Video on Android/Linux renders in a webview <video> element, and the
frontend facade short-circuited play/pause/toggle straight into the
adapter whenever one was registered. Html5PlayerAdapter.toggle() then
decided play-vs-pause by reading el.paused off the DOM, so the Rust
controller never saw the intent and could not serialise competing ones.
el.paused flips transiently while an element buffers or settles a seek.
Two intents ~150ms apart therefore read *different* values and performed
*opposing* actions — one playing, one pausing — which self-sustained a
play/pause loop that needed no further input. On device this showed up
as a fully healthy element (readyState=4, networkState=1, not seeking,
not buffering, not ended) pausing itself roughly once a second, so
unpausing or skipping ahead bounced straight back to paused.
The root cause was that Rust held NO state for webview-rendered media:
report_html5_state only re-emitted its argument, despite the comment
above it claiming the controller was the single source of truth. It had
nothing to decide a toggle from.
Now report_html5_state tracks the reported state, and play/pause/toggle
consult it and drive the element by emitting a ControlCommand — the same
"backend decides, adapter executes the primitive" split player_seek_video
already uses. A stopped/idle report clears the tracking so MPV/ExoPlayer
regain authority for music playback.
Tests cover the loop signature directly (repeated toggles must alternate,
never repeat or oppose) plus a guard that one intent yields exactly one
ControlCommand — which matters on Windows, where the backend is itself
webview-based and could otherwise be driven twice.
Html5PlayerAdapter.play() reported every interrupted play attempt as a
player error. While an HLS stream stalls, hls.js' gap-controller nudges
the element to recover, which cancels the pending play() promise and
raises AbortError ("play() request was interrupted by a call to
pause()"). That is transient — the element is still trying to play — but
it hit host.onError roughly once a second for the whole stall, leaving
the UI stuck reporting paused.
Treat an interrupted play as a debug-level non-event, and memoise the
in-flight attempt so the UI and recovery paths share one element.play()
rather than stacking calls that abort each other.
This is the loop amplifier, complementing DR-095 which removed the
dead-segment stall that triggered it.
Note: webviewAudioAdapter.play() has the same raw shape but is not
implicated — audio playback does not go through hls.js — so it is left
unchanged rather than widening this fix.
Investigation into unifying the playback backends (Linux/MPV, Android/ExoPlayer,
Windows/webview) onto one engine with hardware acceleration. Conclusion: video
cannot be unified onto a native engine; audio can.
The blocker is not mpv-specific. WebKitGTK, WebView2 and Android WebView each
draw into their own compositor surface, so a native video surface sits either
entirely above or entirely below the webview and cannot interleave with HTML.
GStreamer and libVLC fail identically. mpv would additionally regress streaming:
it has no adaptive bitrate, while the current hls.js path does.
Six specs added:
- playback-backend-unification: the analysis and decision, with evidence
- android-audio-settings-parity: set_audio_settings on ExoPlayerBackend
- android-native-video-spike: timeboxed test of SurfaceView compositing
- windows-native-audio-backend: replace the webview <audio> shim with libmpv
- libmpv2-migration: dead libmpv git pin -> libmpv2, plus a LICENSE file
- playback-docs-corrections: the requirement-status fixes applied here
Corrections to requirements.md, all verified against source:
- UR-031/DR-034 claimed crossfade was "Done (Linux only)". It is implemented
nowhere (mpv_backend.rs has a bare TODO) and is architecturally blocked on
mpv, whose single-stream audio chain cannot feed acrossfade's two inputs.
- Parity matrix listed crossfade as a Linux/Android gap; it is neither.
- The matrix omitted the equalizer, which has the same Linux-only shape.
- The suggested ConcatenatingMediaSource is deprecated in current Media3.
nativeAdapter.ts cited tauri#10152 as an upstream blocker for native Android
video. That issue is a stale feature request, dead since 2024-07-01; the
capability shipped in tauri 27d01834 (2024-09-02), and the related
black-screen bug was fixed in wry 0.39.4 (we ship 0.55.x). What is genuinely
unproven is SurfaceView-behind-WebView compositing, which the spike now tracks.
Adds WebviewAudioBackend, used on non-Linux/non-Android targets (e.g.
Windows) where there is no libmpv/ExoPlayer. Instead of decoding, it
emits a WebviewAudioLoad event with the stream URL; a frontend <audio>
element (WebviewAudioAdapter + webviewAudio service) plays it and reports
state/position back through the existing player_report_* round-trip, so
the Rust PlayerController stays the single source of truth. Play/pause/
seek reach the element via the existing ControlCommand event.
All video already renders in the webview on every platform, so this
completes audio-only playback for Windows (video via WebView2, audio via
<audio>). Pure Rust + Tauri events, so it still cross-compiles from Linux.
Regenerates bindings.ts (adds webview_audio_load; also carries the
equalizer EQ bindings).
TRACES: UR-003, UR-004, UR-005 | DR-004
Hand video playback off to a native audio-only stream when the app is
backgrounded or locked, with no on-device video decode (UR-040). Adds
player_enter/exit_background_audio commands, an audio-only stream URL
for video items across the repository layer, and the frontend handoff
state machine wired into VideoPlayer. Includes accompanying
repository/offline/player refactoring and regenerates the traceability
matrix.
Establish a decoupled player boundary so UI and backend interact with video
through one contract, with the HTML5 (Linux/interim-Android) and native
(ExoPlayer) providers as interchangeable primitive-executor adapters.
- PlayerAdapter interface + AdapterHost callback bag (adapters/types.ts): the
adapter owns only decision-free element PRIMITIVES (seekElement, reloadSource,
play/pause, setVolume, selectSubtitle); it never branches on strategy.
- Seek/audio-track DECISIONS stay in Rust (player_seek_video / _switch_audio_track
return a strategy); the facade dispatches the chosen primitive to the active
adapter. Both providers share the one decision path — logic lives once, in Rust.
- Facade holds the active adapter; a new ControlCommand PlayerStatusEvent lets
backend control (lockscreen/remote/sleep) drive the webview <video> element.
- Html5PlayerAdapter resolves the LIVE element via the bridge (fixes play/pause
silently no-opping when the element was re-bound).
- Do not emit a "stopped" player state on natural end-of-video: it flipped the
player/mode to idle mid-handoff and suppressed next-episode auto-advance under
a sleep timer. Jellyfin progress reporting is preserved; the backend's
on_video_playback_ended owns the transition.
- VideoPlayer net -300 lines (strategy/HLS-reload logic relocated to the adapter).
- Adds 20 adapter unit tests; existing suites stay green (vitest 457, cargo 416).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
dtourolle
