object(backup, '_ssh', side_effect=fake_ssh(self.home, self.release))):
+            p.start()
+            self.addCleanup(p.stop)
+
+    def android_backup(self, package, destination):
+        write(Path(destination).parent, Path(destination).name, b'android archive ' + package.encode())
+        return {'package': package, 'instance': android.instance_id(package), 'files': 3, 'bytes': 42,
+                'path': str(destination), 'sha256': backup._sha256(destination)}
+
+    def make(self):
+        apps = [{'package': 'org.example.open', 'label': 'Open app', 'running': True},
+                {'package': 'org.example.game', 'label': 'Game', 'running': False}]
+        with patch.object(android, 'list_apps', return_value=apps), \
+                patch.object(android, 'backup_data', side_effect=self.android_backup) as data, \
+                patch.object(backup.time, 'strftime', side_effect=lambda f: '2026-10-23-120000' if f == '%Y-%m-%d-%H%M%S'
+                             else '2026-10-23T12:00:00+0100'):
+            result = backup.backup(headset='My Frame')
+        data.assert_called_once()
+        return result
+
+    def test_backup_writes_a_manifest_with_checksums(self):
+        result = self.make()
+        folder = backup.backup_path('2026-10-23-120000')  # resolved: macOS's temp folder is a link
+        self.assertEqual(result['path'], str(folder))
+        self.assertEqual(sorted(p.name for p in self.store.iterdir()), ['2026-10-23-120000'])  # no .partial left
+        m = json.loads((folder / 'manifest.json').read_text())
+        self.assertEqual(m['headset'], {'name': 'My Frame', 'build': '20260925.6191901', 'version': '0.4.1'})
+        self.assertEqual([p['id'] for p in m['parts']],
+                         ['saves:1234', 'saves:linux', 'settings:steam', 'settings:system', 'android:org.example.game'])
+        for part in m['parts']:
+            self.assertEqual(backup._sha256(folder / part['archive']), part['sha256'])
+        saves = m['parts'][0]
+        self.assertEqual(saves['archive'], 'saves/saves-1234.tar.gz')
+        self.assertEqual(sum(f['bytes'] for f in saves['files']), saves['bytes'])
+        self.assertEqual(saves['files'][0]['sha256'], __import__('hashlib').sha256(b'save one').hexdigest())
+        self.assertEqual([s['id'] for s in m['skipped']], ['android:org.example.open'])
+        for part in m['parts'][:-1]:
+            with tarfile.open(str(folder / part['archive'])) as tar:
+                for member in tar:
+                    self.assertFalse(remote.is_secret(member.name), member.name)
+                    self.assertNotEqual(tar.extractfile(member).read(), b'SECRET', member.name)
+
+    def test_a_failed_backup_leaves_nothing_behind(self):
+        with patch.object(backup, 'inspect_archive', side_effect=backup.BackupError('cut off')), \
+                patch.object(android, 'list_apps', return_value=[]):
+            with self.assertRaises(backup.BackupError):
+                backup.backup(kinds=['saves'])
+        self.assertEqual(list(self.store.iterdir()), [])
+
+    def test_backup_names_cannot_leave_the_folder(self):
+        for name in ('../2026-10-23-120000', '2026-10-23-120000/..', '..', '/etc', 'C:\\x', '',
+                     '2026-10-23-120000/../../x', '2026-10-23-12000', None, 5):
+            with self.assertRaises(backup.BackupError, msg=repr(name)):
+                backup.backup_path(name)
+        self.assertEqual(backup.backup_path('2026-10-23-120000'), (self.store / '2026-10-23-120000').resolve())
+
+    def test_manifest_entries_cannot_point_outside_the_backup(self):
+        self.make()
+        path = self.store / '2026-10-23-120000' / 'manifest.json'
+        m = json.loads(path.read_text())
+        for archive in ('../../secret.tar.gz', '/etc/passwd', 'saves/saves-5678.tar.gz'):
+            m['parts'][0]['archive'] = archive
+            path.write_text(json.dumps(m))
+            with self.assertRaises(backup.BackupError, msg=archive):
+                backup.read_manifest('2026-10-23-120000')
+
+    def reset(self):
+        """A factory reset: the home folder is empty again."""
+        import shutil
+        shutil.rmtree(str(self.home))
+        self.home.mkdir()
+
+    def test_restore_after_a_reset_skips_what_is_not_back_yet(self):
+        self.make()
+        self.reset()
+        manifest(self.home, 1234, 'Test Game')
+        (self.home / (USER % 1234)).mkdir(parents=True)  # started once
+        with patch.object(android, 'list_apps', return_value=[]):
+            plan = {p['id']: p for p in backup.restore_plan('2026-10-23-120000')['parts']}
+            self.assertEqual(plan['saves:1234']['status'], 'ok')
+            self.assertEqual(plan['settings:steam']['status'], 'no_account')
+            self.assertEqual(plan['android:org.example.game']['status'], 'not_installed')
+            with self.assertRaises(backup.BackupError):
+                backup.restore('2026-10-23-120000', ['saves:1234'])  # not confirmed
+            self.assertFalse((self.home / (USER % 1234) / 'AppData').exists())
+            result = backup.restore('2026-10-23-120000', ['saves:1234', 'settings:steam', 'android:org.example.game'],
+                                    confirmed=True)
+        self.assertEqual([r['id'] for r in result['restored']], ['saves:1234'])
+        self.assertEqual({s['id'] for s in result['skipped']}, {'settings:steam', 'android:org.example.game'})
+        self.assertEqual((self.home / (USER % 1234) / 'AppData/Roaming/Studio/Game/save1.dat').read_bytes(), b'save one')
+
+    def test_android_data_goes_back_through_the_existing_helper(self):
+        self.make()
+        apps = [{'package': 'org.example.game', 'label': 'Game', 'running': False}]
+        with patch.object(android, 'list_apps', return_value=apps), \
+                patch.object(android, 'restore_data', return_value={'restored': True}) as restore:
+            result = backup.restore('2026-10-23-120000', ['android:org.example.game'], confirmed=True)
+        restore.assert_called_once_with('org.example.game', str(backup.backup_path('2026-10-23-120000') /
+                                                                 'android' / 'org.example.game.tar.gz'))
+        self.assertEqual(len(result['restored']), 1)
+        apps[0]['running'] = True
+        with patch.object(android, 'list_apps', return_value=apps), patch.object(android, 'restore_data') as restore:
+            result = backup.restore('2026-10-23-120000', ['android:org.example.game'], confirmed=True)
+        restore.assert_not_called()
+        self.assertEqual(result['skipped'][0]['reason'], 'Close the app first')
+
+    def test_a_damaged_archive_is_skipped(self):
+        self.make()
+        with open(str(self.store / '2026-10-23-120000/saves/saves-1234.tar.gz'), 'ab') as f:
+            f.write(b'tampered')
+        with patch.object(android, 'list_apps', return_value=[]):
+            result = backup.restore('2026-10-23-120000', ['saves:1234'], confirmed=True)
+        self.assertEqual(result['restored'], [])
+        self.assertIn('checksum', result['skipped'][0]['reason'])
+
+    def test_list_backups(self):
+        self.make()
+        (self.store / '.2026-10-23-130000.partial').mkdir()
+        (self.store / 'notes').mkdir()
+        listed = backup.list_backups()['backups']
+        self.assertEqual([b['name'] for b in listed], ['2026-10-23-120000'])
+        self.assertEqual(listed[0]['build'], '20260925.6191901')
+
+
+class Ssh(unittest.TestCase):
+    def test_bytes_go_as_input_and_files_as_stdin(self):
+        done = subprocess.CompletedProcess([], 0, b'{}', b'')
+        with patch.object(backup.frame_host, 'run_ssh', return_value=done) as run:
+            backup._ssh('true', src=b'{"parts": []}')
+            self.assertEqual(run.call_args.kwargs['input'], b'{"parts": []}')
+            self.assertNotIn('stdin', run.call_args.kwargs)
+            with tempfile.TemporaryFile() as f:
+                backup._ssh('true', src=f)
+                self.assertIs(run.call_args.kwargs['stdin'], f)
+            backup._ssh('true')
+            self.assertIs(run.call_args.kwargs['stdin'], subprocess.DEVNULL)
+            self.assertEqual(run.call_args.args[0][-1], 'true')
+        with patch.object(backup.frame_host, 'run_ssh',
+                          return_value=subprocess.CompletedProcess([], 1, b'', b'Permission denied')):
+            with self.assertRaisesRegex(backup.BackupError, 'Permission denied'):
+                backup._ssh('true')
+
+
+class GameMode(unittest.TestCase):
+    def test_command_is_only_ever_the_session_switch(self):
+        self.assertEqual(backup.session_command('steamos-session-select'), 'steamos-session-select gamescope')
+        self.assertEqual(backup.session_command('holo-session-select'), 'holo-session-select gamescope')
+        for bad in (None, '', 'rm -rf ~', '/tmp/steamos-session-select', 'steamos-session-select; reboot'):
+            with self.assertRaises(backup.BackupError):
+                backup.session_command(bad)
+
+    def test_switch_needs_confirmation_and_desktop_mode(self):
+        with patch.object(backup, '_ssh') as ssh:
+            with self.assertRaises(backup.BackupError):
+                backup.return_to_game_mode()
+            ssh.assert_not_called()
+        with patch.object(backup, 'session_status', return_value={'mode': 'game', 'selector': 'steamos-session-select'}), \
+                patch.object(backup, '_ssh') as ssh:
+            self.assertFalse(backup.return_to_game_mode(confirmed=True)['switched'])
+            ssh.assert_not_called()
+        with patch.object(backup, 'session_status', return_value={'mode': 'unknown', 'selector': 'steamos-session-select'}), \
+                patch.object(backup, '_ssh') as ssh:
+            with self.assertRaisesRegex(backup.BackupError, 'nothing was changed'):
+                backup.return_to_game_mode(confirmed=True)
+            ssh.assert_not_called()
+        with patch.object(backup, 'session_status', return_value={'mode': 'desktop', 'selector': 'steamos-session-select'}), \
+                patch.object(backup, '_ssh') as ssh:
+            self.assertTrue(backup.return_to_game_mode(confirmed=True)['switched'])
+            ssh.assert_called_once_with('steamos-session-select gamescope', timeout=60)
+            ssh.side_effect = backup.BackupError('the headset took too long to answer')  # the session restarted
+            self.assertTrue(backup.return_to_game_mode(confirmed=True)['switched'])
+            ssh.side_effect = backup.BackupError('Interactive authentication required')
+            with self.assertRaisesRegex(backup.BackupError, 'manual steps'):
+                backup.return_to_game_mode(confirmed=True)
+        with patch.object(backup, 'session_status', return_value={'mode': 'desktop', 'selector': None}), \
+                patch.object(backup, '_ssh') as ssh:
+            with self.assertRaises(backup.BackupError):
+                backup.return_to_game_mode(confirmed=True)
+            ssh.assert_not_called()
+
+
+class Endpoint(unittest.TestCase):
+    def test_guards_run_before_the_headset(self):
+        with patch.object(backup, '_ssh') as ssh, patch.object(server, 'start_job') as job:
+            for body in ({'action': 'plan', 'name': '../x'}, {'action': 'open', 'name': '..'},
+                         {'action': 'restore', 'name': '2026-10-23-120000', 'parts': ['saves:1234']},
+                         {'action': 'restore', 'name': '2026-10-23-120000', 'parts': ['saves:x'], 'confirm': True},
+                         {'action': 'gamemode'}, {'action': 'backup', 'kinds': ['ssh-keys']}, {'action': 'nope'}):
+                with self.assertRaises(server.Failure, msg=body) as caught:
+                    server.backup_action(body)
+                self.assertEqual(caught.exception.status, 400)
+            ssh.assert_not_called()
+            job.assert_not_called()
+            with patch.object(server, 'LOCAL', True):
+                with self.assertRaises(server.Failure):
+                    server.backup_action({'action': 'list'})
+
+
+if __name__ == '__main__':
+    unittest.main()

tests/test_macview.py

@@ -84,7 +84,10 @@ class Helpers(unittest.TestCase):
     @unittest.skipUnless(shutil.which("bash"), "needs bash")
     @unittest.skipIf(os.name == "nt", "Windows' bash.exe is WSL's launcher, and runners have no distribution")
     def test_launch_script_parses(self):
-        r = subprocess.run(["bash", "-n"], input=frame_macview.LAUNCH, text=True, capture_output=True)
+        bash = str(Path(os.environ.get("ProgramFiles", "C:/Program Files")) / "Git/bin/bash.exe") if sys.platform == "win32" else "bash"
+        if sys.platform == "win32" and not Path(bash).exists():
+            self.skipTest("Git Bash is not installed (WSL bash is not a local shell)")
+        r = subprocess.run([bash, "-n"], input=frame_macview.LAUNCH.encode("utf-8"), capture_output=True)
         self.assertEqual(r.returncode, 0, r.stderr)
 
     def test_show_checks_the_source_before_anything_else(self):

tests/test_page_startup.py

@@ -9,7 +9,7 @@ import subprocess
 import unittest
 
 ROOT = pathlib.Path(__file__).resolve().parents[1]
-STUBS = ['$', 'toggleLive', 'scrollToY', 'scroller', 'loadMacView', 'loadPanels', 'loadPanelSwitcher', 'loadTitles', 'showAndroidTab',
+STUBS = ['$', 'toggleLive', 'scrollToY', 'scroller', 'loadMacView', 'loadPanels', 'loadPanelSwitcher', 'loadBackups', 'loadTitles', 'showAndroidTab',
          'loadAndroid', 'loadDisplays', 'setGameSource', 'requestAnimationFrame']
 
 RUN = r'''

tests/test_pc_controller.py

@@ -0,0 +1,64 @@
+"""Frozen regression trace from the original mac-in-headset Swift controller.
+The 600-state reference was produced at 1b90c64, before the C extraction:
+60 seconds with a slow/congested middle, then recovery. No generated behavior
+from the new implementation is used to calculate the expected digest.
+"""
+import ctypes as C
+import hashlib
+import json
+from pathlib import Path
+import shutil
+import subprocess
+import sys
+import tempfile
+import unittest
+
+ROOT = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(ROOT / 'ui'))
+from frame_pc_capture import Controller
+
+
+class ControllerTrace(unittest.TestCase):
+    def test_original_mac_congestion_and_recovery(self):
+        cc = shutil.which('cc') or shutil.which('gcc')
+        if not cc:
+            self.skipTest('C compiler not installed; native build jobs cover this trace')
+        with tempfile.TemporaryDirectory() as tmp:
+            path = Path(tmp) / ('trace.dll' if sys.platform == 'win32' else 'trace.so')
+            subprocess.run([cc, '-O2', '-shared', '-fPIC', str(ROOT/'desktop/controller.c'), '-o', str(path)], check=True, capture_output=True)
+            lib = C.CDLL(str(path))
+            sig = {'new': (C.c_void_p, [C.c_int, C.c_int]), 'free': (None, [C.c_void_p]),
+                   'ceiling': (None, [C.c_void_p, C.c_int]), 'value': (C.c_int64, [C.c_void_p, C.c_int]),
+                   'capture': (None, [C.c_void_p, C.c_int64]), 'gate': (C.c_int, [C.c_void_p, C.c_int64, C.c_int]),
+                   'sent': (None, [C.c_void_p, C.c_uint32, C.c_int, C.c_int64]),
+                   'ack': (C.c_int, [C.c_void_p, C.c_uint32, C.c_int64]), 'update': (C.c_int, [C.c_void_p, C.c_int64])}
+            for name, (ret, args) in sig.items():
+                fn = getattr(lib, 'fc_'+name)
+                fn.restype, fn.argtypes = ret, args
+            c = Controller(lib, 60, 8000000)
+            due, states, seq = [], [], 0
+            try:
+                for tick in range(6000):
+                    now = 10000000+tick*10000
+                    for t, s in due:
+                        if t <= now:
+                            c.call('ack', s, now)
+                    due = [(t, s) for t, s in due if t > now]
+                    if tick % 2 == 0:
+                        c.call('capture', now)
+                        if c.call('gate', now, 1):
+                            seq += 1
+                            c.call('sent', seq, 8000 if tick < 1000 or tick > 4000 else 22000, now)
+                            due.append((now+(240000 if 1500 < tick < 3500 else 20000), seq))
+                    if tick % 10 == 0:
+                        c.update(now)
+                        x = c.state()
+                        states.append([x[k] for k in ('target', 'ceiling', 'tier', 'fps', 'inFlight')] +
+                                      [round(x['scale']*100), round(x['baseRtt']*1000), round(x['slack']*1000)])
+                digest = hashlib.sha256(json.dumps(states, separators=(',', ':')).encode()).hexdigest()
+                self.assertEqual(digest, '1932f16aafce5c9157bcd2aba5d90719a366f9999422920aaeae78a6cdec08f6')
+            finally:
+                c.close()
+                if sys.platform == 'win32':
+                    import _ctypes
+                    _ctypes.FreeLibrary(lib._handle)

tests/test_pcview.py

@@ -0,0 +1,520 @@
+"""PC adapters: grants, input cleanup, launcher reuse and native codec contract.
+Native tests require the bundled libraries; CI sets REQUIRE_NATIVE so a missing
+bundle is a failure, never a silent skip. No desktop consent or GPU is faked as
+successful real-host capture.
+
+The encoding tests need x264, which only CI's own builds bundle (it's GPL, so
+the installer leaves it out). FRAME_PC_REQUIRE_X264=1 makes its absence a
+failure; FRAME_PC_INSTALLER_BUNDLE=1 checks the installer's bundle instead.
+"""
+import ctypes
+import http.client
+import json
+import os
+from pathlib import Path
+import shutil
+import struct
+import subprocess
+import sys
+import threading
+import time
+import unittest
+from unittest import mock
+
+ROOT = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(ROOT / 'ui'))
+import frame_pc_agent as agent
+import frame_pc_capture as capture
+import frame_pcview
+import frame_macview
+from frame_stream_stats import Stats
+from test_macview import WS
+
+
+class GrantsTests(unittest.TestCase):
+    def test_source_bound_retry_ack_and_stop(self):
+        g = agent.Grants('master')
+        ticket = g.ticket('window:1')
+        self.assertIsNone(g.redeem('window:2', {'t': ticket}))
+        key = g.redeem('window:1', {'t': ticket})
+        self.assertEqual(key, g.redeem('window:1', {'t': ticket}))
+        g.ack(key)
+        self.assertIsNone(g.redeem('window:1', {'t': ticket}))
+        self.assertEqual(key, g.redeem('window:1', {'r': key}))
+        self.assertIsNone(g.redeem('window:2', {'r': key}))
+        g.revoke('window:1')
+        self.assertIsNone(g.redeem('window:1', {'r': key}))
+
+    def test_expiry_and_stop_before_redeem(self):
+        g = agent.Grants('master')
+        with mock.patch.object(agent.time, 'monotonic', return_value=1):
+            ticket = g.ticket('test')
+        with mock.patch.object(agent.time, 'monotonic', return_value=62):
+            self.assertIsNone(g.redeem('test', {'t': ticket}))
+        ticket = g.ticket('test')
+        g.revoke()
+        self.assertIsNone(g.redeem('test', {'t': ticket}))
+
+
+class GatingTests(unittest.TestCase):
+    """Experimental, Windows only, and off until the person turns it on."""
+
+    def view(self):
+        return frame_pcview.PCView(['ssh'], mock.Mock(), 'frame')
+
+    def test_only_windows_gets_the_pc_host(self):
+        for platform, cls in (('win32', frame_pcview.PCView), ('linux', frame_macview.MacView),
+                              ('darwin', frame_macview.MacView)):
+            with mock.patch.object(frame_pcview.sys, 'platform', platform):
+                view = frame_pcview.host_view(['ssh'], mock.Mock(), 'frame')
+            self.assertIs(type(view), cls, platform)
+
+    def test_off_by_default_starts_nothing(self):
+        view = self.view()
+        with mock.patch.object(frame_pcview.sys, 'platform', 'win32'), \
+                mock.patch.object(frame_macview.subprocess, 'Popen', side_effect=AssertionError('started while off')):
+            state = view.state()
+            self.assertEqual(state, {'available': False, 'reason': frame_pcview.OFF, 'host': view.host,
+                                     'experimental': True, 'enabled': False})
+            with self.assertRaises(frame_macview.MacViewError):
+                view.show('window:12')
+        view.run.assert_not_called()
+
+    def test_never_offered_off_windows_even_when_turned_on(self):
+        view = self.view()
+        view.enabled = True
+        with mock.patch.object(frame_pcview.sys, 'platform', 'linux'):
+            self.assertIn('only available on Windows', view.unavailable())
+
+    def test_turning_on_checks_for_the_bundled_libraries(self):
+        view = self.view()
+        missing = mock.Mock(is_file=mock.Mock(return_value=False))
+        with mock.patch.object(frame_pcview.sys, 'platform', 'win32'), \
+                mock.patch.object(frame_pcview, 'LIBRARY', missing):
+            state = view.set_enabled(True)
+        self.assertTrue(state['enabled'])
+        self.assertFalse(state['available'])
+        self.assertIn('libraries are missing', state['reason'])
+
+    def test_turning_off_stops_streams_and_the_helper(self):
+        view = self.view()
+        view.enabled = True
+        agent = mock.Mock()
+        agent.poll.return_value = None
+        view.agent, view.tunnel = agent, mock.Mock()
+        tunnel = view.tunnel
+        tunnel.poll.return_value = None
+        view.stop = mock.Mock()
+        with mock.patch.object(frame_pcview.sys, 'platform', 'win32'):
+            state = view.set_enabled(False)
+        view.stop.assert_called_once_with()
+        agent.stdin.close.assert_called_once()
+        agent.wait.assert_called()
+        tunnel.terminate.assert_called_once()
+        self.assertIsNone(view.agent)
+        self.assertEqual((state['enabled'], state['reason']), (False, frame_pcview.OFF))
+
+    def test_server_enable_action(self):
+        import sandbox  # noqa: F401  (keeps the server off real data and services)
+        import server
+        with mock.patch.object(server, 'macview', frame_macview.MacView(['ssh'], mock.Mock(), 'frame')):
+            with self.assertRaises(server.Failure) as e:
+                server.macview_action({'action': 'enable', 'on': True})
+            self.assertIn('only available on Windows', str(e.exception))
+        view = self.view()
+        view.set_enabled = mock.Mock(return_value={'enabled': True})
+        with mock.patch.object(server, 'macview', view):
+            self.assertEqual(server.macview_action({'action': 'enable', 'on': True}), {'enabled': True})
+            server.macview_action({'action': 'enable', 'on': 'yes'})  # anything but true is off
+        self.assertEqual([c.args for c in view.set_enabled.call_args_list], [(True,), (False,)])
+
+
+class PageTests(unittest.TestCase):
+    page = (ROOT / 'ui' / 'index.html').read_text(encoding='utf-8')
+
+    def test_tool_link_is_windows_only_and_marked_experimental(self):
+        self.assertIn('<a href="#macview" id="pcToolLink" hidden><span>PC in the headset</span>'
+                      '<small>Experimental:', self.page)
+        self.assertIn('$("pcToolLink").hidden = h.mobile || h.os !== "Windows";', self.page)
+        self.assertIn('$("macToolLink").hidden = h.mobile || h.os !== "macOS";', self.page)
+
+    def test_card_says_experimental_and_what_is_unverified(self):
+        self.assertIn('<span class="tag" id="mvTag" hidden>Experimental</span>', self.page)
+        self.assertIn('<input type="checkbox" id="mvPcOn">', self.page)
+        self.assertIn("hasn't been tried on a real\n          Windows desktop or with a headset yet", self.page)
+        self.assertIn('docs/pc-in-headset.md', self.page)
+
+    def test_opt_in_is_remembered_with_the_client_preferences(self):
+        self.assertIn("const keys = ['mvSeparate', 'padUsed', 'pcView']", self.page)
+        prefs = (ROOT / 'app' / 'preferences.js').read_text(encoding='utf-8')
+        self.assertIn('const KEYS = ["mvSeparate", "padUsed", "pcView"];', prefs)
+
+
+class AdapterTests(unittest.TestCase):
+    def test_windows_uses_wgc_and_media_foundation(self):
+        for kind in ('window', 'display'):
+            pipeline = capture.pipeline(dict(src=kind+':42'), 'win32', 'mfh264enc', 640, 360, 30, 1000000)
+            self.assertIn('capture-api=wgc', pipeline)
+            self.assertIn('window-handle=42' if kind == 'window' else 'monitor-handle=42', pipeline)
+            self.assertIn('mfh264enc name=enc low-latency=true bframes=0', pipeline)
+            self.assertNotIn('drop=true', pipeline)
+        with self.assertRaises(ValueError):
+            capture.pipeline(dict(src='window:42 ! fakesink'), 'win32', 'mfh264enc', 640, 360, 30, 1000000)
+
+    def test_linux_uses_only_portal_fd_and_node(self):
+        p = capture.pipeline(dict(src='window:consented', fd=19, node=47), 'linux', 'x264enc', 640, 360, 30, 1000000)
+        self.assertIn('pipewiresrc fd=19 path=47', p)
+        self.assertIn('tune=zerolatency', p)
+        self.assertEqual(capture.dimensions(1920, 1080, 1280), (1280, 720))
+
+    def test_portal_input_clamps_and_releases_held_state(self):
+        native = mock.Mock()
+        native.lib.fc_portal_input.return_value = 1
+        inp = capture.PortalInput(native, dict(portal=123, w=100, h=50))
+        inp.handle(dict(t='m', e='down', b=0, x=2, y=-1))
+        inp.handle(dict(t='k', e='down', key='Control'))
+        inp.release()
+        calls = native.lib.fc_portal_input.call_args_list
+        self.assertEqual(calls[0].args, (123, 0, 99, 0, 0, 0))
+        self.assertIn(mock.call(123, 1, 0, 0, 0x110, 0), calls)
+        self.assertIn(mock.call(123, 3, 0, 0, 0xffe3, 0), calls)
+        self.assertFalse(inp.buttons or inp.keys)
+
+    def test_windows_release_and_negative_monitor_origin(self):
+        host = mock.Mock()
+        host.user.GetSystemMetrics.side_effect = [-1920, 0, 3840, 1080]
+        inp = capture.WindowsInput(host, dict(src='display:4', x=-1920, y=0, w=1920, h=1080))
+        inp.handle(dict(t='m', e='down', b=2, x=0, y=0))
+        self.assertEqual(host.send.call_args_list[0], mock.call(mouse=(0, 0, 0, 0xc001)))
+        inp.handle(dict(t='k', e='down', code='ControlLeft', key='Control'))
+        inp.release()
+        self.assertIn(mock.call(mouse=(0, 0, 0, 0x10)), host.send.call_args_list)
+        self.assertIn(mock.call(key=(162, 0, 2)), host.send.call_args_list)
+
+    def test_refused_windows_focus_never_clicks_the_covering_app(self):
+        host = mock.Mock()
+        host.rect.return_value = (0, 0, 800, 600)
+        host.user.GetForegroundWindow.return_value = 99
+        host.user.SetForegroundWindow.return_value = False
+        inp = capture.WindowsInput(host, dict(src='window:12', w=800, h=600))
+        with self.assertRaisesRegex(RuntimeError, 'could not focus'):
+            inp.handle(dict(t='m', e='down', b=0, x=.5, y=.5))
+        host.send.assert_not_called()
+
+    def test_pc_reuses_launcher_and_namespaces_panel_ids(self):
+        view = frame_pcview.PCView(['ssh'], mock.Mock(return_value='panel created'), 'frame')
+        view.call = mock.Mock(side_effect=lambda path, **kw: {'screen': True, 'ticket': 'one-use', 'streams': []})
+        view.ensure_tunnel = mock.Mock()
+        view.remote_port = 47900
+        view.show('window:12')
+        self.assertEqual(view.run.call_args.kwargs['stdin'], frame_macview.LAUNCH)
+        self.assertNotEqual(frame_macview.panel_id('window:12'), frame_macview.panel_id('window:12', 'windows'))
+        self.assertFalse(view.prefer_usb)
+        with self.assertRaises(frame_macview.MacViewError):
+            view.show('separate:12')
+
+    def test_session_end_releases_native_input_only_once(self):
+        session = object.__new__(agent.Session)
+        session.lock, session.input_lock = threading.RLock(), threading.RLock()
+        session.stop_event = threading.Event()
+        session.ws, session.input = mock.Mock(), mock.Mock()
+        session.released = False
+        session.end()
+        session.end()
+        session.input.release.assert_called_once()
+        self.assertTrue(session.stop_event.is_set())
+
+    def test_idle_source_is_not_a_stall(self):
+        # PipeWire/WGC deliver frames only on damage: a static desktop sends
+        # its first frame and then nothing. That must not end the session.
+        session = object.__new__(agent.Session)
+        session.lock, session.pending = threading.RLock(), {}
+        session.stats = Stats(lambda: 0)
+        session.stats.captured = 1
+        self.assertIsNone(session.stalled(60000000, 0, 0))
+        # A frame that entered the encoder and never came out is a fault.
+        session.pending[5] = dict(cap=0, arr=0, e0=1000000, tier=0, br=0)
+        self.assertIn('encoder', session.stalled(12000000, 0, 0))
+        self.assertIsNone(session.stalled(10000000, 0, 0))
+        # No initial frame at all after the pipeline opened is a fault.
+        session.pending.clear()
+        self.assertIn('capture', session.stalled(12000000, 0, 1))
+        self.assertIsNone(session.stalled(9000000, 0, 1))
+
+    def test_controller_is_inert_after_close(self):
+        lib = mock.Mock()
+        lib.fc_new.return_value = 1234
+        lib.fc_value.return_value = 100
+        controller = capture.Controller(lib, 60, 5000000)
+        controller.close()
+        lib.fc_free.assert_called_once_with(1234)
+        lib.reset_mock()
+        state = controller.state()
+        self.assertEqual((state['fps'], state['target'], state['scale']), (60, 0, 1))
+        self.assertEqual(controller.call('gate', 1, 1), 0)
+        self.assertEqual(controller.update(1), 0)
+        controller.close()
+        self.assertEqual(lib.method_calls, [])  # nothing touched the freed pointer
+
+    def test_library_path_prepend_adds_no_empty_entry(self):
+        env = {}
+        frame_pcview.prepend(env, 'LD_LIBRARY_PATH', '/opt/fc/lib')
+        self.assertEqual(env['LD_LIBRARY_PATH'], '/opt/fc/lib')
+        frame_pcview.prepend(env, 'LD_LIBRARY_PATH', '/x')
+        self.assertEqual(env['LD_LIBRARY_PATH'], '/x' + os.pathsep + '/opt/fc/lib')
+        with mock.patch.dict(os.environ, clear=True):
+            env = frame_pcview.PCView([], lambda *a: None, 'frame').agent_environment()
+        for name in ('PATH', 'LD_LIBRARY_PATH'):
+            parts = env.get(name, 'x').split(os.pathsep)
+            self.assertNotIn('', parts, name)
+
+    def test_malformed_viewer_input_is_dropped_not_fatal(self):
+        session = object.__new__(agent.Session)
+        session.lock, session.input_lock = threading.RLock(), threading.RLock()
+        session.stop_event, session.key_event = threading.Event(), threading.Event()
+        session.src, session.codec, session.key, session.w, session.h = 'display:1', 'h264', 'r', 100, 100
+        session.source = dict(src='display:1', w=100, h=100, portal=1)
+        session.input_enabled, session.released = True, False
+        session.native = mock.Mock()
+        session.native.now.return_value = 0
+        session.controller, session.agent = mock.Mock(), mock.Mock()
+        session.stats = Stats(lambda: 0)
+        session.produce = lambda: None
+        lib = mock.Mock()
+        lib.fc_portal_input.return_value = 1
+        session.input = capture.PortalInput(mock.Mock(lib=lib), session.source)
+        session.ws = mock.Mock()
+        session.ws.receive.side_effect = [
+            dict(t='m', x='left', y=0), dict(t='wheel', dx=[1]), dict(t='k', e='down', key=None, i='x'),
+            dict(t='fd', drop='many'), dict(t='rx', s=[1]), dict(t='m', x=.5, y=.5), ConnectionError('closed')]
+        with self.assertRaises(ConnectionError):
+            session.start()
+        # Every malformed message was skipped; the good move after them still ran.
+        moves = [c.args for c in lib.fc_portal_input.call_args_list if c.args[1] == 0]
+        self.assertAlmostEqual(moves[-1][2], .5*99)
+        self.assertEqual(session.ws.receive.call_count, 7)
+
+    def test_stats_keep_capture_time_and_bound_records(self):
+        stats = Stats(lambda: 10000000)
+        stats.input(dict(t='m', i=1, tv=9999990))
+        f = stats.add(cap=10000001, arr=10000002, e0=10000003, e1=10000004)
+        self.assertEqual(f['echo'], 1)
+        stats.report(dict(t='rx', s=f['s'], r=10000010))
+        stats.report(dict(t='fd', f=[[f['s'], 10000011, 10000012, 10000013]]))
+        self.assertEqual(stats.snapshot(settle=0)['inputs'][0]['frame'], f['s'])
+        for _ in range(4100):
+            stats.add(cap=10000001)
+        self.assertEqual(len(stats.frames), 4096)
+
+
+def x264_bundled():
+    return any((capture.NATIVE / 'lib' / 'gstreamer-1.0').glob('*gstx264*'))
+
+
+def needs_x264(test):
+    def run(self):
+        if not x264_bundled():
+            if os.environ.get('FRAME_PC_REQUIRE_X264') == '1':
+                raise AssertionError('CI required x264 in the native PC bundle (desktop/build.py --with-x264)')
+            raise unittest.SkipTest('x264 is only in CI test bundles, not the installer')
+        return test(self)
+    run.__name__, run.__doc__ = test.__name__, test.__doc__
+    return run
+
+
+class NativeTests(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        if not capture.LIBRARY.exists():
+            if os.environ.get('FRAME_PC_REQUIRE_NATIVE') == '1':
+                raise AssertionError('CI required native PC libraries but they were not built')
+            raise unittest.SkipTest('native PC libraries not built on this host')
+        cls.token = 'test-' + os.urandom(8).hex()
+        env = frame_pcview.PCView([], lambda *a: None, 'frame').agent_environment()
+        env['FRAME_MAC_VIEW_TOKEN'] = cls.token
+        cls.proc = subprocess.Popen([sys.executable, str(ROOT/'ui/frame_pc_agent.py'), 'serve', '--port', '0',
+            '--page', str(ROOT/'ui/mac-view.html'), '--exit-on-eof'], stdin=subprocess.PIPE, stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE, text=True, env=env)
+        line = cls.proc.stdout.readline()
+        if 'listening' not in line:
+            raise AssertionError('Native agent failed: ' + cls.proc.stderr.read())
+        cls.port = int(line.rsplit(':', 1)[1])
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.proc.stdin.close()
+        try:
+            rc = cls.proc.wait(10)
+        except subprocess.TimeoutExpired:
+            cls.proc.kill()
+            raise AssertionError('Native agent did not stop after EOF')
+        error = cls.proc.stderr.read()
+        cls.proc.stdout.close()
+        cls.proc.stderr.close()
+        if rc:
+            raise AssertionError('Native agent exited %s: %s' % (rc, error))
+
+    def request(self, path, method='GET'):
+        conn = http.client.HTTPConnection('127.0.0.1', self.port, timeout=10)
+        try:
+            conn.request(method, path)
+            response = conn.getresponse()
+            return response.status, response.read()
+        finally:
+            conn.close()
+
+    def tearDown(self):
+        self.request('/close?k='+self.token, 'POST')
+
+    @unittest.skipUnless(sys.platform.startswith('linux'), 'Linux PipeWire client libraries')
+    def test_bundled_pipewire_context_needs_no_system_modules(self):
+        # No portal request, remote connection or desktop capture: create and
+        # destroy a private client context to test the dynamically loaded SPA
+        # and protocol modules that ldd cannot discover.
+        code = """
+import ctypes as C, os
+lib = C.CDLL(os.path.join(os.environ['FRAME_PC_NATIVE'], 'lib', 'libpipewire-0.3.so.0'))
+for name, ret, args in [
+    ('pw_init', None, [C.c_void_p, C.c_void_p]),
+    ('pw_main_loop_new', C.c_void_p, [C.c_void_p]),
+    ('pw_main_loop_get_loop', C.c_void_p, [C.c_void_p]),
+    ('pw_context_new', C.c_void_p, [C.c_void_p, C.c_void_p, C.c_size_t]),
+    ('pw_context_find_factory', C.c_void_p, [C.c_void_p, C.c_char_p]),
+    ('pw_context_find_spa_lib', C.c_char_p, [C.c_void_p, C.c_char_p]),
+    ('pw_context_destroy', None, [C.c_void_p]),
+    ('pw_main_loop_destroy', None, [C.c_void_p])]:
+    fn = getattr(lib, name)
+    fn.restype, fn.argtypes = ret, args
+lib.pw_init(None, None)
+loop = lib.pw_main_loop_new(None)
+assert loop, 'bundled SPA loop support did not load'
+context = lib.pw_context_new(lib.pw_main_loop_get_loop(loop), None, 0)
+assert context, 'bundled PipeWire client modules did not load'
+assert lib.pw_context_find_factory(context, b'adapter'), 'video adapter factory is missing'
+# The exported factory is video.adapt, which needs a live follower node to
+# instantiate. Check its configured library and exported factory without
+# pretending a headless context is a consented video stream.
+plugin_name = lib.pw_context_find_spa_lib(context, b'video.adapt')
+assert plugin_name, 'video.adapt has no bundled library mapping'
+plugin = C.CDLL(os.path.join(os.environ['SPA_PLUGIN_DIR'], plugin_name.decode() + '.so'))
+class Factory(C.Structure):
+    _fields_ = [('version', C.c_uint32), ('name', C.c_char_p)]
+plugin.spa_handle_factory_enum.argtypes = [C.POINTER(C.POINTER(Factory)), C.POINTER(C.c_uint32)]
+plugin.spa_handle_factory_enum.restype = C.c_int
+factory, index, names = C.POINTER(Factory)(), C.c_uint32(), []
+while plugin.spa_handle_factory_enum(C.byref(factory), C.byref(index)) > 0:
+    names.append(factory.contents.name)
+assert b'video.adapt' in names, 'bundled SPA video adapter factory is missing'
+lib.pw_context_destroy(context)
+lib.pw_main_loop_destroy(loop)
+"""
+        env = frame_pcview.PCView([], lambda *a: None, 'frame').agent_environment()
+        env['FRAME_PC_NATIVE'] = str(capture.NATIVE)
+        result = subprocess.run([sys.executable, '-c', code], env=env, capture_output=True, text=True, timeout=15)
+        self.assertEqual(result.returncode, 0, result.stderr)
+
+    def test_agent_reports_its_host_and_encoder(self):
+        self.assertEqual(self.request('/status')[0], 403)
+        status, body = self.request('/status?k='+self.token)
+        self.assertEqual(status, 200)
+        data = json.loads(body)
+        if sys.platform == 'win32':
+            self.assertEqual((data['host'], data['encoder']), ('windows', 'mfh264enc'))
+        self.assertEqual(data['streams'], [])
+
+    @unittest.skipUnless(os.environ.get('FRAME_PC_INSTALLER_BUNDLE') == '1', 'checks the installer\'s bundle')
+    def test_installer_bundle_leaves_out_gpl_x264(self):
+        self.assertFalse(x264_bundled())
+        self.assertFalse(list((capture.NATIVE / 'bin').glob('libx264*')))
+        plugins = [p.name for p in (capture.NATIVE / 'lib' / 'gstreamer-1.0').iterdir()]
+        for name in ('mediafoundation', 'd3d11', 'jpeg'):
+            self.assertTrue(any(p.endswith('gst%s.dll' % name) for p in plugins), (name, plugins))
+
+    @needs_x264
+    def test_last_raw_picture_survives_a_closed_gate(self):
+        # A source sends ONE changed frame, then becomes idle. It must reach
+        # the encoder after congestion clears, without needing another update.
+        code = """
+import ctypes as C, sys, time
+from frame_pc_capture import Native, GATE, Encoded, pipeline
+native = Native()
+start = None
+closing = False
+phases = []
+def gate(stage, pts, capture, arrived):
+    global start
+    phases.append(stage)
+    if closing: return -1
+    if start is None: start = time.monotonic()
+    return int(stage == 1 or time.monotonic()-start >= .15)
+callback = GATE(gate)
+p = pipeline(dict(src='test'), sys.platform, 'x264enc', 320, 180, 30, 300000)
+p = p.replace('is-live=true', 'is-live=true num-buffers=1')
+error = C.create_string_buffer(1024)
+handle = native.lib.fc_capture_open(p.encode(), callback, error, len(error))
+assert handle, error.value
+try:
+    frame = Encoded()
+    result = 0
+    deadline = time.monotonic()+5
+    while not result and time.monotonic() < deadline:
+        result = native.lib.fc_capture_pull(handle, C.byref(frame))
+    assert result == 1, native.lib.fc_capture_error(handle)
+    assert frame.key and frame.size > 17
+    assert phases.count(0) == 1 and 2 in phases, phases
+finally:
+    closing = True
+    native.lib.fc_capture_close(handle)
+"""
+        env = frame_pcview.PCView([], lambda *a: None, 'frame').agent_environment()
+        env['PYTHONPATH'] = str(ROOT / 'ui')
+        result = subprocess.run([sys.executable, '-c', code], env=env, capture_output=True, text=True, timeout=10)
+        self.assertEqual(result.returncode, 0, result.stderr)
+
+    @needs_x264
+    def test_auth_and_real_h264_stats(self):
+        self.assertEqual(self.request('/status')[0], 403)
+        status, body = self.request('/ticket?src=test&k='+self.token, 'POST')
+        self.assertEqual(status, 200)
+        ticket = json.loads(body)['ticket']
+        ws = WS(self.port, '/stream?src=test&fps=30&max=640&t='+ticket)
+        try:
+            self.assertEqual(ws.status, 101)
+            key, got, echo = None, 0, False
+            ws.send_text(json.dumps(dict(t='m', e='down', i=7, tv=1, x=.2, y=.3)))
+            deadline = time.monotonic()+10
+            while time.monotonic() < deadline and (got < 5 or not echo):
+                op, data = ws.recv()
+                if op == 1:
+                    m = json.loads(data)
+                    self.assertNotEqual(m.get('t'), 'error', m)
+                    if m.get('t') == 'hello':
+                        key = m['r']
+                        ws.send_text(json.dumps(dict(t='ack')))
+                elif op == 2:
+                    got += 1
+                    seq, echoed = struct.unpack('!II', data[9:17])
+                    now = struct.unpack('!Q', data[1:9])[0]
+                    echo |= echoed == 7
+                    self.assertIn(b'\x00\x00\x00\x01', data[17:])
+                    ws.send_text(json.dumps(dict(t='rx', s=seq, r=now+100)))
+                    ws.send_text(json.dumps(dict(t='fd', f=[[seq, now+200, now+300, now+400]])))
+            self.assertGreaterEqual(got, 5)
+            self.assertTrue(echo)
+            time.sleep(.1)
+            stats = json.loads(self.request('/stats?settle=0&k='+self.token)[1])['streams'][0]
+            self.assertGreater(stats['frames'][0]['e1'], stats['frames'][0]['e0'])
+            self.assertIn('controller', stats)
+            used = WS(self.port, '/stream?src=test&t='+ticket)
+            self.assertEqual(used.status, 403)
+            used.close()
+            self.request('/close?src=test&k='+self.token, 'POST')
+            revoked = WS(self.port, '/stream?src=test&r='+key)
+            self.assertEqual(revoked.status, 403)
+            revoked.close()
+        finally:
+            ws.close()
+
+
+if __name__ == '__main__':
+    unittest.main()

ui/frame_backup.py

@@ -0,0 +1,402 @@
+"""Backup and recovery kit: copy game saves, settings and Android app data off the Frame,
+put them back after a factory reset, and get out of Desktop Mode. Python stdlib only.
+
+A backup is a folder in ~/Documents/Frame Control Backups/<YYYY-MM-DD-HHMMSS>/ on this
+computer: one tar.gz per part (saves/, settings/, android/) and manifest.json listing every
+file with its size and SHA-256, the archives' checksums and the headset's BUILD_ID. What the
+parts hold, and what is never copied, is decided on the headset by frame_backup_remote.py.
+Backing up only reads the headset. See docs/backup-and-recovery.md.
+
+CLI: python3 ui/frame_backup.py backup | list | plan NAME | restore NAME PART... | session | game-mode
+"""
+import hashlib
+import json
+import os
+from pathlib import Path
+import re
+import shlex
+import shutil
+import subprocess
+import sys
+import tarfile
+import time
+
+import frame_android as android
+import frame_host
+
+REMOTE = Path(__file__).resolve().parent / 'frame_backup_remote.py'
+NAME = re.compile(r'^\d{4}-\d{2}-\d{2}-\d{6}$')
+ARCHIVE = re.compile(r'^(saves|settings|android)/[A-Za-z0-9._-]{1,200}\.tar\.gz$')
+PART = re.compile(r'^(saves:(\d{1,10}|linux)|settings:(steam|system)|android:[A-Za-z][\w]*(\.[A-Za-z_][\w]*)+)$')
+KINDS = ('saves', 'settings', 'android')
+FORMAT = 1
+# The switch Valve's own devkit tools use (frame/devkit-utils/steamos-delete). Nothing else
+# is ever run as a session command.
+SELECTORS = ('holo-session-select', 'steamos-session-select')
+REASONS = {
+    'not_installed': 'Install the game first, then restore its saves',
+    'no_prefix': 'Start the game once so Proton sets up its folders, then restore',
+    'no_account': 'Sign in to Steam on the headset first',
+    'reference': 'Kept for reference only; copy by hand if you need it',
+    'refused': 'Not restored: the path is not safe to write',
+    'running': 'Close the app first',
+    'damaged': "The backup file doesn't match its checksum",
+    'missing': 'The backup file is missing',
+    'empty': 'Nothing to restore',
+    'unknown': 'Not something this version of Frame Control can restore',
+}
+
+
+class BackupError(android.FrameError):
+    pass
+
+
+def backup_root():
+    return Path(os.environ.get('FRAME_BACKUP_DIR') or Path.home() / 'Documents' / 'Frame Control Backups')
+
+
+def backup_path(name):
+    """The folder for a backup name; refuses anything that isn't one of ours."""
+    if not isinstance(name, str) or not NAME.fullmatch(name):
+        raise BackupError('not a backup name')
+    root = backup_root().resolve()
+    path = (root / name).resolve()
+    if path.parent != root:
+        raise BackupError('not a backup name')
+    return path
+
+
+def archive_name(part):
+    kind, _, rest = part.partition(':')
+    return '%s/%s.tar.gz' % (kind, rest if kind == 'android' else part.replace(':', '-'))
+
+
+def remote_command(cmd, *args):
+    return shlex.join(['python3', '-c', REMOTE.read_text(), cmd, *args])
+
+
+def _ssh(command, src=None, dst=None, timeout=1800):
+    try:
+        # src: bytes, or a file to stream (an archive can be larger than memory).
+        feed = {'input': src} if isinstance(src, bytes) else {
+            'stdin': src if src is not None else subprocess.DEVNULL}
+        result = frame_host.run_ssh(['ssh', *android.SSH_OPTS, android.FRAME, command], **feed,
+                                    stdout=dst if dst is not None else subprocess.PIPE,
+                                    stderr=subprocess.PIPE, timeout=timeout)
+    except subprocess.TimeoutExpired:
+        raise BackupError('the headset took too long to answer')
+    except OSError as error:
+        raise BackupError('could not reach the headset: ' + str(error))
+    if result.returncode:
+        raise BackupError(result.stderr.decode(errors='replace').strip()[-600:] or
+                          'the headset command failed')
+    return result.stdout
+
+
+def remote_json(cmd, *args, src=None, timeout=120):
+    out = _ssh(remote_command(cmd, *args), src=src, timeout=timeout)
+    try:
+        return json.loads(out)
+    except (ValueError, TypeError):
+        raise BackupError('unexpected answer from the headset')
+
+
+def _sha256(path):
+    digest = hashlib.sha256()
+    with open(str(path), 'rb') as src:
+        for chunk in iter(lambda: src.read(1024 * 1024), b''):
+            digest.update(chunk)
+    return digest.hexdigest()
+
+
+def inspect_archive(path):
+    """Every file in one of our part archives, with its size and SHA-256; refuses anything else."""
+    files, names = [], set()
+    try:
+        with tarfile.open(str(path), 'r:gz') as archive:
+            for member in archive:
+                name = member.name
+                parts = name.split('/')
+                if (not member.isfile() or name.startswith('/') or '\\' in name or name in names
+                        or any(p in ('', '.', '..') for p in parts)):
+                    raise BackupError('backup archive has an unsafe entry: %r' % name[:200])
+                names.add(name)
+                digest = hashlib.sha256()
+                src = archive.extractfile(member)
+                for chunk in iter(lambda: src.read(1024 * 1024), b''):
+                    digest.update(chunk)
+                files.append({'path': name, 'bytes': member.size, 'sha256': digest.hexdigest()})
+    except (OSError, EOFError, tarfile.TarError) as error:
+        raise BackupError('could not read the backup archive: ' + str(error))
+    return files
+
+
+def preview():
+    """What a backup would hold, before making one."""
+    plan = remote_json('plan')
+    apps, error = _android_apps()
+    return {'build': plan.get('build'), 'version': plan.get('version'), 'parts': plan.get('parts', []),
+            'android': apps, 'android_error': error, 'excluded': plan.get('excluded', []), 'folder': str(backup_root())}
+
+
+def _android_apps():
+    """(installed Android apps, None) or ([], why they couldn't be listed)."""
+    try:
+        return [{'package': a['package'], 'label': a.get('label') or a['package'],
+                 'running': bool(a.get('running'))} for a in android.list_apps()], None
+    except android.FrameError as error:
+        return [], str(error)
+
+
+def backup(report=lambda stage, percent=None: None, kinds=KINDS, headset=None):
+    kinds = [k for k in KINDS if k in kinds]
+    if not kinds:
+        raise BackupError('choose something to back up')
+    report('Reading what is on the headset', 1)
+    plan = remote_json('plan')
+    parts = [p for p in plan.get('parts', []) if p.get('kind') in kinds and PART.fullmatch(str(p.get('id')))]
+    apps, error = _android_apps() if 'android' in kinds else ([], None)
+    root = backup_root()
+    root.mkdir(parents=True, exist_ok=True)
+    name = time.strftime('%Y-%m-%d-%H%M%S')
+    final = backup_path(name)
+    if final.exists():
+        raise BackupError('a backup was started this second already; try again')
+    # Built under a hidden name and renamed when complete, so a cut-off backup is never listed.
+    staging = root / ('.' + name + '.partial')
+    staging.mkdir()
+    entries = []
+    skipped = [{'id': 'android', 'label': 'Android apps', 'reason': error}] if error else []
+    total = len(parts) + len(apps) or 1
+    try:
+        for i, part in enumerate(parts):
+            report('Copying ' + part['label'], 2 + 90 * i / total)
+            rel = archive_name(part['id'])
+            dest = staging / rel
+            dest.parent.mkdir(parents=True, exist_ok=True)
+            with open(str(dest), 'wb') as dst:
+                _ssh(remote_command('pack', part['id']), dst=dst)
+            files = inspect_archive(dest)
+            entries.append({'id': part['id'], 'kind': part['kind'], 'label': part['label'],
+                            'appid': part.get('appid'), 'archive': rel, 'sha256': _sha256(dest),
+                            'archive_bytes': dest.stat().st_size, 'files': files,
+                            'bytes': sum(f['bytes'] for f in files)})
+            skipped += [{'id': part['id'], 'label': part['label'], 'path': s['path'], 'reason': s['reason']}
+                        for s in part.get('skipped', [])]
+        for j, app in enumerate(apps):
+            report('Copying ' + app['label'] + ' (Android app data)', 2 + 90 * (len(parts) + j) / total)
+            part_id = 'android:' + app['package']
+            if app['running']:
+                skipped.append({'id': part_id, 'label': app['label'], 'reason': 'It was open; close it and back up again'})
+                continue
+            rel = archive_name(part_id)
+            dest = staging / rel
+            dest.parent.mkdir(parents=True, exist_ok=True)
+            try:
+                result = android.backup_data(app['package'], dest)
+            except android.FrameError as error:
+                skipped.append({'id': part_id, 'label': app['label'], 'reason': str(error)})
+                continue
+            entries.append({'id': part_id, 'kind': 'android', 'label': app['label'] + ' (Android app data)',
+                            'package': app['package'], 'instance': result.get('instance'), 'archive': rel,
+                            'sha256': result['sha256'], 'archive_bytes': dest.stat().st_size,
+                            'files': result.get('files'), 'bytes': result.get('bytes')})
+        report('Writing the manifest', 95)
+        manifest = {'format': FORMAT, 'app': 'Frame Control', 'name': name,
+                    'created': time.strftime('%Y-%m-%dT%H:%M:%S%z'),
+                    'headset': {'name': headset or android.FRAME, 'build': plan.get('build'),
+                                'version': plan.get('version')},
+                    'parts': entries, 'skipped': skipped, 'excluded': plan.get('excluded', [])}
+        (staging / 'manifest.json').write_text(json.dumps(manifest, indent=1))
+        os.rename(str(staging), str(final))
+    except BaseException:
+        shutil.rmtree(str(staging), ignore_errors=True)
+        raise
+    size = sum(e['archive_bytes'] for e in entries)
+    message = 'Backed up %d part%s (%s) to %s' % (len(entries), '' if len(entries) == 1 else 's',
+                                                   human(size), final)
+    if skipped:
+        message += '; %d skipped' % len(skipped)
+    return {'message': message, 'name': name, 'path': str(final), 'parts': len(entries),
+            'bytes': size, 'skipped': skipped}
+
+
+def human(n):
+    for unit in ('bytes', 'KB', 'MB', 'GB'):
+        if n < 1000 or unit == 'GB':
+            return ('%d %s' % (n, unit)) if unit == 'bytes' else '%.1f %s' % (n, unit)
+        n /= 1000.0
+
+
+def read_manifest(name):
+    path = backup_path(name)
+    try:
+        manifest = json.loads((path / 'manifest.json').read_text())
+    except (OSError, ValueError):
+        raise BackupError('that backup has no readable manifest')
+    if not isinstance(manifest, dict) or manifest.get('format') != FORMAT or \
+            not isinstance(manifest.get('parts'), list):
+        raise BackupError('that backup was made by a newer or unknown version')
+    for part in manifest['parts']:
+        if (not isinstance(part, dict) or not PART.fullmatch(str(part.get('id'))) or
+                not ARCHIVE.fullmatch(str(part.get('archive'))) or part['archive'] != archive_name(part['id'])):
+            raise BackupError('that backup manifest lists something unexpected')
+    return path, manifest
+
+
+def list_backups():
+    root = backup_root()
+    out = []
+    try:
+        names = sorted((p.name for p in root.iterdir() if NAME.fullmatch(p.name) and p.is_dir()), reverse=True)
+    except OSError:
+        names = []
+    for name in names:
+        try:
+            _, m = read_manifest(name)
+        except BackupError as error:
+            out.append({'name': name, 'error': str(error)})
+            continue
+        out.append({'name': name, 'created': m.get('created'), 'build': (m.get('headset') or {}).get('build'),
+                    'headset': (m.get('headset') or {}).get('name'), 'parts': len(m['parts']),
+                    'bytes': sum(p.get('archive_bytes') or 0 for p in m['parts'])})
+    return {'backups': out, 'folder': str(root)}
+
+
+def restore_plan(name):
+    """Each part of a backup and whether it can go back now; reads only."""
+    path, manifest = read_manifest(name)
+    plans, check = {}, []
+    for part in manifest['parts']:
+        archive = path / part['archive']
+        state = None
+        if not archive.is_file():
+            state = 'missing'
+        elif _sha256(archive) != part.get('sha256'):
+            state = 'damaged'
+        plans[part['id']] = {'id': part['id'], 'kind': part.get('kind'), 'label': part.get('label'),
+                             'bytes': part.get('bytes'), 'status': state}
+        if state is None and part['kind'] != 'android':
+            check.append({'id': part['id'], 'files': [f['path'] for f in part.get('files') or []]})
+    if check:
+        answer = remote_json('check', src=json.dumps({'parts': check}).encode())
+        for result in answer.get('parts', []):
+            plan = plans.get(result.get('id'))
+            if plan:
+                plan.update(status=result.get('status'), replace=result.get('replace', 0),
+                            new=result.get('new', 0), held=result.get('held', {}))
+    android_parts = [p for p in plans.values() if p['kind'] == 'android' and p['status'] is None]
+    if android_parts:
+        installed = {a['package']: a for a in android.list_apps()}
+        for plan in android_parts:
+            app = installed.get(plan['id'].split(':', 1)[1])
+            plan['status'] = 'not_installed' if not app else 'running' if app.get('running') else 'ok'
+            if plan['status'] == 'not_installed':
+                plan['reason'] = 'Install the app first, then restore its data'
+            elif plan['status'] == 'ok':
+                plan['replace'] = 1  # the app's whole private data folder, kept beside it
+    for plan in plans.values():
+        plan.setdefault('reason', REASONS.get(plan['status']) if plan['status'] != 'ok' else None)
+    return {'name': name, 'headset': manifest.get('headset'), 'parts': list(plans.values())}
+
+
+def restore(name, ids, confirmed=False, report=lambda stage, percent=None: None):
+    """Restore the chosen parts that can go back now; the rest are skipped, not failed."""
+    if not isinstance(ids, list) or not ids or not all(isinstance(i, str) and PART.fullmatch(i) for i in ids):
+        raise BackupError('choose what to restore')
+    if confirmed is not True:
+        raise BackupError('confirm the restore first: it replaces files on the headset')
+    path, manifest = read_manifest(name)
+    by_id = {p['id']: p for p in manifest['parts']}
+    plan = {p['id']: p for p in restore_plan(name)['parts']}
+    stamp = time.strftime('%Y%m%d-%H%M%S')
+    done, skipped = [], []
+    for i, part_id in enumerate(ids):
+        part, state = by_id.get(part_id), plan.get(part_id)
+        if not part or not state:
+            skipped.append({'id': part_id, 'reason': 'Not in this backup'})
+            continue
+        if state['status'] != 'ok':
+            skipped.append({'id': part_id, 'label': state['label'], 'reason': state.get('reason') or state['status']})
+            continue
+        report('Restoring ' + state['label'], 5 + 90 * i / len(ids))
+        archive = path / part['archive']
+        try:
+            if part['kind'] == 'android':
+                result = android.restore_data(part_id.split(':', 1)[1], str(archive))
+            else:
+                with open(str(archive), 'rb') as src:
+                    result = remote_json('restore', part_id, stamp, src=src, timeout=1800)
+        except android.FrameError as error:
+            skipped.append({'id': part_id, 'label': state['label'], 'reason': str(error)})
+            continue
+        done.append(dict(result, id=part_id, label=state['label']))
+    message = 'Restored %d part%s' % (len(done), '' if len(done) == 1 else 's')
+    if skipped:
+        message += ', skipped %d' % len(skipped)
+    return {'message': message, 'restored': done, 'skipped': skipped}
+
+
+# ---- Game Mode ---------------------------------------------------------------
+
+def session_status():
+    return remote_json('session', timeout=30)
+
+
+def session_command(selector):
+    """The switch to Game Mode, exactly as Valve's devkit tools run it."""
+    if selector not in SELECTORS:
+        raise BackupError('this SteamOS build has no session switch command; use the steps in the guide')
+    return shlex.join([selector, 'gamescope'])
+
+
+def return_to_game_mode(confirmed=False):
+    if confirmed is not True:
+        raise BackupError('confirm first: switching closes the desktop and any apps open in it')
+    state = session_status()
+    if state.get('mode') == 'game':
+        return {'message': 'The headset is already in Game Mode. The desktop you see is a panel: '
+                           'close it from the Steam dashboard.', 'state': state, 'switched': False}
+    if state.get('mode') != 'desktop':
+        # Only a desktop session seen running is switched: the switch restarts the session,
+        # which would close whatever is running in Game Mode.
+        raise BackupError("couldn't tell that the headset is in Desktop Mode, so nothing was changed. "
+                          'Use the manual steps in the guide if it is stuck.')
+    command = session_command(state.get('selector'))
+    try:
+        # The session restarts under it, so the command may not get to answer.
+        _ssh(command, timeout=60)
+    except BackupError as error:
+        if 'took too long' not in str(error):
+            raise BackupError('the switch was refused: %s. Use the manual steps in the guide.' % error)
+    return {'message': 'Asked the headset to return to Game Mode; it restarts its session in a few seconds',
+            'state': state, 'switched': True, 'command': command}
+
+
+def main():
+    cmd, *args = sys.argv[1:] or ['help']
+    try:
+        if cmd == 'backup':
+            r = backup(lambda stage, percent=None: print(stage, file=sys.stderr))
+        elif cmd == 'list':
+            r = list_backups()
+        elif cmd == 'plan' and len(args) == 1:
+            r = restore_plan(args[0])
+        elif cmd == 'restore' and len(args) >= 2:
+            r = restore(args[0], args[1:], confirmed=True)
+        elif cmd == 'session':
+            r = session_status()
+        elif cmd == 'game-mode':
+            r = return_to_game_mode(confirmed=True)
+        else:
+            print(__doc__.strip().splitlines()[-1], file=sys.stderr)
+            return 2
+    except android.FrameError as error:
+        print('error:', error, file=sys.stderr)
+        return 1
+    print(json.dumps(r, indent=1))
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main())

ui/frame_backup_remote.py

@@ -0,0 +1,442 @@
+"""Backup and restore on the Frame: what to save, packing it and putting it back. Stdlib only.
+
+Runs on the headset as `python3 -c <this file> <command> ...` (ui/frame_backup.py sends it),
+so stdin is free for the archive or file list. Commands:
+
+  plan                 JSON: the headset's build and every part worth saving, with sizes
+  pack PART            a tar.gz of that part's files on stdout (reads only)
+  check                stdin JSON {"parts": [{"id", "files": [paths]}]}: what a restore would do
+  restore PART STAMP   stdin tar.gz: write that part's restorable files, keeping replaced ones
+  session              JSON: Game Mode or Desktop Mode, and the switch command on this image
+
+Paths are relative to the home folder, with '/' separators, everywhere: in archives, in the
+manifest and in `check`. Nothing here deletes a file. `restore` replaces only files named in
+its archive, and first copies each one it replaces under PREVIOUS/<stamp>/.
+"""
+import hashlib
+import json
+import os
+from pathlib import Path, PurePosixPath
+import re
+import shutil
+import subprocess
+import sys
+import tarfile
+import tempfile
+
+# FRAME_BACKUP_HOME: the tests point this at a folder laid out like the Frame's home.
+HOME = Path(os.environ.get('FRAME_BACKUP_HOME') or Path.home())
+STEAM = '.local/share/Steam'
+COMPAT = STEAM + '/steamapps/compatdata'
+PREFIX_USER = 'pfx/drive_c/users/steamuser'
+# Where Windows games keep saves inside a Proton prefix. Steam Cloud covers many games, not all.
+SAVE_DIRS = ('AppData/Roaming', 'AppData/Local', 'AppData/LocalLow', 'Documents', 'Saved Games')
+# Wine's and Windows' own folders inside those: caches, not saves.
+SAVE_SKIP = ('AppData/Local/Temp', 'AppData/Local/Microsoft', 'AppData/Roaming/Microsoft',
+             'AppData/Local/D3DSCache', 'AppData/Local/NVIDIA', 'AppData/Local/CrashDumps',
+             'AppData/LocalLow/Microsoft')
+# Native Linux games: the engines' standard save folders.
+LINUX_SAVES = ('.config/unity3d', '.local/share/godot/app_userdata')
+# Steam settings. Controller layouts go back; the rest is kept so you can look things up.
+STEAM_RESTORE = ('241100/remote/controller_config',)  # under userdata/<account>/
+STEAM_REFERENCE = ('config/localconfig.vdf', 'config/shortcuts.vdf', 'config/grid')
+STEAM_CONTROLLER = STEAM + '/steamapps/common/Steam Controller Configs'  # <account>/config/
+# Desktop settings worth keeping. Steam rewrites steamvr.vrsettings while SteamVR runs, so
+# it's only for reference.
+SYSTEM_RESTORE = ('.config/kdeglobals', '.config/kwinrc', '.config/kxkbrc', '.config/konsolerc',
+                  '.config/dolphinrc')
+SYSTEM_REFERENCE = ('.config/openvr/config/steamvr.vrsettings',)
+PREVIOUS = '.local/share/frame-control/restore-previous'
+MAX_FILE = 2 * 1024 ** 3      # a bigger "save" is a cache or a video; listed as skipped
+MAX_PART = 20 * 1024 ** 3
+MAX_FILES = 100000
+SHORTCUT_IDS = 2 ** 31        # non-Steam shortcuts and Lepton instances use ids above this
+
+# Never copied, whatever folder they turn up in. Checked on every path, packing and restoring.
+SECRET_NAMES = {'steam.token', 'loginusers.vdf', 'registry.vdf', 'config.vdf', 'secrets.env',
+                'authorized_keys', 'known_hosts', 'credentials', 'credentials.json'}
+SECRET_DIRS = {'.ssh', '.gnupg', '.pki', 'keyrings', 'kwalletd', 'cliproxyapi', 'tailscale'}
+SECRET_SUFFIXES = ('.token', '.pem', '.key', '.kwl')
+EXCLUDED = [
+    'Steam sign-in: steam.token, config/config.vdf, loginusers.vdf, registry.vdf, ssfn files',
+    'Keys and passwords: ~/.ssh, ~/.gnupg, keyrings and KWallet, *.token/*.key/*.pem files, '
+    'Tailscale and proxy settings (secrets.env)',
+    'Games themselves, Proton and runtimes (reinstall them from Steam), shader caches, Steam '
+    'Cloud folders under userdata/<account>/<appid>, screenshots (Tools → Capture & Live saves them)',
+    'Android apps themselves and their shared storage (/sdcard); only private app data is saved',
+    'Symbolic links, and single files over 2 GiB',
+]
+
+
+def is_secret(rel):
+    parts = PurePosixPath(rel).parts
+    name = parts[-1].lower() if parts else ''
+    return (name in SECRET_NAMES or name.startswith('ssfn') or name.startswith('id_rsa') or
+            name.startswith('id_ed25519') or name.startswith('id_ecdsa') or
+            name.endswith(SECRET_SUFFIXES) or any(p.lower() in SECRET_DIRS for p in parts[:-1]))
+
+
+def safe_rel(rel):
+    """A relative '/' path with no '..', '.', empty or absolute parts."""
+    if not isinstance(rel, str) or not rel or '\\' in rel or '\0' in rel or rel.startswith('/'):
+        return False
+    parts = rel.split('/')
+    return all(p not in ('', '.', '..') for p in parts) and not re.match(r'^[A-Za-z]:', rel)
+
+
+def _under(rel, root):
+    return rel == root or rel.startswith(root + '/')
+
+
+def _walk(rel_root, skip=()):
+    """Regular files under HOME/rel_root, never following links: [(rel, size)], [skipped]."""
+    files, skipped = [], []
+    base = HOME / rel_root
+    if base.is_symlink() or not base.is_dir():
+        if base.is_file() and not base.is_symlink():
+            return [(rel_root, base.stat().st_size)], skipped
+        return files, skipped
+    for top, dirs, names in os.walk(str(base)):
+        rel_top = PurePosixPath(rel_root, *Path(top).relative_to(base).parts).as_posix()
+        dirs[:] = sorted(d for d in dirs if not os.path.islink(os.path.join(top, d)) and
+                         not any(_under(rel_top + '/' + d, s) for s in skip) and
+                         not is_secret(rel_top + '/' + d + '/x'))
+        for name in sorted(names):
+            path, rel = os.path.join(top, name), rel_top + '/' + name
+            if os.path.islink(path) or is_secret(rel):
+                continue
+            try:
+                st = os.lstat(path)
+            except OSError:
+                continue
+            if not os.path.isfile(path):
+                continue
+            if st.st_size > MAX_FILE:
+                skipped.append({'path': rel, 'reason': 'over 2 GiB'})
+                continue
+            files.append((rel, st.st_size))
+    return files, skipped
+
+
+def _manifest_field(text, key):
+    m = re.search(r'"%s"\s+"([^"]*)"' % key, text)
+    return m.group(1) if m else None
+
+
+def game_name(appid):
+    try:
+        text = (HOME / STEAM / 'steamapps' / ('appmanifest_%s.acf' % appid)).read_text(errors='replace')
+    except OSError:
+        return None
+    return _manifest_field(text, 'name')
+
+
+def accounts():
+    root = HOME / STEAM / 'userdata'
+    try:
+        return sorted(p.name for p in root.iterdir() if p.name.isdigit() and p.is_dir()
+                      and not p.is_symlink() and p.name != '0')
+    except OSError:
+        return []
+
+
+def _prefixes():
+    try:
+        return sorted((p.name for p in (HOME / COMPAT).iterdir()
+                       if p.name.isdigit() and (p / PREFIX_USER).is_dir()), key=int)
+    except OSError:
+        return []
+
+
+def part_roots(part):
+    """(roots to save, roots that a restore may write) for a part id, or None if unknown."""
+    if part.startswith('saves:') and part[6:].isdigit():
+        user = '%s/%s/%s' % (COMPAT, part[6:], PREFIX_USER)
+        roots = tuple(user + '/' + d for d in SAVE_DIRS)
+        return roots, roots
+    if part == 'saves:linux':
+        return LINUX_SAVES, LINUX_SAVES
+    if part == 'settings:steam':
+        save, restore = [], []
+        for acct in accounts():
+            base = '%s/userdata/%s/' % (STEAM, acct)
+            restore += [base + r for r in STEAM_RESTORE] + ['%s/%s/config' % (STEAM_CONTROLLER, acct)]
+            save += [base + r for r in STEAM_REFERENCE]
+        return tuple(save + restore), tuple(restore)
+    if part == 'settings:system':
+        return SYSTEM_RESTORE + SYSTEM_REFERENCE, SYSTEM_RESTORE
+    return None
+
+
+def restore_roots(part, rel):
+    """The restore roots for rel within part; the Steam ones don't depend on today's accounts."""
+    if part == 'settings:steam':
+        m = re.match(r'^(?:%s/userdata/(\d+)/|%s/(\d+)/)' % (re.escape(STEAM), re.escape(STEAM_CONTROLLER)), rel)
+        acct = m and (m.group(1) or m.group(2))
+        if not acct:
+            return ()
+        base = '%s/userdata/%s/' % (STEAM, acct)
+        return tuple(base + r for r in STEAM_RESTORE) + ('%s/%s/config' % (STEAM_CONTROLLER, acct),)
+    roots = part_roots(part)
+    return roots[1] if roots else ()
+
+
+def part_files(part):
+    roots = part_roots(part)
+    if roots is None:
+        raise ValueError('unknown backup part %r' % part)
+    skip = ()
+    if part.startswith('saves:') and part != 'saves:linux':
+        skip = tuple('%s/%s/%s/%s' % (COMPAT, part[6:], PREFIX_USER, s) for s in SAVE_SKIP)
+    files, skipped = [], []
+    for root in roots[0]:
+        f, s = _walk(root, skip)
+        files += f
+        skipped += s
+    return files, skipped
+
+
+def part_label(part):
+    if part == 'saves:linux':
+        return 'Linux game saves (Unity and Godot games)'
+    if part == 'settings:steam':
+        return 'Steam settings and controller layouts'
+    if part == 'settings:system':
+        return 'Desktop and SteamVR settings'
+    appid = part[6:]
+    name = game_name(appid)
+    if name:
+        return name + ' saves'
+    return ('Non-Steam game %s saves' if int(appid) >= SHORTCUT_IDS else 'Game %s saves') % appid
+
+
+def plan():
+    parts = []
+    ids = ['saves:' + a for a in _prefixes()] + ['saves:linux', 'settings:steam', 'settings:system']
+    for part in ids:
+        files, skipped = part_files(part)
+        if not files:
+            continue
+        parts.append({'id': part, 'kind': part.split(':')[0], 'label': part_label(part),
+                      'files': len(files), 'bytes': sum(s for _, s in files), 'skipped': skipped,
+                      'appid': part[6:] if part[6:].isdigit() else None,
+                      'restorable': sum(1 for rel, _ in files
+                                        if any(_under(rel, r) for r in restore_roots(part, rel)))})
+    return {'build': os_release().get('BUILD_ID'), 'version': os_release().get('VERSION_ID'),
+            'parts': parts, 'excluded': EXCLUDED}
+
+
+def os_release():
+    out = {}
+    try:
+        for line in Path(os.environ.get('FRAME_BACKUP_OS_RELEASE') or '/etc/os-release').read_text().splitlines():
+            k, _, v = line.partition('=')
+            out[k.strip()] = v.strip().strip('"')
+    except OSError:
+        pass
+    return out
+
+
+def pack(part, output):
+    files, _ = part_files(part)
+    if len(files) > MAX_FILES or sum(s for _, s in files) > MAX_PART:
+        raise ValueError('this part is too big to back up (over 100,000 files or 20 GiB)')
+    with tarfile.open(fileobj=output, mode='w|gz') as archive:
+        for rel, _ in files:
+            path = HOME / rel
+            try:
+                with open(str(path), 'rb') as src:
+                    st = os.fstat(src.fileno())
+                    member = tarfile.TarInfo(rel)
+                    member.size, member.mtime, member.mode = st.st_size, int(st.st_mtime), st.st_mode & 0o755
+                    archive.addfile(member, src)
+            except OSError:
+                continue  # gone since the walk (a game wrote it); the manifest lists what's in the archive
+
+
+def target_status(part, rel):
+    """None if rel may be restored now, else why not (a short code)."""
+    if is_secret(rel) or not safe_rel(rel):
+        return 'refused'
+    if not any(_under(rel, r) for r in restore_roots(part, rel)):
+        return 'reference'
+    if part.startswith('saves:') and part != 'saves:linux':
+        appid = part[6:]
+        if int(appid) < SHORTCUT_IDS and \
+                not (HOME / STEAM / 'steamapps' / ('appmanifest_%s.acf' % appid)).is_file():
+            return 'not_installed'
+        if not (HOME / COMPAT / appid / PREFIX_USER).is_dir():
+            return 'no_prefix'
+    if part == 'settings:steam':
+        acct = re.search(r'/(\d+)/', rel[len(STEAM):])
+        if not acct or not (HOME / STEAM / 'userdata' / acct.group(1)).is_dir():
+            return 'no_account'
+    # A link anywhere on the way could send the write somewhere else.
+    path = HOME
+    for p in rel.split('/')[:-1]:
+        path = path / p
+        if path.is_symlink() or (path.exists() and not path.is_dir()):
+            return 'refused'
+    if (HOME / rel).is_symlink() or ((HOME / rel).exists() and not (HOME / rel).is_file()):
+        return 'refused'
+    return None
+
+
+def check(request):
+    out = []
+    for item in request.get('parts', []):
+        part, files = item.get('id'), item.get('files') or []
+        if not isinstance(part, str) or part_roots(part) is None:
+            out.append({'id': part, 'status': 'unknown'})
+            continue
+        counts = {}
+        replace = new = 0
+        for rel in files:
+            why = target_status(part, rel)
+            if why:
+                counts[why] = counts.get(why, 0) + 1
+            elif (HOME / rel).exists():
+                replace += 1
+            else:
+                new += 1
+        status = 'ok' if replace + new else next(
+            (c for c in ('not_installed', 'no_prefix', 'no_account', 'reference', 'refused') if c in counts), 'empty')
+        out.append({'id': part, 'status': status, 'replace': replace, 'new': new, 'held': counts})
+    return {'parts': out}
+
+
+def _sha256(path):
+    digest = hashlib.sha256()
+    with open(str(path), 'rb') as src:
+        for chunk in iter(lambda: src.read(1024 * 1024), b''):
+            digest.update(chunk)
+    return digest.hexdigest()
+
+
+def restore(part, stamp, source):
+    if part_roots(part) is None:
+        raise ValueError('unknown backup part %r' % part)
+    if not re.fullmatch(r'\d{8}-\d{6}', stamp):
+        raise ValueError('bad restore stamp')
+    # Spool first: everything is checked before anything is written.
+    spool_dir = HOME / '.cache/frame-control'
+    spool_dir.mkdir(parents=True, exist_ok=True)
+    written, replaced, held = [], [], {}
+    with tempfile.TemporaryDirectory(prefix='restore-', dir=str(spool_dir)) as tmp:
+        spool = Path(tmp) / 'part.tar.gz'
+        with open(str(spool), 'wb') as dst:
+            shutil.copyfileobj(source, dst, 1024 * 1024)
+        todo, names, total = [], set(), 0
+        with tarfile.open(str(spool), 'r:gz') as archive:
+            for member in archive:
+                if not member.isfile() or not safe_rel(member.name) or member.name in names:
+                    raise ValueError('backup has an unsafe, duplicate or non-file entry: %r' % member.name[:200])
+                names.add(member.name)
+                total += member.size
+                if len(names) > MAX_FILES or total > MAX_PART:
+                    raise ValueError('backup part is too big')
+                why = target_status(part, member.name)
+                if why:
+                    held[why] = held.get(why, 0) + 1
+                else:
+                    todo.append(member.name)
+        previous = HOME / PREVIOUS / stamp
+        keep = set(todo)
+        with tarfile.open(str(spool), 'r:gz') as archive:
+            for member in archive:
+                if member.name not in keep:
+                    continue
+                target = HOME / member.name
+                target.parent.mkdir(parents=True, exist_ok=True)
+                part_file = target.parent / ('.frame-restore-%d.part' % os.getpid())
+                with archive.extractfile(member) as src, open(str(part_file), 'wb') as dst:
+                    shutil.copyfileobj(src, dst, 1024 * 1024)
+                os.chmod(str(part_file), (member.mode & 0o755) | 0o600)
+                os.utime(str(part_file), (member.mtime, member.mtime))
+                if target.exists():
+                    if _sha256(target) == _sha256(part_file):
+                        os.unlink(str(part_file))
+                        held['same'] = held.get('same', 0) + 1
+                        continue
+                    keep_copy = previous / member.name
+                    keep_copy.parent.mkdir(parents=True, exist_ok=True)
+                    shutil.copy2(str(target), str(keep_copy))
+                    replaced.append(member.name)
+                os.replace(str(part_file), str(target))
+                written.append(member.name)
+    return {'id': part, 'written': len(written), 'replaced': len(replaced), 'held': held,
+            'previous': (PREVIOUS + '/' + stamp) if replaced else None}
+
+
+# ---- Game Mode and Desktop Mode --------------------------------------------
+#
+# The Frame normally runs gamescope (Game Mode) with Plasma nested inside it as one panel
+# (steamos-nested-desktop). A full Desktop Mode session is SDDM autologin into Plasma
+# instead. Valve's own devkit tools (frame/devkit-utils: steamos-get-status, steamos-delete)
+# read the session from these files and switch with holo-session-select or
+# steamos-session-select, so that's what this reads and suggests.
+
+SDDM_CONFS = ('/etc/sddm.conf.d/zz-steamos-autologin.conf', '/etc/sddm.conf.d/steamos.conf')
+
+
+def _running(name, full=False):
+    try:
+        return subprocess.call(['pgrep', '-f' if full else '-x', name], stdout=subprocess.DEVNULL,
+                               stderr=subprocess.DEVNULL) == 0
+    except OSError:
+        return False
+
+
+def session():
+    configured, conf = None, None
+    for path in SDDM_CONFS:
+        try:
+            text = Path(path).read_text(errors='replace')
+        except OSError:
+            continue
+        m = re.search(r'^\s*Session\s*=\s*(\S+)', text, re.M)
+        conf, configured = path, (m.group(1) if m else None)
+        break
+    selector = next((s for s in ('holo-session-select', 'steamos-session-select') if shutil.which(s)), None)
+    # On the Frame gamescope's process is named gamescope-wl (seen on build 20261015.6141207),
+    # under the start-gamescope-session script.
+    gamescope = (_running('gamescope') or _running('gamescope-wl') or
+                 _running('start-gamescope-session', full=True))
+    plasma = _running('plasmashell')
+    nested = _running('steamos-nested-desktop', full=True)  # a script: its process name is the shell's
+    if gamescope:
+        mode = 'game'
+    elif plasma or (configured and 'plasma' in configured):
+        mode = 'desktop'
+    else:
+        mode = 'unknown'
+    return {'mode': mode, 'gamescope': gamescope, 'plasma': plasma, 'nested_desktop': nested,
+            'configured': configured, 'config_file': conf, 'selector': selector}
+
+
+def main(argv):
+    cmd, args = (argv[0] if argv else ''), argv[1:]
+    try:
+        if cmd == 'plan':
+            print(json.dumps(plan()))
+        elif cmd == 'pack' and len(args) == 1:
+            out = sys.stdout.buffer
+            pack(args[0], out)
+            out.flush()
+        elif cmd == 'check':
+            print(json.dumps(check(json.load(sys.stdin))))
+        elif cmd == 'restore' and len(args) == 2:
+            print(json.dumps(restore(args[0], args[1], sys.stdin.buffer)))
+        elif cmd == 'session':
+            print(json.dumps(session()))
+        else:
+            sys.stderr.write('usage: plan | pack PART | check | restore PART STAMP | session\n')
+            return 2
+    except (OSError, ValueError, tarfile.TarError) as error:
+        sys.stderr.write(str(error) + '\n')
+        return 1
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv[1:]))

ui/frame_macview.py

@@ -56,12 +56,12 @@ BROWSER_FLAGS = []
 PANEL_BOX = (1920, 1080)
 
 # Opens one viewer on gamescope's X display and gives its window its own panel
-# id. Args: appid url width height tag [browser flags...]. The page puts "[tag]" in its title at
+# id. Args: appid url width height tag profile [browser flags...]. The page puts "[tag]" in its title at
 # once, which is how its X window is found (Chromium may hand the URL to an
 # instance that's already running, so there's no process to follow).
 LAUNCH = r"""set -u
-appid=$1 url=$2 w=$3 h=$4 tag=$5
-shift 5
+appid=$1 url=$2 w=$3 h=$4 tag=$5 profile=$6
+shift 6
 export DISPLAY=:0 LC_ALL=C.UTF-8
 unset WAYLAND_DISPLAY
 if ! xprop -root GAMESCOPE_FOCUSABLE_WINDOWS >/dev/null 2>&1; then
@@ -73,15 +73,15 @@ common=(--ozone-platform=x11 --force-device-scale-factor=1 --no-first-run --no-d
   --disable-features=Translate,MediaRouter --autoplay-policy=no-user-gesture-required
   "--window-size=$w,$h" "$@" "--app=$url")
 if [ -x "$HOME/chromium-xr/chrome" ]; then
-  cmd=("$HOME/chromium-xr/chrome" "--user-data-dir=$HOME/.local/share/frame-control/mac-view" "${common[@]}")
+  cmd=("$HOME/chromium-xr/chrome" "--user-data-dir=$HOME/.local/share/frame-control/$profile" "${common[@]}")
 elif flatpak info org.chromium.Chromium >/dev/null 2>&1; then
   cmd=(flatpak run org.chromium.Chromium
-    "--user-data-dir=$HOME/.var/app/org.chromium.Chromium/data/frame-mac-view" "${common[@]}")
+    "--user-data-dir=$HOME/.var/app/org.chromium.Chromium/data/frame-$profile" "${common[@]}")
 else
   echo "NO_BROWSER"
   exit 3
 fi
-log=/tmp/frame-mac-view.log
+log=/tmp/frame-$profile.log
 setsid nohup "${cmd[@]}" >>"$log" 2>&1 </dev/null &
 for _ in $(seq 1 60); do
   sleep 0.5
@@ -105,9 +105,9 @@ class MacViewError(Exception):
     pass
 
 
-def panel_id(src):
+def panel_id(src, host="mac"):
     """A stable panel id per source, in the range panel-on-frame.sh uses."""
-    return 2_001_000_000 + zlib.crc32(f"mac:{src}".encode()) % 1_000_000
+    return 2_001_000_000 + zlib.crc32(f"{host}:{src}".encode()) % 1_000_000
 
 
 def fit(w, h, box=PANEL_BOX):
@@ -116,6 +116,9 @@ def fit(w, h, box=PANEL_BOX):
 
 
 class MacView:
+    host = "mac"
+    viewer_profile = "mac-view"
+
     def __init__(self, tunnel_ssh, run, frame, track=None):
         self.tunnel_ssh = list(tunnel_ssh)
         self.run = run
@@ -174,6 +177,12 @@ class MacView:
         except OSError:
             return False
 
+    def agent_command(self):
+        return [str(AGENT)]
+
+    def agent_environment(self):
+        return {**os.environ, "FRAME_MAC_VIEW_TOKEN": self.token}
+
     def ensure_agent(self):
         with self.lock:
             if self.agent and self.agent.poll() is None:
@@ -182,11 +191,11 @@ class MacView:
             if reason:
                 raise MacViewError(reason)
             self.build()
-            env = {**os.environ, "FRAME_MAC_VIEW_TOKEN": self.token}
+            env = self.agent_environment()
             # The same port as before when restarting, so a running tunnel still
             # fits; otherwise (or if it's gone) whatever the system gives.
             for port in dict.fromkeys([self.port or 0, 0]):
-                self.agent = subprocess.Popen([str(AGENT), "serve", "--port", str(port), "--page", str(PAGE),
+                self.agent = subprocess.Popen([*self.agent_command(), "serve", "--port", str(port), "--page", str(PAGE),
                                                "--exit-on-eof"], env=env, stdin=subprocess.PIPE,
                                               stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True)
                 line = self.agent.stdout.readline()
@@ -195,7 +204,7 @@ class MacView:
                     break
                 self.agent.kill()
             else:
-                raise MacViewError(f"The Mac streaming helper didn't start: {line.strip() or 'no output'}")
+                raise MacViewError(f"The streaming helper didn't start: {line.strip() or 'no output'}")
             if self.port != int(m.group(1)):
                 self._drop_tunnel()
             self.port = int(m.group(1))
@@ -211,7 +220,7 @@ class MacView:
             with urllib.request.urlopen(req, timeout=10) as r:
                 return json.load(r)
         except (urllib.error.URLError, OSError, ValueError) as e:
-            raise MacViewError(f"The Mac streaming helper didn't answer: {e}")
+            raise MacViewError(f"The streaming helper didn't answer: {e}")
 
     # ---- the tunnel from the Frame ----
 
@@ -396,7 +405,7 @@ class MacView:
         # the agent no longer counts them, so only move when none are out there.
         others = self.shown - {src}
         self.ensure_tunnel(allow_new_port=not others)
-        appid = panel_id(src)
+        appid = panel_id(src, self.host)
         # Unique per launch, so a new window is never confused with an old one.
         tag = "fc" + secrets.token_hex(4)
         # A single-use ticket for this source, not Frame Control's key: the URL
@@ -406,7 +415,7 @@ class MacView:
                   "bpp": q["bpp"]}
         url = f"http://127.0.0.1:{self.remote_port}/view?{urlencode(params)}"
         w, h = fit(width or 1280, height or 720)
-        args = " ".join(_quote(str(a)) for a in (appid, url, w, h, tag, *self.browser_flags))
+        args = " ".join(_quote(str(a)) for a in (appid, url, w, h, tag, self.viewer_profile, *self.browser_flags))
         try:
             out = self.run("bash -s -- " + args, stdin=LAUNCH, timeout=60)
         except Exception as e:  # noqa: BLE001 - the server's Failure carries the Frame's words
@@ -438,7 +447,8 @@ class MacView:
             if self.shown or self.shows != shows or self.launching:
                 return
             try:
-                self.run("pkill -f '[f]rame-control/mac-view|[d]ata/frame-mac-view' || true", timeout=10)
+                pattern = "[f]rame-control/" + self.viewer_profile + "|[d]ata/frame-" + self.viewer_profile
+                self.run("pkill -f " + _quote(pattern) + " || true", timeout=10)
             except Exception:
                 pass
 
@@ -449,7 +459,8 @@ class MacView:
         status = self.call("/status")
         windows = self.call("/windows").get("windows", []) if status.get("screen") else []
         displays = self.call("/displays").get("displays", [])
-        return {"available": True, "screen": status.get("screen", False),
+        return {"available": True, "host": self.host, "selecting": status.get("selecting", False),
+                "selectionError": status.get("selectionError", ""), "screen": status.get("screen", False),
                 "accessibility": status.get("accessibility", False), "streams": status.get("streams", []),
                 "windows": windows, "displays": displays, "tunnel": self.tunnel_up(),
                 "route": self.route}

ui/frame_pc_agent.py

@@ -0,0 +1,624 @@
+#!/usr/bin/env python3
+"""Frame Control's Windows/Linux host. Same ticket, H.264/JPEG, timing and
+input protocol as frame-mac-view; serves the same ui/mac-view.html.
+
+Only loopback is bound. Frame Control owns the master token, the Frame gets
+one-source tickets and reconnect keys. Native libraries are bundled.
+"""
+import argparse
+import base64
+import ctypes as C
+import hashlib
+from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
+import json
+import math
+import os
+import queue
+from pathlib import Path
+import secrets
+import socket
+import struct
+import sys
+import threading
+import time
+from urllib.parse import parse_qs, urlsplit
+
+from frame_pc_capture import Native, Controller, Windows, WindowsInput, PortalInput, Encoded, GATE, dimensions, pipeline
+from frame_stream_stats import Stats
+
+
+# Viewer fields are untrusted JSON: float('x'), int(None), m['t'] missing.
+MALFORMED = (ValueError, TypeError, KeyError, OverflowError)
+
+
+class Grants:
+    """Caller holds the agent lock, including replacement and Stop."""
+    def __init__(self, token):
+        self.token, self.tickets, self.keys = token, {}, {}
+
+    def master(self, key):
+        return isinstance(key, str) and secrets.compare_digest(key, self.token)
+
+    def ticket(self, src):
+        self.tickets = {k: v for k, v in self.tickets.items() if v[1] > time.monotonic()}
+        if len(self.tickets) >= 128:
+            raise ValueError('Too many pending viewers')
+        ticket = secrets.token_urlsafe(24)
+        self.tickets[ticket] = (src, time.monotonic()+60, None)
+        return ticket
+
+    def redeem(self, src, q):
+        if self.master(q.get('k')):
+            key = secrets.token_urlsafe(24)
+            self.keys[key] = src
+            return key
+        entry = self.tickets.get(q.get('t'))
+        if entry and entry[0] == src and entry[1] > time.monotonic():
+            key = entry[2] or secrets.token_urlsafe(24)
+            self.tickets[q['t']] = (src, entry[1], key)
+            self.keys[key] = src
+            return key
+        key = q.get('r')
+        return key if key and self.keys.get(key) == src else None
+
+    def ack(self, key):
+        self.tickets = {k: v for k, v in self.tickets.items() if v[2] != key}
+
+    def revoke(self, src=None):
+        self.tickets = {k: v for k, v in self.tickets.items() if src is not None and v[0] != src}
+        self.keys = {k: v for k, v in self.keys.items() if src is not None and v != src}
+
+
+class WebSocket:
+    def __init__(self, handler):
+        self.sock, self.reader = handler.connection, handler.rfile
+        self.lock = threading.Lock()
+        self.closed = False
+        self.sock.settimeout(5)
+        self.sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
+
+    def send(self, data, opcode=1):
+        if not isinstance(data, bytes):
+            data = json.dumps(data, separators=(',', ':')).encode()
+        n = len(data)
+        head = bytes([0x80 | opcode, n]) if n < 126 else bytes([0x80 | opcode, 126]) + struct.pack('!H', n) if n <= 65535 else bytes([0x80 | opcode, 127]) + struct.pack('!Q', n)
+        with self.lock:
+            if self.closed:
+                raise ConnectionError('Viewer disconnected')
+            self.sock.sendall(head + data)
+
+    def exact(self, n):
+        data = self.reader.read(n)
+        if len(data) != n:
+            raise ConnectionError('Viewer disconnected')
+        return data
+
+    def receive(self):
+        a, b = self.exact(2)
+        opcode, size = a & 15, b & 127
+        if a & 0x70 or not a & 0x80 or not b & 0x80 or opcode not in (1, 8, 9, 10):
+            raise ValueError('Unsupported WebSocket frame')
+        if size == 126:
+            size = struct.unpack('!H', self.exact(2))[0]
+        elif size == 127:
+            size = struct.unpack('!Q', self.exact(8))[0]
+        if size > 65536 or (opcode >= 8 and size > 125):
+            raise ValueError('WebSocket message too large')
+        mask = self.exact(4)
+        data = bytes(v ^ mask[i % 4] for i, v in enumerate(self.exact(size)))
+        if opcode == 8:
+            raise ConnectionError('Viewer closed')
+        if opcode == 9:
+            self.send(data, 10)
+        if opcode != 1:
+            return {}
+        message = json.loads(data)
+        if not isinstance(message, dict):
+            raise ValueError('Expected an input object')
+        return message
+
+    def close(self):
+        self.closed = True
+        try:
+            self.sock.shutdown(socket.SHUT_RDWR)
+        except OSError:
+            pass
+
+
+class Session:
+    def __init__(self, agent, ws, key, source, query):
+        self.agent, self.native, self.ws, self.key, self.source = agent, agent.native, ws, key, source
+        self.src = source['src']
+        self.codec = query.get('codec', 'h264')
+        if self.codec not in ('h264', 'jpeg'):
+            raise ValueError('Unsupported codec')
+        self.fps = min(120, max(5, int(query.get('fps', 60))))
+        bpp = float(query.get('bpp', .1))
+        if not math.isfinite(bpp):
+            raise ValueError('Invalid bitrate')
+        self.w, self.h = dimensions(source['w'], source['h'], min(3840, max(320, int(query.get('max', 1920)))))
+        self.bitrate = max(300000, int(self.w*self.h*self.fps*min(.5, max(.02, bpp))))
+        self.controller = Controller(self.native.lib, self.fps, self.bitrate)
+        self.stats = Stats(self.native.now)
+        self.stop_event, self.key_event = threading.Event(), threading.Event()
+        self.lock, self.input_lock = threading.RLock(), threading.RLock()
+        self.pending, self.last_submit = {}, 0
+        self.reconfiguring = False
+        self.test_inputs = queue.Queue(maxsize=128)
+        self.input = None if self.src == 'test' else WindowsInput(agent.windows, source) if agent.windows else PortalInput(self.native, source)
+        self.writer = None
+        self.released = False
+        self.input_enabled = self.src == 'test' or self.source.get('devices', 3) == 3
+
+    def gate(self, stage, pts, capture, arrived):
+        # Exceptions cannot cross a ctypes callback boundary.
+        try:
+            with self.lock:
+                if self.stop_event.is_set() or self.reconfiguring:
+                    return -1
+                if stage == 1:
+                    if pts in self.pending:
+                        self.pending[pts]['e0'] = self.native.now()
+                    return 1
+                if stage == 0:
+                    self.stats.captured += 1
+                    self.controller.call('capture', arrived)
+                now = self.native.now()
+                state = self.controller.state()
+                if len(self.pending) >= 3 or now-self.last_submit < 1000000/state['fps'] or not self.controller.call('gate', now, int(stage == 0)):
+                    if stage == 0:
+                        self.stats.skipped += 1
+                    return 0
+                self.pending[pts] = dict(cap=capture, arr=arrived, e0=now, tier=state['tier'], br=state['target'])
+                self.last_submit = now
+                return 1
+        except Exception:
+            self.stop_event.set()
+            return -1
+
+    STALL = 10000000
+
+    def stalled(self, now, opened, captured_at_open):
+        """PipeWire and WGC deliver frames only on screen damage, so an idle
+        desktop legitimately produces no output. Fail only on evidence of a
+        fault: a frame entered the encoder and never came out, or the capture
+        never produced its initial frame after the pipeline opened."""
+        with self.lock:
+            oldest = min((r['e0'] for r in self.pending.values()), default=None)
+            captured = self.stats.captured
+        if oldest is not None and now-oldest > self.STALL:
+            return 'The encoder stopped producing frames; check the video encoder'
+        if captured == captured_at_open and now-opened > self.STALL:
+            return 'No frames captured for 10 seconds; check capture permissions'
+        return None
+
+    def fresh_pipewire(self):
+        if 'portal' not in self.source:
+            return
+        error = C.create_string_buffer(1024)
+        fd = self.native.lib.fc_portal_refresh(self.source['portal'], error, len(error))
+        if fd < 0:
+            raise RuntimeError(error.value.decode(errors='replace'))
+        self.source['fd'] = fd
+
+    def produce(self):
+        native, capture = self.native.lib, None
+        try:
+            encoder = "x264enc" if self.src == "test" and self.native.has("x264enc") else self.agent.encoder
+            self.fresh_pipewire()
+            description = pipeline(self.source, sys.platform, encoder, self.w, self.h, self.fps, self.bitrate, self.codec)
+            self.callback = GATE(self.gate)
+            error = C.create_string_buffer(1024)
+            capture = native.fc_capture_open(description.encode(), self.callback, error, len(error))
+            if not capture:
+                raise RuntimeError(error.value.decode(errors='replace'))
+            last_update = last_stats = self.native.now()
+            last_config = opened = last_update
+            captured_at_open = self.stats.captured
+            applied = (self.w, self.h, self.bitrate)
+            wanted = applied
+            while not self.stop_event.is_set():
+                while not self.test_inputs.empty():
+                    event = self.test_inputs.get_nowait()
+                    try:
+                        native.fc_capture_test(capture, int(event.get('i', 0)) & 0xffffffff)
+                        self.stats.input(event)
+                    except MALFORMED:
+                        pass  # a bad probe field drops the event, not the stream
+                output = Encoded()
+                result = native.fc_capture_pull(capture, C.byref(output))
+                now = self.native.now()
+                if result < 0:
+                    raise RuntimeError(native.fc_capture_error(capture).decode(errors='replace'))
+                if result:
+                    with self.lock:
+                        # At most three raw frames are in flight; no B-frames.
+                        # x264 offsets PTS, so match the FIFO encode order while
+                        # retaining the actual pre-encode capture timestamp.
+                        raw_pts = next(iter(self.pending), None)
+                        record = self.pending.get(raw_pts)
+                        if record is None:
+                            raise RuntimeError('Encoder changed frame timestamps; timing cannot be matched')
+                        data = C.string_at(output.data, output.size)
+                        f = self.stats.add(**record, e1=now, snd=now, b=len(data), k=output.key,
+                                           w=output.width or self.w, h=output.height or self.h)
+                        self.controller.call('sent', f['s'], len(data)+17, now)
+                    self.ws.send(struct.pack('!BQII', output.key, max(0, f['cap']), f['s'], f['echo'])+data, 2)
+                    with self.lock:
+                        f['wire'] = self.native.now()
+                        self.pending.pop(raw_pts, None)
+                stall = self.stalled(now, opened, captured_at_open)
+                if stall:
+                    raise RuntimeError(stall)
+                if self.key_event.is_set():
+                    self.key_event.clear()
+                    if self.codec == 'h264':
+                        native.fc_capture_key(capture)
+                if now-last_update >= 100000:
+                    target = self.controller.update(now)
+                    state = self.controller.state()
+                    w, h = dimensions(self.w, self.h, max(320, int(max(self.w, self.h)*state['scale'])))
+                    if target and self.codec == 'h264' and encoder == 'x264enc':
+                        native.fc_capture_bitrate(capture, target)
+                        self.bitrate = target
+                    # Hardware properties are not uniformly mutable in PLAYING.
+                    # Drain then reopen the pipeline at a keyframe when its
+                    # budget changes materially. The portal fd/session stays
+                    # alive, so this does not bypass or repeat user consent.
+                    desired_bitrate = target or applied[2]
+                    bitrate_change = self.codec == 'h264' and encoder != 'x264enc' and abs(desired_bitrate-applied[2]) > applied[2]*.2
+                    if not self.reconfiguring and now-last_config >= 1000000 and ((w, h) != applied[:2] or bitrate_change):
+                        wanted = (w, h, desired_bitrate)
+                        with self.lock:
+                            self.reconfiguring = True
+                    last_update = now
+                if self.reconfiguring:
+                    with self.lock:
+                        drained = not self.pending
+                    if drained:
+                        native.fc_capture_close(capture)
+                        capture = None
+                        self.fresh_pipewire()
+                        description = pipeline(self.source, sys.platform, encoder, wanted[0], wanted[1], self.fps, wanted[2], self.codec)
+                        capture = native.fc_capture_open(description.encode(), self.callback, error, len(error))
+                        if not capture:
+                            raise RuntimeError(error.value.decode(errors='replace'))
+                        applied, self.bitrate, last_config = wanted, wanted[2], now
+                        opened, captured_at_open = now, self.stats.captured
+                        with self.lock:
+                            self.reconfiguring = False
+                if now-last_stats >= 1000000:
+                    self.ws.send(dict(self.stats.summary(), t='stats', bitrate=self.bitrate,
+                                      size='%dx%d' % (self.w, self.h), tier=self.controller.state()['tier']))
+                    last_stats = now
+        except Exception as e:
+            try:
+                self.ws.send({'t': 'error', 'message': str(e)})
+            except OSError:
+                pass
+        finally:
+            self.stop_event.set()
+            if capture:
+                native.fc_capture_close(capture)
+            self.ws.close()
+
+    def start(self):
+        if self.stop_event.is_set():
+            self.controller.close()
+            return
+        self.ws.send(dict(t='hello', r=self.key))
+        self.ws.send(dict(t='info', src=self.src, title=self.source.get('title', self.source.get('name', 'Test pattern')),
+                          app='PC', codec=self.codec, input=self.input_enabled,
+                          inputMessage='Allow pointer and keyboard control in the host sharing dialog.',
+                          aspect=self.w/self.h, warm=0))
+        with self.lock:
+            if self.stop_event.is_set():
+                self.controller.close()
+                return
+            self.writer = threading.Thread(target=self.produce, daemon=True)
+            self.writer.start()
+        try:
+            while not self.stop_event.is_set():
+                m = self.ws.receive()
+                t = m.get('t')
+                if t == 'ping':
+                    self.ws.send(dict(t='pong', c=m.get('c', 0), a=self.native.now()))
+                elif t == 'ack':
+                    with self.agent.lock:
+                        self.agent.grants.ack(self.key)
+                elif t == 'key-frame':
+                    self.key_event.set()
+                elif t in ('rx', 'fd', 'clock'):
+                    try:
+                        self.stats.report(m)
+                    except MALFORMED:
+                        pass
+                    if t == 'rx' and isinstance(m.get('s'), int):
+                        self.controller.call('ack', m['s'] & 0xffffffff, self.native.now())
+                elif t in ('m', 'wheel', 'k', 'text', 'release'):
+                    with self.input_lock:
+                        if self.stop_event.is_set():
+                            break
+                        if self.input:
+                            if not self.input_enabled and t != 'release':
+                                continue
+                            try:
+                                self.input.handle(m)
+                                self.stats.input(m)
+                            except MALFORMED:
+                                pass  # drop a malformed viewer event; keep the session
+                            except RuntimeError as e:
+                                self.input_enabled = False
+                                try:
+                                    self.input.release()
+                                except RuntimeError:
+                                    pass
+                                self.ws.send(dict(t='error', message=str(e)))
+                        elif m.get('i'):
+                            try:
+                                self.test_inputs.put_nowait(m)
+                            except queue.Full:
+                                pass
+        finally:
+            self.end()
+            self.writer.join(6)
+            if not self.writer.is_alive():
+                self.controller.close()
+
+    def end(self):
+        with self.lock:
+            self.stop_event.set()
+        self.ws.close()
+        with self.input_lock:
+            if self.input and not self.released:
+                self.released = True
+                try:
+                    self.input.release()
+                except (RuntimeError, OSError):
+                    pass
+
+
+class Agent:
+    def __init__(self, native, token, page):
+        self.native, self.page = native, page
+        self.lock = threading.RLock()
+        self.grants = Grants(token)
+        self.sessions, self.sources = {}, {}
+        self.next_id, self.selecting, self.selection_error = 1, False, ''
+        self.windows = Windows() if sys.platform == 'win32' else None
+        self.encoder = 'mfh264enc' if self.windows else 'vah264enc' if native.has('vah264enc') else 'x264enc'
+        self.shutting_down = False
+        self.selection_generation = 0
+
+    def lists(self):
+        if self.windows:
+            windows, displays = self.windows.sources()
+            self.sources = {s['src']: s for s in windows + displays}
+            return windows, displays
+        return [{k: v for k, v in s.items() if k not in ('portal', 'fd', 'node')} for s in self.sources.values()], []
+
+    def source(self, src):
+        if src == 'test':
+            return dict(src='test', title='Test pattern', w=1280, h=720)
+        self.lists()
+        if src not in self.sources:
+            raise ValueError('Choose a window or screen on this computer first')
+        return dict(self.sources[src])
+
+    def select(self):
+        if self.windows or self.selecting or self.shutting_down:
+            return
+        if len(self.sources) >= 8:
+            raise ValueError('Stop a panel before sharing another source')
+        self.selecting, self.selection_error = True, ''
+        generation = self.selection_generation
+        def choose():
+            error = C.create_string_buffer(1024)
+            portal = self.native.lib.fc_portal_select(error, len(error))
+            with self.lock:
+                self.selecting = False
+                if not portal:
+                    self.selection_error = error.value.decode(errors='replace')
+                elif self.shutting_down or generation != self.selection_generation:
+                    self.native.lib.fc_portal_close(portal)
+                else:
+                    fd, node, w, h, devices = [self.native.lib.fc_portal_value(portal, i) for i in range(5)]
+                    src = 'window:' + secrets.token_hex(8)
+                    self.sources[src] = dict(src=src, title='Shared window or screen', app='Linux portal',
+                                             w=w, h=h, fd=fd, node=node, portal=portal, devices=devices)
+        threading.Thread(target=choose, daemon=True).start()
+
+    def stop(self, src=None):
+        with self.lock:
+            if src is None:
+                self.selection_generation += 1
+            self.grants.revoke(src)
+            sessions = [s for s in self.sessions.values() if src is None or s.src == src]
+            for session in sessions:
+                try:
+                    session.ws.send(dict(t='close'))
+                except OSError:
+                    pass
+                session.end()
+        for session in sessions:
+            if session.writer and session.writer is not threading.current_thread():
+                session.writer.join(6)
+        # The capture is stopped before releasing its PipeWire fd/session.
+        with self.lock:
+            if not self.windows:
+                for key, source in list(self.sources.items()):
+                    if src is None or key == src:
+                        if any(s.src == key and s.writer and s.writer.is_alive() for s in sessions):
+                            continue
+                        self.native.lib.fc_portal_close(source['portal'])
+                        self.sources.pop(key, None)
+        return {'closed': len(sessions)}
+
+
+class Handler(BaseHTTPRequestHandler):
+    protocol_version = 'HTTP/1.1'
+
+    def log_message(self, *args):
+        pass  # URLs contain credentials
+
+    def reply(self, data, status=200, content='application/json'):
+        if not isinstance(data, bytes):
+            data = json.dumps(data).encode()
+        self.send_response(status)
+        self.send_header('Content-Type', content)
+        self.send_header('Content-Length', str(len(data)))
+        self.send_header('Cache-Control', 'no-store')
+        self.send_header('Connection', 'close')
+        self.end_headers()
+        self.wfile.write(data)
+        self.close_connection = True
+
+    def do_GET(self):
+        self.dispatch('GET')
+
+    def do_POST(self):
+        self.dispatch('POST')
+
+    def dispatch(self, method):
+        agent = self.server.agent
+        url = urlsplit(self.path)
+        q = {k: v[-1] for k, v in parse_qs(url.query).items()}
+        try:
+            if method == 'GET' and url.path == '/ping':
+                return self.reply(b'frame-mac-view', content='text/plain')
+            if method == 'GET' and url.path == '/view':
+                return self.reply(agent.page.read_bytes(), content='text/html; charset=utf-8')
+            if method == 'GET' and url.path == '/stream':
+                return self.stream(q)
+            if not agent.grants.master(q.get('k', self.headers.get('X-Token'))):
+                return self.reply({'error': 'forbidden'}, 403)
+            if method == 'POST' and url.path == '/close':
+                return self.reply(agent.stop(q.get('src')))
+            with agent.lock:
+                windows, displays = agent.lists()
+                if method == 'GET' and url.path == '/status':
+                    data = dict(version=1, host='windows' if agent.windows else 'linux', screen=True,
+                                accessibility=True, selecting=agent.selecting, selectionError=agent.selection_error,
+                                encoder=agent.encoder, finished=[], streams=[dict(id=i, src=s.src,
+                                    title=s.source.get('title', ''), stats=s.stats.summary(), controller=s.controller.state())
+                                    for i, s in agent.sessions.items() if not s.stop_event.is_set()])
+                elif method == 'GET' and url.path in ('/windows', '/displays'):
+                    data = dict(windows=windows, displays=displays, screen=True)
+                elif method == 'POST' and url.path == '/ticket':
+                    agent.source(q.get('src'))
+                    data = {'ticket': agent.grants.ticket(q['src'])}
+                elif method == 'POST' and url.path == '/permissions':
+                    agent.select()
+                    data = {'selecting': agent.selecting}
+                elif method == 'GET' and url.path == '/stats':
+                    data = dict(now=agent.native.now(), streams=[dict(id=i, src=s.src, controller=s.controller.state(),
+                         events=list(s.controller.events), **s.stats.snapshot(max(0, int(q.get('since', 0))), max(0, int(q.get('settle', 1500000)))))
+                         for i, s in agent.sessions.items() if q.get('id', str(i)) == str(i) and not s.stop_event.is_set()])
+                elif method == 'POST' and url.path == '/bench':
+                    data = {'sent': 0}
+                    for s in agent.sessions.values():
+                        if s.src == q.get('src'):
+                            m = {k: v for k, v in q.items() if k not in ('k', 'src')}
+                            for k in ('x', 'y', 'interval'):
+                                if k in m:
+                                    m[k] = float(m[k])
+                            s.ws.send(dict(m, t='bench'))
+                            data['sent'] += 1
+                else:
+                    return self.reply({'error': 'not found'}, 404)
+            self.reply(data)
+        except (ValueError, RuntimeError) as e:
+            self.reply({'error': str(e)}, 400)
+        except (OSError, ConnectionError):
+            self.close_connection = True
+
+    def stream(self, query):
+        agent = self.server.agent
+        with agent.lock:
+            key = agent.grants.redeem(query.get('src'), query)
+            if not key:
+                return self.reply({'error': 'forbidden'}, 403)
+            source = agent.source(query.get('src'))
+            if self.headers.get('Upgrade', '').lower() != 'websocket' or self.headers.get('Sec-WebSocket-Version') != '13':
+                return self.reply({'error': 'expected WebSocket'}, 400)
+            wskey = self.headers.get('Sec-WebSocket-Key', '')
+            if len(base64.b64decode(wskey, validate=True)) != 16:
+                raise ValueError('Bad WebSocket key')
+            if len(agent.sessions) >= 8:
+                raise ValueError('At most eight panels may be open')
+            # Stop can revoke and close only a registered session. Register
+            # under the same lock as redemption, before any capture starts.
+            session = Session(agent, WebSocket(self), key, source, query)
+            for old in list(agent.sessions.values()):
+                if old.key == key or old.src == source['src']:
+                    if old.key != key:
+                        agent.grants.keys.pop(old.key, None)
+                        try:
+                            old.ws.send(dict(t='close'))
+                        except OSError:
+                            pass
+                    old.end()
+                    if old.writer:
+                        old.writer.join(6)
+                        if old.writer.is_alive():
+                            session.controller.close()
+                            raise ValueError('The previous capture is still stopping; retry shortly')
+            ident = agent.next_id
+            agent.next_id += 1
+            agent.sessions[ident] = session
+            accept = base64.b64encode(hashlib.sha1((wskey+'258EAFA5-E914-47DA-95CA-C5AB0DC85B11').encode()).digest()).decode()
+            self.send_response(101)
+            self.send_header('Upgrade', 'websocket')
+            self.send_header('Connection', 'Upgrade')
+            self.send_header('Sec-WebSocket-Accept', accept)
+            self.end_headers()
+        try:
+            session.start()
+        except (OSError, ValueError, RuntimeError):
+            session.end()
+        finally:
+            session.end()
+            if session.writer:
+                session.writer.join(6)
+            if not session.writer or not session.writer.is_alive():
+                session.controller.close()
+            with agent.lock:
+                agent.sessions.pop(ident, None)
+            self.close_connection = True
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('command', choices=['serve'])
+    parser.add_argument('--port', type=int, default=0)
+    parser.add_argument('--page', type=Path, required=True)
+    parser.add_argument('--exit-on-eof', action='store_true')
+    args = parser.parse_args()
+    token = os.environ.get('FRAME_MAC_VIEW_TOKEN')
+    if not token:
+        raise SystemExit('Frame Control must provide a private token')
+    native = Native()
+    server = ThreadingHTTPServer(('127.0.0.1', args.port), Handler)
+    agent = server.agent = Agent(native, token, args.page)
+    if args.exit_on_eof:
+        def eof():
+            sys.stdin.buffer.read()
+            with agent.lock:
+                agent.shutting_down = True
+            agent.stop()
+            server.shutdown()
+        threading.Thread(target=eof, daemon=True).start()
+    print('listening on 127.0.0.1:%d' % server.server_port, flush=True)
+    try:
+        server.serve_forever()
+    finally:
+        agent.shutting_down = True
+        agent.stop()
+        server.server_close()
+
+
+if __name__ == '__main__':
+    try:
+        main()
+    except (OSError, RuntimeError, AttributeError) as e:
+        raise SystemExit('PC streaming helper: ' + str(e))

ui/frame_pc_capture.py

@@ -0,0 +1,383 @@
+"""Native PC capture and input bindings. No desktop-streaming app required.
+
+The packaged native library contains our adapter and the shared rate controller;
+GStreamer supplies WGC/Media Foundation and PipeWire/VA-API/x264 libraries.
+"""
+import ctypes as C
+import os
+from pathlib import Path
+import re
+import sys
+import threading
+
+ROOT = Path(__file__).resolve().parent.parent
+NATIVE = Path(os.environ.get('FRAME_PC_NATIVE', ROOT / 'desktop' / 'bundle'))
+LIBRARY = NATIVE / ('pc-host.dll' if sys.platform == 'win32' else 'pc-host.so')
+
+
+class Encoded(C.Structure):
+    _fields_ = [('data', C.c_void_p), ('size', C.c_int), ('key', C.c_int),
+                ('width', C.c_int), ('height', C.c_int), ('pts', C.c_int64)]
+
+
+GATE = C.CFUNCTYPE(C.c_int, C.c_int, C.c_int64, C.c_int64, C.c_int64)
+
+
+class Native:
+    def __init__(self, path=LIBRARY):
+        self.dll_dirs = []
+        if sys.platform == 'win32':
+            # Set process coordinates before loading GStreamer: a plugin may
+            # create a helper HWND during discovery, after which it is too late.
+            user = C.WinDLL('user32')
+            user.SetProcessDpiAwarenessContext.argtypes = [C.c_void_p]
+            user.SetProcessDpiAwarenessContext(C.c_void_p(-4))
+            for folder in (path.parent, path.parent / 'bin'):
+                self.dll_dirs.append(os.add_dll_directory(str(folder)))
+        self.lib = C.CDLL(str(path))
+        signatures = {
+            'fc_now': (C.c_int64, []), 'fc_gst_init': (None, []),
+            'fc_has_element': (C.c_int, [C.c_char_p]),
+            'fc_new': (C.c_void_p, [C.c_int, C.c_int]), 'fc_free': (None, [C.c_void_p]),
+            'fc_ceiling': (None, [C.c_void_p, C.c_int]),
+            'fc_gate': (C.c_int, [C.c_void_p, C.c_int64, C.c_int]),
+            'fc_capture': (None, [C.c_void_p, C.c_int64]),
+            'fc_sent': (None, [C.c_void_p, C.c_uint32, C.c_int, C.c_int64]),
+            'fc_ack': (C.c_int, [C.c_void_p, C.c_uint32, C.c_int64]),
+            'fc_update': (C.c_int, [C.c_void_p, C.c_int64]),
+            'fc_value': (C.c_int64, [C.c_void_p, C.c_int]),
+            'fc_capture_open': (C.c_void_p, [C.c_char_p, GATE, C.c_char_p, C.c_int]),
+            'fc_capture_pull': (C.c_int, [C.c_void_p, C.POINTER(Encoded)]),
+            'fc_capture_error': (C.c_char_p, [C.c_void_p]),
+            'fc_capture_bitrate': (None, [C.c_void_p, C.c_int]),
+            'fc_capture_key': (None, [C.c_void_p]),
+            'fc_capture_test': (None, [C.c_void_p, C.c_uint32]), 'fc_capture_close': (None, [C.c_void_p]),
+        }
+        if sys.platform.startswith('linux'):
+            signatures.update({
+                'fc_portal_select': (C.c_void_p, [C.c_char_p, C.c_int]),
+                'fc_portal_close': (None, [C.c_void_p]),
+                'fc_portal_refresh': (C.c_int, [C.c_void_p, C.c_char_p, C.c_int]),
+                'fc_portal_value': (C.c_int, [C.c_void_p, C.c_int]),
+                'fc_portal_input': (C.c_int, [C.c_void_p, C.c_int, C.c_double, C.c_double, C.c_int, C.c_int]),
+            })
+        for name, (result, args) in signatures.items():
+            fn = getattr(self.lib, name)
+            fn.restype, fn.argtypes = result, args
+        self.lib.fc_gst_init()
+
+    def has(self, name):
+        return bool(self.lib.fc_has_element(name.encode()))
+
+    def now(self):
+        return self.lib.fc_now()
+
+
+class Controller:
+    def __init__(self, lib, fps, ceiling):
+        # close() may run on the stream thread while /status reads state();
+        # after close every entry point is a no-op, never a NULL dereference.
+        self.lib, self.lock, self.fps = lib, threading.RLock(), fps
+        self.enabled = os.environ.get('FRAME_MAC_VIEW_ADAPT') != '0'
+        self.ptr = lib.fc_new(fps, self.enabled)
+        if not self.ptr:
+            raise MemoryError('Unable to allocate the streaming controller')
+        lib.fc_ceiling(self.ptr, ceiling)
+        self.events = []
+
+    def state(self):
+        with self.lock:
+            names = ['target', 'ceiling', 'tier', 'fps', 'scale', 'baseRtt', 'inFlight', 'slack']
+            if not self.ptr:
+                out = dict.fromkeys(names, 0)
+                out.update(fps=self.fps, scale=100)
+            else:
+                out = {k: self.lib.fc_value(self.ptr, i) for i, k in enumerate(names)}
+            out.update(scale=out['scale'] / 100, baseRtt=out['baseRtt'] / 1000,
+                       slack=out['slack'] / 1000, adapt=self.enabled)
+            return out
+
+    def call(self, name, *args):
+        with self.lock:
+            return getattr(self.lib, 'fc_' + name)(self.ptr, *args) if self.ptr else 0
+
+    def update(self, now):
+        with self.lock:
+            if not self.ptr:
+                return 0
+            old = self.state()
+            result = self.lib.fc_update(self.ptr, now)
+            state = self.state()
+            if state['target'] < old['target'] or state['tier'] != old['tier']:
+                self.events.append({'t': now, 'e': 'target %s bit/s; tier %s' % (state['target'], state['tier'])})
+                self.events = self.events[-200:]
+            return result
+
+    def close(self):
+        with self.lock:
+            if self.ptr:
+                self.lib.fc_free(self.ptr)
+                self.ptr = None
+
+
+def dimensions(w, h, maximum):
+    scale = min(1, maximum / max(w, h))
+    return max(2, int(w * scale) // 2 * 2), max(2, int(h * scale) // 2 * 2)
+
+
+def pipeline(source, platform, encoder, w, h, fps, bitrate, codec='h264'):
+    """Only locally constructed numeric source IDs enter the pipeline parser."""
+    if source['src'] == 'test':
+        capture = 'videotestsrc name=source is-live=true pattern=ball'
+    elif platform == 'win32':
+        kind, ident = source['src'].split(':')
+        if kind not in ('window', 'display') or not re.fullmatch(r'[0-9]+', ident):
+            raise ValueError('Invalid Windows capture source')
+        prop = 'window-handle' if kind == 'window' else 'monitor-handle'
+        capture = 'd3d11screencapturesrc capture-api=wgc show-cursor=true show-border=true %s=%d' % (prop, int(ident))
+    else:
+        capture = 'pipewiresrc fd=%d path=%d do-timestamp=true' % (source['fd'], source['node'])
+    # The source gate runs before conversion/encoding. There is no leaky queue
+    # of H.264 frames; every encoded reference frame reaches the socket.
+    raw = '%s ! video/x-raw,framerate=%d/1 ! queue name=raw_queue leaky=downstream max-size-buffers=1 max-size-bytes=0 max-size-time=0 ! identity name=gate ! videoconvert ! videoscale add-borders=false ! video/x-raw,width=%d,height=%d' % (capture, fps, w, h)
+    if codec == 'jpeg':
+        enc = 'jpegenc name=enc quality=80'
+        parse = ''
+    else:
+        choices = {
+            'mfh264enc': 'mfh264enc name=enc low-latency=true bframes=0 gop-size=60',
+            'vah264enc': 'vah264enc name=enc b-frames=0 key-int-max=60',
+            'x264enc': 'x264enc name=enc tune=zerolatency speed-preset=ultrafast bframes=0 key-int-max=60',
+        }
+        enc = choices[encoder] + ' bitrate=%d' % max(1, bitrate // 1000)
+        raw += ',format=NV12' if encoder != 'x264enc' else ',format=I420'
+        parse = ' ! h264parse config-interval=-1 ! video/x-h264,stream-format=byte-stream,alignment=au'
+    return raw + ' ! ' + enc + parse + ' ! appsink name=out sync=false max-buffers=2 drop=false'
+
+
+# X11 keysyms work on Wayland through the RemoteDesktop portal too. The host's
+# keyboard layout handles physical keys; Unicode text is sent as Unicode keysyms.
+KEYSYMS = {'Enter': 0xff0d, 'Tab': 0xff09, 'Backspace': 0xff08, 'Escape': 0xff1b,
+           'Delete': 0xffff, 'ArrowLeft': 0xff51, 'ArrowUp': 0xff52, 'ArrowRight': 0xff53,
+           'ArrowDown': 0xff54, 'Home': 0xff50, 'End': 0xff57, 'PageUp': 0xff55,
+           'PageDown': 0xff56, 'Shift': 0xffe1, 'Control': 0xffe3, 'Alt': 0xffe9, 'Meta': 0xffeb}
+
+
+class PortalInput:
+    def __init__(self, native, source):
+        self.lib, self.source = native.lib, source
+        self.buttons, self.keys = set(), set()
+
+    def emit(self, kind, x=0, y=0, code=0, down=0):
+        if not self.lib.fc_portal_input(self.source['portal'], kind, x, y, code, down):
+            raise RuntimeError('The desktop portal refused input; check the sharing permission')
+
+    def release(self):
+        error = None
+        for values, kind in ((self.buttons, 1), (self.keys, 3)):
+            for code in list(values):
+                try:
+                    self.emit(kind, code=code, down=0)
+                    values.discard(code)
+                except RuntimeError as e:
+                    error = e
+        if error:
+            raise error
+
+    def handle(self, m):
+        t = m['t']
+        if t == 'release':
+            return self.release()
+        if t in ('m', 'wheel'):
+            x, y = (max(0, min(1, float(m.get(k, 0)))) for k in ('x', 'y'))
+            self.emit(0, x * (self.source['w'] - 1), y * (self.source['h'] - 1))
+        if t == 'm' and m.get('e') in ('up', 'down'):
+            b = {0: 0x110, 1: 0x112, 2: 0x111}.get(m.get('b', 0))
+            if b is not None:
+                down = m['e'] == 'down'
+                self.emit(1, code=b, down=down)
+                (self.buttons.add if down else self.buttons.discard)(b)
+        elif t == 'wheel':
+            self.emit(2, max(-4096, min(4096, float(m.get('dx', 0)))), max(-4096, min(4096, float(m.get('dy', 0)))))
+        elif t == 'k':
+            key = str(m.get('key', ''))
+            k = KEYSYMS.get(key) or (ord(key) if len(key) == 1 and ord(key) < 256 else
+                                     0x1000000 + ord(key) if len(key) == 1 else 0)
+            if k:
+                down = m.get('e') == 'down'
+                self.emit(3, code=k, down=down)
+                (self.keys.add if down else self.keys.discard)(k)
+        elif t == 'text':
+            for ch in str(m.get('s', ''))[:4096]:
+                k = ord(ch) if ord(ch) < 256 else 0x1000000 + ord(ch)
+                self.emit(3, code=k, down=1)
+                self.emit(3, code=k, down=0)
+
+
+class Windows:
+    """WGC source handles and SendInput. No elevation or global input hook."""
+    def __init__(self):
+        from ctypes import wintypes as W
+        self.W = W
+        self.user = C.WinDLL('user32', use_last_error=True)
+        self.dwm = C.WinDLL('dwmapi')
+        self.user.IsWindow.argtypes = [W.HWND]
+        self.user.IsWindowVisible.argtypes = [W.HWND]
+        self.user.IsIconic.argtypes = [W.HWND]
+        self.user.GetWindowTextLengthW.argtypes = [W.HWND]
+        self.user.GetWindowTextW.argtypes = [W.HWND, W.LPWSTR, C.c_int]
+        self.user.GetWindowRect.argtypes = [W.HWND, C.POINTER(W.RECT)]
+        self.user.SetForegroundWindow.argtypes = [W.HWND]
+        self.user.GetForegroundWindow.argtypes = []
+        self.user.GetForegroundWindow.restype = W.HWND
+        self.dwm.DwmGetWindowAttribute.argtypes = [W.HWND, W.DWORD, C.c_void_p, W.DWORD]
+        self.callback = C.WINFUNCTYPE(W.BOOL, W.HWND, W.LPARAM)
+        self.monitor_callback = C.WINFUNCTYPE(W.BOOL, W.HMONITOR, W.HDC, C.POINTER(W.RECT), W.LPARAM)
+        self.user.EnumWindows.argtypes = [self.callback, W.LPARAM]
+        self.user.EnumDisplayMonitors.argtypes = [W.HDC, C.c_void_p, self.monitor_callback, W.LPARAM]
+        class Mouse(C.Structure):
+            _fields_ = [('dx', W.LONG), ('dy', W.LONG), ('data', W.DWORD), ('flags', W.DWORD),
+                        ('time', W.DWORD), ('extra', C.c_size_t)]
+        class Key(C.Structure):
+            _fields_ = [('vk', W.WORD), ('scan', W.WORD), ('flags', W.DWORD), ('time', W.DWORD), ('extra', C.c_size_t)]
+        class Union(C.Union):
+            _fields_ = [('mouse', Mouse), ('key', Key)]
+        class Input(C.Structure):
+            _fields_ = [('type', W.DWORD), ('data', Union)]
+        self.Mouse, self.Key, self.Input = Mouse, Key, Input
+        self.user.SendInput.argtypes = [W.UINT, C.POINTER(Input), C.c_int]
+        self.user.SendInput.restype = W.UINT
+
+    def rect(self, hwnd):
+        r = self.W.RECT()
+        if not self.user.IsWindow(hwnd) or self.user.IsIconic(hwnd):
+            raise RuntimeError('The captured window closed or was minimized')
+        # WGC captures the visible extended frame, excluding invisible resize borders.
+        if self.dwm.DwmGetWindowAttribute(hwnd, 9, C.byref(r), C.sizeof(r)):
+            if not self.user.GetWindowRect(hwnd, C.byref(r)):
+                raise RuntimeError('Cannot locate the captured window')
+        return r.left, r.top, r.right - r.left, r.bottom - r.top
+
+    def sources(self):
+        windows, displays = [], []
+        def window(hwnd, _):
+            if not self.user.IsWindowVisible(hwnd) or self.user.IsIconic(hwnd):
+                return True
+            n = self.user.GetWindowTextLengthW(hwnd)
+            if n:
+                title = C.create_unicode_buffer(n + 1)
+                self.user.GetWindowTextW(hwnd, title, n + 1)
+                try:
+                    x, y, w, h = self.rect(hwnd)
+                    if w > 0 and h > 0:
+                        windows.append(dict(src='window:%d' % hwnd, id=hwnd, title=title.value,
+                                            app='Windows', w=w, h=h, x=x, y=y))
+                except RuntimeError:
+                    pass
+            return True
+        def monitor(handle, dc, rect, data):
+            r = rect.contents
+            displays.append(dict(src='display:%d' % handle, name='Display %d' % (len(displays) + 1),
+                                 x=r.left, y=r.top, w=r.right-r.left, h=r.bottom-r.top))
+            return True
+        self.user.EnumWindows(self.callback(window), 0)
+        self.user.EnumDisplayMonitors(None, None, self.monitor_callback(monitor), 0)
+        return windows, displays
+
+    def send(self, mouse=None, key=None):
+        inp = self.Input()
+        inp.type = 0 if mouse else 1
+        if mouse:
+            inp.data.mouse = self.Mouse(*mouse, 0, 0)
+        else:
+            inp.data.key = self.Key(*key, 0, 0)
+        if self.user.SendInput(1, C.byref(inp), C.sizeof(inp)) != 1:
+            raise RuntimeError('Windows refused input (elevated apps and the secure desktop cannot be controlled)')
+
+
+class WindowsInput:
+    def __init__(self, host, source):
+        self.host, self.source = host, source
+        self.buttons, self.keys = set(), set()
+
+    def release(self):
+        error = None
+        for button in list(self.buttons):
+            try:
+                self.host.send(mouse=(0, 0, 0, {0: 4, 1: 0x40, 2: 0x10}[button]))
+                self.buttons.discard(button)
+            except RuntimeError as e:
+                error = e
+        for vk in list(self.keys):
+            try:
+                extended = 1 if vk in (33, 34, 35, 36, 37, 38, 39, 40, 45, 46, 91, 92, 163, 165) else 0
+                self.host.send(key=(vk, 0, 2 | extended))
+                self.keys.discard(vk)
+            except RuntimeError as e:
+                error = e
+        if error:
+            raise error
+
+    def focus(self):
+        if not self.source['src'].startswith('window:'):
+            return
+        hwnd = int(self.source['src'].split(':')[1])
+        user = self.host.user
+        if user.GetForegroundWindow() != hwnd and not user.SetForegroundWindow(hwnd):
+            raise RuntimeError('Windows could not focus this window. Bring it to the front on your PC, then press Stop and Show again.')
+        if user.GetForegroundWindow() != hwnd:
+            raise RuntimeError('The selected window is not in front. Reopen the view after bringing it to the front on your PC.')
+
+    def handle(self, m):
+        t, u = m['t'], self.host.user
+        if t == 'release':
+            return self.release()
+        if t in ('m', 'wheel'):
+            source = self.source
+            if source['src'].startswith('window:'):
+                hwnd = int(source['src'].split(':')[1])
+                x, y, w, h = self.host.rect(hwnd)
+                if m.get('e') == 'down' or t == 'wheel':
+                    self.focus()
+            else:
+                x, y, w, h = (source[k] for k in ('x', 'y', 'w', 'h'))
+            x += max(0, min(1, float(m.get('x', 0)))) * (w - 1)
+            y += max(0, min(1, float(m.get('y', 0)))) * (h - 1)
+            left, top, width, height = (u.GetSystemMetrics(i) for i in (76, 77, 78, 79))
+            self.host.send(mouse=(round((x-left)*65535/max(1,width-1)), round((y-top)*65535/max(1,height-1)), 0, 0xc001))
+        if t == 'm' and m.get('e') in ('up', 'down'):
+            b = m.get('b', 0)
+            if b in (0, 1, 2):
+                down = m['e'] == 'down'
+                self.host.send(mouse=(0, 0, 0, {0: 2, 1: 0x20, 2: 8}[b] * (1 if down else 2)))
+                (self.buttons.add if down else self.buttons.discard)(b)
+        elif t == 'wheel':
+            for name, flag, direction in (('dy', 0x800, -1), ('dx', 0x1000, 1)):
+                delta = int(max(-4096, min(4096, float(m.get(name, 0))))) * direction
+                if delta:
+                    self.host.send(mouse=(0, 0, delta & 0xffffffff, flag))
+        elif t == 'k':
+            code, down = str(m.get('code', '')), m.get('e') == 'down'
+            if down:
+                self.focus()
+            special = {'Enter': 13, 'Escape': 27, 'Tab': 9, 'Backspace': 8, 'Space': 32,
+                       'ArrowLeft': 37, 'ArrowUp': 38, 'ArrowRight': 39, 'ArrowDown': 40,
+                       'Delete': 46, 'Home': 36, 'End': 35, 'PageUp': 33, 'PageDown': 34,
+                       'ShiftLeft': 160, 'ShiftRight': 161, 'ControlLeft': 162, 'ControlRight': 163,
+                       'AltLeft': 164, 'AltRight': 165, 'MetaLeft': 91, 'MetaRight': 92}
+            vk = special.get(code, 0)
+            if re.fullmatch(r'Key[A-Z]', code) or re.fullmatch(r'Digit[0-9]', code):
+                vk = ord(code[-1])
+            if vk:
+                extended = 1 if vk in (33, 34, 35, 36, 37, 38, 39, 40, 45, 46, 91, 92, 163, 165) else 0
+                self.host.send(key=(vk, 0, extended | (0 if down else 2)))
+                (self.keys.add if down else self.keys.discard)(vk)
+            elif down and len(str(m.get('key', ''))) == 1:
+                self.handle({'t': 'text', 's': m['key']})
+        elif t == 'text':
+            self.focus()
+            raw = str(m.get('s', ''))[:4096].encode('utf-16-le')
+            for i in range(0, len(raw), 2):
+                unit = int.from_bytes(raw[i:i+2], 'little')
+                self.host.send(key=(0, unit, 4))
+                self.host.send(key=(0, unit, 6))

ui/frame_pcview.py

@@ -0,0 +1,130 @@
+"""PC in the headset (Experimental, Windows only), behind the existing MacView
+tunnel/panel controller.
+
+The public /api/macview name and viewer URL are the Mac feature's. Only helper
+launch, platform availability and source validation are different. No second
+viewer, SSH supervisor or benchmark launcher.
+
+It is off until the person turns it on in Tools: until then nothing starts,
+no native library is loaded and no window is listed. The Linux adapter from
+PR #38 is in the tree but never offered (host_view only picks this on Windows).
+"""
+import os
+import sys
+import subprocess
+from frame_macview import MacView, MacViewError, ROOT
+from frame_pc_capture import LIBRARY, NATIVE
+
+
+def prepend(env, name, path):
+    """An empty entry means the current directory to the loader; never add one."""
+    rest = env.get(name, '')
+    env[name] = str(path) + (os.pathsep + rest if rest else '')
+
+
+OFF = 'Off. Turn it on to list your windows and screens.'
+
+
+class PCView(MacView):
+    viewer_profile = 'pc-view'
+    host = 'windows' if sys.platform == 'win32' else 'linux'
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.prefer_usb = False  # Mac networksetup probe is platform-specific
+        self.enabled = False
+
+    def unavailable(self):
+        if sys.platform != 'win32':
+            return 'PC in the headset is only available on Windows for now.'
+        if not self.enabled:
+            return OFF
+        if not LIBRARY.is_file():
+            return 'The PC streaming libraries are missing from this build. See docs/pc-in-headset.md.'
+        return None
+
+    def state(self):
+        result = super().state()
+        result.update(host=self.host, experimental=True, enabled=self.enabled)
+        return result
+
+    def set_enabled(self, on):
+        """Turning it off ends every stream and the helper; nothing restarts
+        it until it's turned on again (ensure_agent asks unavailable())."""
+        if on:
+            with self.lock:
+                self.enabled = True
+            return self.state()
+        try:
+            self.stop()  # while still enabled, so the viewers on the Frame close too
+        except MacViewError:
+            pass
+        with self.lock:
+            self.enabled = False
+            self._drop_tunnel()
+            agent, self.agent = self.agent, None
+        if agent and agent.poll() is None:
+            # EOF gives the host a chance to release held input, including on
+            # Windows where terminate is uncatchable.
+            if agent.stdin:
+                agent.stdin.close()
+            try:
+                agent.wait(10)
+            except subprocess.TimeoutExpired:
+                agent.kill()
+                agent.wait(5)
+        return self.state()
+
+    def build(self):
+        pass  # native libraries are built and bundled with the app
+
+    def agent_command(self):
+        return [sys.executable, str(ROOT / 'ui' / 'frame_pc_agent.py')]
+
+    def agent_environment(self):
+        env = super().agent_environment()
+        env['GST_PLUGIN_PATH_1_0'] = str(NATIVE / 'lib' / 'gstreamer-1.0')
+        env['GST_PLUGIN_SYSTEM_PATH_1_0'] = ''
+        cache = os.path.join(os.path.expanduser('~'), '.cache', 'frame-control')
+        os.makedirs(cache, exist_ok=True)
+        env['GST_REGISTRY_1_0'] = os.path.join(cache, 'gstreamer-registry.bin')
+        env['GST_REGISTRY_FORK'] = 'no'
+        if sys.platform == 'win32':
+            prepend(env, 'PATH', NATIVE / 'bin')
+        else:
+            prepend(env, 'LD_LIBRARY_PATH', NATIVE / 'lib')
+            env['PIPEWIRE_MODULE_DIR'] = str(NATIVE / 'lib' / 'pipewire-0.3')
+            env['SPA_PLUGIN_DIR'] = str(NATIVE / 'lib' / 'spa-0.2')
+            env['PIPEWIRE_CONFIG_DIR'] = str(NATIVE / 'share' / 'pipewire')
+            env['PIPEWIRE_CONFIG_NAME'] = 'client.conf'
+        return env
+
+    def shutdown(self):
+        self.closing = True
+        try:
+            self.stop()
+        except MacViewError:
+            pass
+        if self.tunnel and self.tunnel.poll() is None:
+            self.tunnel.terminate()
+        if self.agent and self.agent.poll() is None:
+            # EOF gives the host a chance to release held input and portal
+            # sessions, including on Windows where terminate is uncatchable.
+            if self.agent.stdin:
+                self.agent.stdin.close()
+            try:
+                self.agent.wait(10)
+            except subprocess.TimeoutExpired:
+                self.agent.kill()
+                self.agent.wait(5)
+
+    def _show(self, src, quality, width, height):
+        if src.startswith('separate:'):
+            raise MacViewError('Separate virtual displays are a Mac-only feature. Choose a window or screen.')
+        return super()._show(src, quality, width, height)
+
+
+def host_view(*args, **kwargs):
+    """Windows gets the PC host; everywhere else keeps the Mac view, which
+    reports itself unavailable off macOS."""
+    return (PCView if sys.platform == 'win32' else MacView)(*args, **kwargs)

ui/frame_stream_stats.py

@@ -0,0 +1,88 @@
+"""The desktop stream's timing records, in the Mac viewer/bench schema.
+
+Times are host monotonic microseconds. Zero means unknown, never a fabricated
+capture/display timestamp. Storage is bounded to the same 4096/512 records as
+Stats.swift. The existing macview-bench.py grades these records unchanged.
+"""
+from collections import OrderedDict
+import threading
+
+
+def distribution(values):
+    values = sorted(v for v in values if v is not None)
+    if not values:
+        return {}
+    return {key: round(values[min(len(values)-1, int((len(values)-1)*p + .5))], 1)
+            for key, p in (('p50', .5), ('p95', .95))}
+
+
+class Stats:
+    def __init__(self, now):
+        self.now, self.lock = now, threading.RLock()
+        self.frames, self.inputs = OrderedDict(), OrderedDict()
+        self.captured = self.skipped = self.dropped = 0
+        self.rtt, self.decoder, self.synced = 0, '', False
+        self.sequence = 0
+
+    def add(self, **values):
+        with self.lock:
+            self.sequence = (self.sequence + 1) & 0xffffffff
+            record = dict.fromkeys(('s', 'k', 'b', 'w', 'h', 'cap', 'arr', 'e0', 'e1', 'snd',
+                                    'wire', 'rx', 'dec', 'drw', 'vs', 'echo', 'tier', 'br'), 0)
+            record.update(values, s=self.sequence)
+            self.frames[self.sequence] = record
+            while len(self.frames) > 4096:
+                self.frames.popitem(last=False)
+            for event in self.inputs.values():
+                if not event['frame'] and event['inj'] <= record['cap']:
+                    event.update(frame=self.sequence, cap=record['cap'])
+                    record['echo'] = event['id']
+            return record
+
+    def report(self, message):
+        with self.lock:
+            if message['t'] == 'rx':
+                frame = self.frames.get(message.get('s'))
+                if frame and isinstance(message.get('r'), (int, float)):
+                    frame['rx'] = int(message['r'])
+            elif message['t'] == 'fd':
+                for item in message.get('f', [])[:4096]:
+                    if isinstance(item, list) and len(item) >= 4:
+                        frame = self.frames.get(item[0])
+                        if frame:
+                            for name, val in zip(('dec', 'drw', 'vs'), item[1:4]):
+                                if isinstance(val, (int, float)):
+                                    frame[name] = int(val)
+                self.dropped += max(0, int(message.get('drop', 0)))
+            elif message['t'] == 'clock':
+                self.rtt = float(message.get('rtt', 0))
+                self.decoder = str(message.get('dec', ''))[:1024]
+                self.synced = True
+
+    def input(self, m):
+        if not isinstance(m.get('i'), int) or not m['i']:
+            return
+        with self.lock:
+            self.inputs[m['i']] = dict(id=m['i'], kind=m['t'], tv=m.get('tv') or 0,
+                                       inj=self.now(), frame=0, cap=0)
+            while len(self.inputs) > 512:
+                self.inputs.popitem(last=False)
+
+    def summary(self):
+        with self.lock:
+            now = self.now()
+            frames = [f for f in self.frames.values() if f['cap'] >= now-2000000]
+            out = dict(captured=self.captured, skipped=self.skipped, dropped=self.dropped,
+                       rtt=self.rtt, decoder=self.decoder, synced=self.synced,
+                       fps=sum(f['vs'] > 0 for f in frames)/2, sentFps=len(frames)/2,
+                       mbps=round(sum(f['b'] for f in frames)*4/1e6, 2))
+            for key, start, end in (('capture', 'cap', 'arr'), ('queue', 'arr', 'e0'),
+                                    ('encode', 'e0', 'e1'), ('network', 'e1', 'rx'),
+                                    ('decode', 'rx', 'dec'), ('draw', 'dec', 'drw'), ('total', 'cap', 'drw')):
+                out[key] = distribution([(f[end]-f[start])/1000 for f in frames if f[start] and f[end]])
+            return out
+
+    def snapshot(self, since=0, settle=1500000):
+        with self.lock:
+            return dict(frames=[dict(f) for f in self.frames.values() if f['s'] > since and f['cap'] <= self.now()-settle],
+                        inputs=[dict(i) for i in self.inputs.values()], captured=self.captured, summary=self.summary())

ui/index.html

@@ -1420,7 +1420,7 @@
 
   <div class="page" data-page="tools">
 <div class="workspace-heading"><div><a href="#tools" id="toolBack" class="workspace-link" hidden>← All tools</a><h1 id="toolTitle">Tools</h1><p id="toolSubtitle">Choose a task for your Frame.</p></div></div>
-<div id="toolDirectory"><section class="tool-group"><h2>Content & files</h2><div class="quick-routes"><a href="#transfer"><span>Send to Frame</span><small>Add files, APKs or your own games</small></a><a href="#media"><span>Media player</span><small>Play your own videos and media</small></a><a href="#linuxApps"><span>Linux apps</span><small>Install and manage desktop apps</small></a></div></section><section class="tool-group"><h2>Play & control</h2><div class="quick-routes"><a href="#capture"><span>Capture & Live</span><small>See and control the headset view</small></a><a href="#pad" title="Type on the headset (T)"><span>Type on the headset</span><small>Keyboard, trackpad and clipboard</small></a><a href="#panels"><span>Panel switcher</span><small>Bring an open panel into view</small></a><a href="#vrTools"><span>VR tools</span><small>Performance HUD and VR utilities</small></a><a href="#comfort"><span>Family & comfort</span><small>Session reminders and breaks</small></a><a href="#macview" id="macToolLink" hidden><span>Mac in the headset</span><small>Share Mac windows and displays</small></a></div></section><section class="tool-group"><h2>Your Frame</h2><a class="workspace-link" href="#settings">Connection, display &amp; preferences →</a></section><section class="tool-group"><h2>Assistant</h2><a class="workspace-link" href="/assistant">Open assistant &amp; AI agents →</a><p class="sub">Use your own model endpoint or review a proposed MCP action.</p></section></div>
+<div id="toolDirectory"><section class="tool-group"><h2>Content & files</h2><div class="quick-routes"><a href="#transfer"><span>Send to Frame</span><small>Add files, APKs or your own games</small></a><a href="#media"><span>Media player</span><small>Play your own videos and media</small></a><a href="#linuxApps"><span>Linux apps</span><small>Install and manage desktop apps</small></a></div></section><section class="tool-group"><h2>Play & control</h2><div class="quick-routes"><a href="#capture"><span>Capture & Live</span><small>See and control the headset view</small></a><a href="#pad" title="Type on the headset (T)"><span>Type on the headset</span><small>Keyboard, trackpad and clipboard</small></a><a href="#panels"><span>Panel switcher</span><small>Bring an open panel into view</small></a><a href="#vrTools"><span>VR tools</span><small>Performance HUD and VR utilities</small></a><a href="#comfort"><span>Family & comfort</span><small>Session reminders and breaks</small></a><a href="#macview" id="macToolLink" hidden><span>Mac in the headset</span><small>Share Mac windows and displays</small></a><a href="#macview" id="pcToolLink" hidden><span>PC in the headset</span><small>Experimental: share this PC's windows and screens</small></a></div></section><section class="tool-group"><h2>Your Frame</h2><div class="quick-routes"><a href="#backup" id="backupToolLink"><span>Backup &amp; recovery</span><small>Save games and settings, restore after a reset</small></a></div><a class="workspace-link" href="#settings">Connection, display &amp; preferences →</a></section><section class="tool-group"><h2>Assistant</h2><a class="workspace-link" href="/assistant">Open assistant &amp; AI agents →</a><p class="sub">Use your own model endpoint or review a proposed MCP action.</p></section></div>
   <div class="grid-3" id="toolWorkspace">
 <section class="panel" id="vrTools">
     <div class="shelf-head"><h2>VR comfort and performance</h2><span class="spacer"></span><span class="sub" id="vrUpdated">Waiting for the Frame</span></div>
@@ -1667,9 +1667,55 @@
         Saved spatial layouts are not available yet.</div>
     </section>
 
+    <section class="panel" id="backup" hidden>
+      <div class="shelf-head"><h2>Back up the Frame</h2><span class="spacer"></span>
+        <button class="small" id="backupFolder">Open backups folder</button></div>
+      <p class="sub">Copies game saves, settings and Android app data from the headset to a dated folder on this computer.
+        It only reads the headset. Games themselves aren't copied: reinstall them from Steam.</p>
+      <div class="chips" id="backupKinds">
+        <label><input type="checkbox" value="saves" checked> Game saves</label>
+        <label><input type="checkbox" value="settings" checked> Steam and desktop settings</label>
+        <label><input type="checkbox" value="android" checked> Android app data</label>
+      </div>
+      <div class="row" style="margin-top:12px"><button class="small" id="backupPreview">See what's included</button>
+        <button class="small action" id="backupStart">Back up now</button></div>
+      <div class="sub" id="backupProgress" role="status" aria-live="polite"></div>
+      <div class="list" id="backupSummary"></div>
+      <div class="hint">Never copied: Steam sign-in files (steam.token, config.vdf, loginusers.vdf), SSH keys,
+        keyrings and other passwords. Backups aren't encrypted, and game folders can hold launcher logins, so keep them private.
+        Close Android apps first: open ones are skipped.</div>
+
+      <div class="shelf-head" style="margin-top:20px"><h2>Restore</h2><span class="spacer"></span>
+        <button class="small" id="backupRefresh">Refresh</button></div>
+      <div class="list" id="backupList"><div class="sub">Open this tool to see your backups.</div></div>
+      <div id="restorePlan"></div>
+      <div class="hint">After a factory reset, sign in to Steam, reinstall your games and start each once, and reinstall
+        your Android apps. Then restore. Parts that can't go back yet are skipped, not failed. Files a restore replaces are
+        kept on the headset in ~/.local/share/frame-control/restore-previous.</div>
+
+      <div class="shelf-head" style="margin-top:20px"><h2>Stuck in Desktop Mode?</h2><span class="spacer"></span>
+        <button class="small" id="sessionCheck">Check</button></div>
+      <div class="sub" id="sessionState">Check which mode the headset is in.</div>
+      <div class="row" style="margin-top:12px"><button class="small" id="sessionGame" disabled>Return to Game Mode</button></div>
+      <div class="hint">Uses the same switch as Valve's developer tools (<code>steamos-session-select gamescope</code>).
+        It closes the desktop and anything open in it. If the headset can't be reached, hold Power for 10 seconds to
+        restart it; <a href="https://github.com/saphid/frame-control/blob/main/docs/backup-and-recovery.md#stuck-in-desktop-mode" target="_blank">more ways back</a>.</div>
+    </section>
+
     <section class="panel" id="macview" hidden>
-      <div class="shelf-head"><h2>Mac in the headset</h2><span class="count" id="mvCount"></span><span class="spacer"></span>
+      <div class="shelf-head"><h2 id="mvTitle">Mac in the headset</h2><span class="tag" id="mvTag" hidden>Experimental</span><span class="count" id="mvCount"></span><span class="spacer"></span>
         <button class="small" id="mvRefresh">Refresh</button></div>
+      <div id="mvPc" hidden>
+        <p class="hint" style="color:var(--warn)">Experimental. Shows this PC's windows and screens as panels in the
+          headset, with laser and keyboard input. It builds and passes its tests on Windows in CI, but hasn't been tried on a real
+          Windows desktop or with a headset yet: capture, hardware encoding and laser clicks may not work. Clicks and keys
+          can't reach administrator apps or the sign-in screen.
+          <a href="https://github.com/saphid/frame-control/blob/main/docs/pc-in-headset.md" target="_blank" rel="noopener noreferrer">What's verified</a></p>
+        <label class="mv-opt"><input type="checkbox" id="mvPcOn"> Turn on PC in the headset
+          <span class="sub">off by default; nothing runs and no windows are listed until it's on</span></label>
+        <div class="sub" id="mvPcState" role="status" aria-live="polite" hidden></div>
+      </div>
+      <div id="mvMain">
       <label class="mv-opt"><input type="checkbox" id="mvSeparate" checked> Give each window its own display
         <span class="sub">its menus and sheets come along, nothing covers it, and it goes back when you stop</span></label>
       <div class="row" style="margin:0 0 12px"><label for="mvQuality">Picture quality</label>
@@ -1686,7 +1732,8 @@
         <button class="small danger" data-mv="stopall">Stop all</button>
       </div>
       <div class="hint">Each window or screen becomes its own panel in the headset. Place it with the SteamVR dashboard
-        (Float in World, Move, Size). Point and click with the laser, scroll with the thumbstick, and type on the Mac's keyboard.</div>
+        (Float in World, Move, Size). Point and click with the laser, scroll with the thumbstick, and type on your computer's keyboard.</div>
+      </div>
     </section>
 
     <section class="panel" id="privacy">
@@ -5378,8 +5425,140 @@ $("panelList").onclick = e => {
   act("Show panel", () => api("/api/panels", {action: "focus", key: b.dataset.panel}), b);
 };
 
+// ---- Backup and recovery kit (ui/frame_backup.py) ----
+const BACKUP_KIND = {saves: "Game saves", settings: "Settings", android: "Android app data"};
+function sizeText(n) {
+  if (n == null) return "";
+  for (const unit of ["bytes", "KB", "MB", "GB"]) {
+    if (n < 1000 || unit === "GB") return unit === "bytes" ? `${n} bytes` : `${n.toFixed(1)} ${unit}`;
+    n /= 1000;
+  }
+}
+const backupKinds = () => [...$("backupKinds").querySelectorAll("input:checked")].map(i => i.value);
+let backupSeq = 0, backupBusy = false;
+async function loadBackups() {
+  const seq = ++backupSeq;
+  try {
+    const r = await api("/api/backup", {action: "list"});
+    if (seq !== backupSeq) return;
+    $("backupList").innerHTML = r.backups.length ? r.backups.map(b => `<div class="item"><div class="grow">
+        <div class="t">${esc(b.name)}</div><div class="s">${b.error ? esc(b.error) :
+        esc([b.headset, b.build && `SteamOS build ${b.build}`, `${b.parts} part${b.parts === 1 ? "" : "s"}`, sizeText(b.bytes)].filter(Boolean).join(" · "))}</div></div>
+        ${b.error ? "" : `<button class="small" data-backup-plan="${esc(b.name)}">Restore…</button>`}</div>`).join("")
+      : `<div class="sub">No backups in ${esc(r.folder)} yet.</div>`;
+  } catch (e) { if (seq === backupSeq) failed($("backupList"), e); }
+}
+function backupPartRow(p, restore) {
+  const detail = restore
+    ? (p.status === "ok" ? [p.replace ? `replaces ${p.replace} file${p.replace === 1 ? "" : "s"}` : "", p.new ? `${p.new} new` : "",
+                            p.held && p.held.reference ? `${p.held.reference} kept for reference` : ""].filter(Boolean).join(", ") || "ready"
+                         : p.reason || p.status)
+    : [`${p.files} file${p.files === 1 ? "" : "s"}`, sizeText(p.bytes), p.skipped && p.skipped.length ? `${p.skipped.length} too big, skipped` : ""].filter(Boolean).join(" · ");
+  const box = restore ? `<input type="checkbox" data-restore-part="${esc(p.id)}" ${p.status === "ok" ? "checked" : "disabled"} aria-label="Restore ${esc(p.label)}"> ` : "";
+  return `<div class="item"><div class="grow"><div class="t">${box}${esc(p.label)}</div><div class="s">${esc(detail)}</div></div></div>`;
+}
+$("backupPreview").onclick = e => act("Check what a backup includes", async () => {
+  const r = await api("/api/backup", {action: "preview"}), kinds = backupKinds();
+  const rows = r.parts.filter(p => kinds.includes(p.kind)).map(p => backupPartRow(p, false));
+  if (kinds.includes("android")) rows.push(...r.android.map(a => `<div class="item"><div class="grow"><div class="t">${esc(a.label)} (Android app data)</div>
+      <div class="s">${a.running ? "Open now: close it or it's skipped" : "Saved while closed"}</div></div></div>`));
+  if (r.android_error && kinds.includes("android")) rows.push(`<div class="sub">Android apps couldn't be listed: ${esc(r.android_error)}</div>`);
+  $("backupSummary").innerHTML = (rows.join("") || '<div class="sub">Nothing to back up for that choice.</div>') +
+    `<details><summary>Never copied</summary><ul>${r.excluded.map(x => `<li>${esc(x)}</li>`).join("")}</ul></details>`;
+  return {message: `SteamOS build ${r.build || "unknown"}: ${rows.length} part${rows.length === 1 ? "" : "s"} to back up`};
+}, e.currentTarget);
+// Like runJob, without counting as an install in the header.
+async function backupJob(label, start) {
+  log(label + "…");
+  try {
+    const { job } = await start();
+    for (let misses = 0; ;) {
+      await new Promise(ok => setTimeout(ok, 1500));
+      let j;
+      try { j = await api(`/api/job?id=${encodeURIComponent(job)}`); misses = 0; }
+      catch (e) { if (++misses >= 20 || /no such job/.test(e.message)) throw e; continue; }
+      backupProgress(j);
+      if (!j.done) continue;
+      if (j.error) throw new Error(j.error);
+      log(j.message, "ok"); toast(j.message);
+      return j.result || {};
+    }
+  } catch (e) {
+    log(`${label} failed: ${e.message}`, "e"); toast(`${label} failed: ${e.message}`, true);
+  }
+}
+function backupProgress(j) {
+  $("backupProgress").textContent = j.done ? "" : `${j.stage || "Starting"}${j.percent != null ? ` · ${Math.round(j.percent)}%` : ""}`;
+}
+$("backupStart").onclick = async e => {
+  const kinds = backupKinds();
+  if (!kinds.length) return toast("Choose something to back up", true);
+  if (backupBusy) return;
+  backupBusy = true; e.currentTarget.disabled = true;
+  try {
+    const r = await backupJob("Back up the Frame", () => api("/api/backup", {action: "backup", kinds}));
+    if (r) {
+      $("backupSummary").innerHTML = `<div class="sub">${esc(r.message)}</div>` + (r.skipped || []).map(s =>
+        `<div class="item"><div class="grow"><div class="t">${esc(s.label || s.id)}${s.path ? `: ${esc(s.path)}` : ""}</div>
+         <div class="s">Skipped: ${esc(s.reason)}</div></div></div>`).join("");
+      loadBackups();
+    }
+  } finally { backupBusy = false; $("backupStart").disabled = false; $("backupProgress").textContent = ""; }
+};
+$("backupFolder").onclick = e => act("Open backups folder", () => api("/api/backup", {action: "open"}), e.currentTarget);
+$("backupRefresh").onclick = loadBackups;
+let restoreName = null;
+$("backupList").onclick = async e => {
+  const b = e.target.closest("[data-backup-plan]"); if (!b) return;
+  restoreName = b.dataset.backupPlan;
+  $("restorePlan").innerHTML = '<div class="sub">Checking what can go back…</div>';
+  try {
+    const r = await api("/api/backup", {action: "plan", name: restoreName});
+    if (r.name !== restoreName) return;
+    $("restorePlan").innerHTML = `<h3>Restore ${esc(r.name)}</h3>` + r.parts.map(p => backupPartRow(p, true)).join("") +
+      `<div class="row" style="margin-top:12px"><button class="small danger" id="restoreStart">Restore selected</button>
+       <button class="small" data-backup-open="${esc(r.name)}">Show files</button></div>`;
+    $("restorePlan").plan = r;
+  } catch (err) { failed($("restorePlan"), err); }
+};
+$("restorePlan").onclick = async e => {
+  const open = e.target.closest("[data-backup-open]");
+  if (open) return act("Show backup files", () => api("/api/backup", {action: "open", name: open.dataset.backupOpen}), open);
+  if (!e.target.closest("#restoreStart") || backupBusy) return;
+  const plan = $("restorePlan").plan;
+  const parts = [...$("restorePlan").querySelectorAll("[data-restore-part]:checked")].map(i => i.dataset.restorePart);
+  if (!plan || !parts.length) return toast("Choose something to restore", true);
+  const chosen = plan.parts.filter(p => parts.includes(p.id));
+  const replacing = chosen.reduce((n, p) => n + (p.replace || 0), 0);
+  if (!confirm(`Restore ${chosen.length} part${chosen.length === 1 ? "" : "s"} from ${plan.name}?\n\n` +
+               `${replacing ? `This replaces ${replacing} file${replacing === 1 ? "" : "s"} or app data folder${replacing === 1 ? "" : "s"} on the headset. ` : ""}` +
+               "Replaced files are kept on the headset. Close the games and apps you're restoring first.")) return;
+  backupBusy = true;
+  try {
+    const r = await backupJob("Restore from backup", () => api("/api/backup", {action: "restore", name: plan.name, parts, confirm: true}));
+    if (r) $("restorePlan").innerHTML = `<div class="sub">${esc(r.message)}</div>` + (r.skipped || []).map(s =>
+      `<div class="item"><div class="grow"><div class="t">${esc(s.label || s.id)}</div><div class="s">Skipped: ${esc(s.reason)}</div></div></div>`).join("");
+  } finally { backupBusy = false; $("backupProgress").textContent = ""; }
+};
+const SESSION_TEXT = {game: "Game Mode: the headset is running normally. A desktop you see is a panel; close it from the Steam dashboard.",
+  desktop: "Desktop Mode: the headset started the full desktop instead of Game Mode.",
+  unknown: "Couldn't tell which mode the headset is in."};
+$("sessionCheck").onclick = async e => {
+  e.currentTarget.disabled = true;
+  try {
+    const s = await api("/api/backup", {action: "session"});
+    $("sessionState").textContent = SESSION_TEXT[s.mode] + (s.selector ? "" : " This SteamOS build has no session switch command; use the manual steps.");
+    $("sessionGame").disabled = s.mode !== "desktop" || !s.selector;
+  } catch (err) { failed($("sessionState"), err); }
+  finally { $("sessionCheck").disabled = false; }
+};
+$("sessionGame").onclick = e => {
+  if (!confirm("Return the headset to Game Mode?\n\nThis closes the desktop and any apps open in it, then starts Steam's Game Mode.")) return;
+  act("Return to Game Mode", () => api("/api/backup", {action: "gamemode", confirm: true}), e.currentTarget);
+};
+
 // ---- Mac in the headset: windows and displays as panels (ui/frame_macview.py) ----
-let mvSeq = 0, mvTimer = 0;
+let mvSeq = 0, mvTimer = 0, mvPcAsked = false;
 // streaming: the src it's shown as (a window may be "separate:<id>"), or "".
 // How a live stream is doing: frames shown, Mac-to-headset delay, bitrate, and
 // whether the network made it step down (fewer frames, then fewer pixels).
@@ -5405,9 +5584,27 @@ async function loadMacView(restart) {
   try { s = await api("/api/macview" + (restart ? "?restart=1" : "")); } catch (e) { err = e; }
   if (seq !== mvSeq || location.hash !== "#macview") return;
   const box = $("macview");
-  if (err) { box.hidden = false; return failed($("mvWindows"), err); }
-  if (!s.available) { box.hidden = true; return; }
+  if (err) { box.hidden = $("mvMain").hidden = false; return failed($("mvWindows"), err); }
+  // PC in the headset (Windows, Experimental) is off until turned on here.
+  const pc = !!s.host && s.host !== "mac";
+  $("mvTitle").textContent = pc ? "PC in the headset" : "Mac in the headset";
+  $("mvTag").hidden = $("mvPc").hidden = !pc;
+  $("mvPcOn").checked = !!s.enabled;
+  if (pc && !s.enabled && clientPreferences.get("pcView") === "1" && !restart && !mvPcAsked) {
+    mvPcAsked = true;  // once per page: a failure to start shouldn't loop
+    return mvPcEnable(true, true);
+  }
+  if (!s.available) {
+    box.hidden = !pc;
+    $("mvMain").hidden = true;
+    $("mvCount").textContent = "";
+    if (pc) { $("mvPcState").textContent = s.reason || ""; $("mvPcState").hidden = !s.reason; }
+    return;
+  }
   box.hidden = false;
+  $("mvMain").hidden = false;
+  $("mvPcState").hidden = true;
+  $("mvSeparate").closest("label").hidden = pc;  // separate virtual displays are a Mac feature
   const live = new Set((s.streams || []).map(x => x.src));
   const byStream = src => (s.streams || []).find(x => x.src === src);
   $("mvCount").textContent = live.size ? `${live.size} showing${s.route === "usb" ? " · over USB-C" : ""}` : "";
@@ -5417,6 +5614,7 @@ async function loadMacView(restart) {
   $("mvPerm").hidden = !perm.length;
   $("mvPerm").innerHTML = perm.join(" ") + `<div class="row"><button class="small action" data-mv="perm">Allow…</button>
     <span class="sub">Then press Refresh. macOS may ask you to reopen Frame Control.</span></div>`;
+  if (pc) $("mvPerm").hidden = true;  // Windows asks for no permission; elevated apps just refuse input
   const liveAs = src => live.has(src) ? src : src.startsWith("window:") && live.has("separate:" + src.slice(7)) ? "separate:" + src.slice(7) : "";
   $("mvDisplays").innerHTML = (s.displays || []).map(d =>
     mvRow(d.src, `Whole screen: ${d.name}`, `${d.w}×${d.h}${d.main ? " · main display" : ""}`, d.w, d.h, liveAs(d.src), byStream(liveAs(d.src)))).join("");
@@ -5424,16 +5622,26 @@ async function loadMacView(restart) {
   $("mvWinCount").textContent = wins.length ? `${wins.length}` : "";
   $("mvWindows").innerHTML = !s.screen ? `<div class="sub">Windows appear here once Screen Recording is allowed.</div>`
     : wins.length ? wins.map(w => mvRow(w.src, w.title || w.app, `${w.title ? w.app + " · " : ""}${w.w}×${w.h}`, w.w, w.h, liveAs(w.src), byStream(liveAs(w.src)))).join("")
-    : `<div class="sub">No windows open on this Mac's current desktop.</div>`;
+    : `<div class="sub">No windows open on this ${pc ? "PC" : "Mac's current desktop"}.</div>`;
   // Keep the numbers fresh while something is in the headset and the card is on screen.
   clearTimeout(mvTimer);
   const tick = () => { mvTimer = document.hidden || !box.offsetParent ? setTimeout(tick, 3000) : (loadMacView(), 0); };
   if (live.size) mvTimer = setTimeout(tick, 3000);
 }
 $("mvRefresh").onclick = () => loadMacView(true);
+// The choice is remembered on this computer; the server starts with it off.
+async function mvPcEnable(on, quiet) {
+  if (!quiet) clientPreferences.set("pcView", on ? "1" : "0");
+  const turn = () => api("/api/macview", { action: "enable", on });
+  if (quiet) { try { await turn(); } catch {} }
+  else await act(on ? "Turn on PC in the headset" : "Turn off PC in the headset", async () =>
+    ({ ...await turn(), message: on ? "PC in the headset is on." : "PC in the headset is off. Nothing is shared." }), $("mvPcOn"));
+  loadMacView();
+}
+$("mvPcOn").onchange = e => mvPcEnable(e.target.checked);
 // ---- client preferences: native storage survives changing localhost origins ----
 const clientPreferences = (() => {
-  const keys = ['mvSeparate', 'padUsed'], values = {}, changed = new Set();
+  const keys = ['mvSeparate', 'padUsed', 'pcView'], values = {}, changed = new Set();
   const valid = value => value === '0' || value === '1';
   const remember = (key, value) => {
     values[key] = value;
@@ -5470,7 +5678,7 @@ $("macview").onclick = async e => {
   const b = e.target.closest("[data-mv]"); if (!b) return;
   const src = b.dataset.src;
   if (b.dataset.mv === "show") {
-    const as = $("mvSeparate").checked && src.startsWith("window:") ? "separate:" + src.slice(7) : src;
+    const as = !$("mvSeparate").closest("label").hidden && $("mvSeparate").checked && src.startsWith("window:") ? "separate:" + src.slice(7) : src;
     await act(`Show ${b.dataset.title} in the headset`, async () => {
       const r = await api("/api/macview", { action: "show", src: as, quality: $("mvQuality").value,
                                             w: +b.dataset.w || undefined, h: +b.dataset.h || undefined });
@@ -5491,10 +5699,10 @@ const PAGES = ["apps", "games", "tools", "settings"];
 const SECONDARY_PAGES = ["home", "capture", "devices", "control"];
 const SECTION_PAGE = {library:"games", discover:"apps", android:"apps", view:"capture", shots:"capture", device:"home",
   vrTools:"tools", comfort:"tools", assistant:"tools", pad:"tools", sideloaded:"games", getgames:"games", steamStore:"games", androidLibrary:"apps", appStore:"apps", linuxApps:"apps",
-  display:"settings", androidSettings:"settings", transfer:"tools", media:"tools", artworkSettings:"settings", autoSync:"settings", power:"settings", macview:"tools", privacy:"settings", panels:"tools"};
+  display:"settings", androidSettings:"settings", transfer:"tools", media:"tools", artworkSettings:"settings", autoSync:"settings", power:"settings", macview:"tools", privacy:"settings", panels:"tools", backup:"tools"};
 const TOOL_TITLES = {transfer:"Send to Frame", media:"Media player", artworkSettings:"Library artwork", autoSync:"Copy to this computer",
   pad:"Type on the headset", panels:"Panel switcher", vrTools:"VR tools", comfort:"Family & comfort", androidSettings:"App display & reports",
-  power:"Remote & power", macview:"Mac in the headset", privacy:"Privacy & updates"};
+  power:"Remote & power", macview:"Mac in the headset", privacy:"Privacy & updates", backup:"Backup & recovery"};
 const workspace = {source:"all", scope:"installed", apps:"installed", scroll:new Map(), key:null, hash:null, y:0};
 let page = "apps";
 // Reuse the existing live lists and form handlers in their new destinations.
@@ -5600,6 +5808,7 @@ function showPage(e) {
   }
   if (tool === 'macview') loadMacView();
   if (tool === 'panels') loadPanelSwitcher();
+  if (tool === 'backup') loadBackups();
   if (tool === 'androidSettings') {
     $('repNew').hidden = false; $('androidSettings').prepend($('repNew')); loadDisplays();
   }
@@ -6992,6 +7201,9 @@ api("/api/host").then(h => {
   Object.assign(HOST, h);
   window.frameControlCenter?.host(h);
   $("macToolLink").hidden = h.mobile || h.os !== "macOS";
+  $("pcToolLink").hidden = h.mobile || h.os !== "Windows";
+  if (!h.mobile && h.os === "Windows") TOOL_TITLES.macview = "PC in the headset";
+  $("backupToolLink").hidden = !!h.mobile;  // backups are folders on a computer
   if (h.mobile) return;
   $("offSetup").hidden = false; $("offSetup").onclick = setUpActive;  // the server opens it in a terminal
   watchConnection();

ui/mac-view.html

@@ -22,7 +22,7 @@
 </head>
 <body>
 <canvas id="c" width="16" height="9"></canvas>
-<div id="note">Connecting to the Mac…</div>
+<div id="note">Connecting to your computer…</div>
 <div id="hud" hidden></div>
 <script>
 "use strict";
@@ -243,14 +243,14 @@ async function connect() {
     // Refused before ever getting a key: the ticket expired or was revoked,
     // and retrying can't help.
     if (!reconnectKey && ++failedStarts >= 3) {
-      show("This view has expired. Press Show in Frame Control on the Mac to open it again.");
+      show("This view has expired. Press Show in Frame Control on your computer to open it again.");
       return;
     }
     hideNoteOnFrame = true;
     // The Mac may be asleep or the tunnel restarting: keep trying.
     retry = Math.min(retry + 1, 6);
     // Keep the Mac's reason (a missing permission, a closed window) on screen.
-    show(lastError ? `${lastError} Retrying…` : "Lost the Mac. Reconnecting…");
+    show(lastError ? `${lastError} Retrying…` : "Lost the computer. Reconnecting…");
     setTimeout(connect, 500 * 2 ** retry);
   };
 }
@@ -269,7 +269,7 @@ function control(m) {
     document.title = tag ? `${name} [${tag}]` : name;
     if (!m.input) {
       hideNoteOnFrame = false;  // a warning, not a connection notice: let it stay its 8 s
-      show("Clicks and keys need Accessibility permission on the Mac (Frame Control asks for it).", 8000);
+      show(m.inputMessage || "Clicks and keys need Accessibility permission on the Mac (Frame Control asks for it).", 8000);
     }
   } else if (m.t === "error") {
     stats.errors.push(m.message);
@@ -391,7 +391,7 @@ addEventListener("keydown", e => onKey(e, true));
 addEventListener("keyup", e => onKey(e, false));
 addEventListener("blur", () => send({ t: "release" }));
 
-show("Connecting to the Mac…");
+show("Connecting to your computer…");
 connect();
 </script>
 </body>

ui/server.py

@@ -45,6 +45,7 @@ import frame_agent  # noqa: E402
 import frame_assistant  # noqa: E402
 import frame_android  # noqa: E402
 import frame_android_import  # noqa: E402
+import frame_backup  # noqa: E402
 from apk_sources import search as apk_search, SourceError  # noqa: E402
 from apk_sources import fdroid as apk_fdroid  # noqa: E402
 import frame_apk_versions  # noqa: E402
@@ -58,6 +59,7 @@ import frame_contact  # noqa: E402
 import frame_host  # noqa: E402
 import frame_link  # noqa: E402
 import frame_macview  # noqa: E402
+import frame_pcview  # noqa: E402
 import frame_media  # noqa: E402
 import frame_panels  # noqa: E402
 import frame_quest  # noqa: E402
@@ -2695,6 +2697,73 @@ def panels_action(body):
     return result
 
 
+# ---- Backup and recovery kit (frame_backup.py) ------------------------------
+#
+# Backups are folders on this computer, so they run from the computer app only. One backup
+# or restore at a time: both are long jobs the page follows through /api/job.
+
+_backup_lock = threading.Lock()
+
+
+def backup_action(body):
+    action = body.get("action")
+    if LOCAL:
+        raise Failure("Backups are made from Frame Control on your computer", 400)
+    if action in ("plan", "restore") or (action == "open" and body.get("name") is not None):
+        try:
+            frame_backup.backup_path(body.get("name"))  # refused before anything reads or runs
+        except frame_backup.BackupError as e:
+            raise Failure(str(e), 400)
+    if action in ("gamemode", "restore") and body.get("confirm") is not True:
+        raise Failure("Confirm first: this changes the headset", 400)
+    if action == "list":
+        return frame_backup.list_backups()
+    if action == "preview":
+        return frame_backup.preview()
+    if action == "plan":
+        return frame_backup.restore_plan(body.get("name"))
+    if action == "session":
+        return frame_backup.session_status()
+    if action == "gamemode":
+        return frame_backup.return_to_game_mode(confirmed=True)
+    if action == "open":
+        folder = frame_backup.backup_root()
+        if body.get("name") is not None:
+            folder = frame_backup.backup_path(body.get("name"))
+        folder.mkdir(parents=True, exist_ok=True)
+        try:
+            frame_host.open_path(folder)
+        except frame_host.HostError as e:
+            raise Failure(str(e), 500)
+        return {"message": f"Opened {folder} in {frame_host.FILE_MANAGER}"}
+    if action == "backup":
+        kinds = body.get("kinds", list(frame_backup.KINDS))
+        if not isinstance(kinds, list) or not kinds or any(k not in frame_backup.KINDS for k in kinds):
+            raise Failure("Choose what to back up", 400)
+        name = agent_target()["name"]
+        work = lambda report: frame_backup.backup(report, kinds, headset=name)  # noqa: E731
+        label = "Back up the Frame"
+    elif action == "restore":
+        name, ids = body.get("name"), body.get("parts")
+        if not isinstance(ids, list) or not ids or not all(
+                isinstance(i, str) and frame_backup.PART.fullmatch(i) for i in ids):
+            raise Failure("Choose what to restore", 400)
+        work = lambda report: frame_backup.restore(name, ids, True, report)  # noqa: E731
+        label = "Restore from backup"
+    else:
+        raise Failure("Unknown backup action", 400)
+
+    def exclusive(report):
+        if not _backup_lock.acquire(blocking=False):
+            raise Failure("A backup or restore is already running", 409)
+        try:
+            return work(report)
+        finally:
+            _backup_lock.release()
+    ensure_master()
+    return start_job(label, exclusive, progress=True)
+
+
 # ---- Our Frame-side media player -----------------------------------------
 
 _MEDIA_LOCK = threading.Lock()
@@ -2764,12 +2833,13 @@ def push_media(path):
             "id": token + "/" + name}
 
 
-# ---- Mac in the headset (frame_macview.py) ----------------------------------
+# ---- Mac in the headset (frame_macview.py), PC in the headset (frame_pcview.py) ----
 
 # The tunnel gets its own connection: the shared master's options would win
 # over anything added after them.
-macview = frame_macview.MacView(["ssh", "-o", "BatchMode=yes", "-o", "ConnectTimeout=8"],
-                                lambda remote, stdin=None, timeout=30: ssh(remote, stdin=stdin, timeout=timeout),
+macview = frame_pcview.host_view(["ssh", "-o", "BatchMode=yes", "-o", "ConnectTimeout=8"],
+                                lambda remote, stdin=None, timeout=30: ssh(remote, stdin=stdin.encode("utf-8") if stdin is not None else None,
+                                                                           timeout=timeout, text=False).decode("utf-8", errors="replace"),
                                 FRAME, track=_live_tunnels.add)
 
 
@@ -2786,7 +2856,8 @@ def macview_state(query=None):
 
 
 def macview_action(body):
-    """{action: show|stop|permissions, src, quality, w, h}."""
+    """{action: show|stop|permissions, src, quality, w, h} | {action: enable, on}.
+    enable turns PC in the headset (Experimental, Windows only) on or off."""
     if LOCAL:
         raise Failure("Runs on your computer, not the headset.", 400)
     action = body.get("action")
@@ -2799,6 +2870,10 @@ def macview_action(body):
             return macview.stop(body.get("src") or None)
         if action == "permissions":
             return macview.request_permissions()
+        if action == "enable":
+            if not isinstance(macview, frame_pcview.PCView):
+                raise Failure("PC in the headset is only available on Windows.", 400)
+            return macview.set_enabled(body.get("on") is True)
     except frame_macview.MacViewError as e:
         raise Failure(str(e), 502)
     raise Failure("unknown action", 400)
@@ -2927,7 +3002,7 @@ def source_manage(body):
 
 
 POST = {
-    "/api/android/backup": android_backup,
+    "/api/android/backup": android_backup, "/api/backup": backup_action,
     "/api/vr": vr,
     "/api/comfort": comfort, "/api/media": media, "/api/agent/call": agent_call,
     "/api/agent/approval": agent_approval, "/api/assistant/chat": assistant_chat,