Struct MpvBackend 

pub struct MpvBackend {
    mpv: Arc<Mpv>,
    state: Arc<Mutex<InternalState>>,
    event_emitter: Option<Arc<dyn PlayerEventEmitter>>,
    audio_settings: AudioSettings,
    playback_reporter: Arc<Mutex<Option<PlaybackReporter>>>,
    position_throttler: Arc<EventThrottler>,
    last_seek_time: Arc<AtomicU64>,
    observed: Arc<Mutex<ObservedTime>>,
    pending_seek: Arc<Mutex<Option<f64>>>,
}

MPV-based player backend for Linux

Uses libmpv for audio playback with full control over playback state, position tracking, and event handling.

Fields

mpv: Arc<Mpv>

state: Arc<Mutex<InternalState>>

event_emitter: Option<Arc<dyn PlayerEventEmitter>>

audio_settings: AudioSettings

playback_reporter: Arc<Mutex<Option<PlaybackReporter>>>

position_throttler: Arc<EventThrottler>

last_seek_time: Arc<AtomicU64>

observed: Arc<Mutex<ObservedTime>>

Last position/duration seen while a file was loaded.

time-pos and duration are live properties of the loaded file: at EOF MPV unloads it and both stop resolving, so reading them straight through reported 0.0 / unknown exactly when end-of-file handling needed to know where playback reached. See ObservedTime.

pending_seek: Arc<Mutex<Option<f64>>>

A seek that arrived before MPV had a file to seek in.

loadfile is asynchronous: it returns as soon as the command is queued, so time-pos is not yet a resolvable property and setting it fails. A seek issued in that window used to be dropped on the floor, and the two callers that do exactly this are the ones a viewer notices — resume, and a transcoded seek, both of which re-open the stream and then ask for a position. The stream reloaded and played from zero.

Held here and applied by the FileLoaded arm.

TRACES: UR-040, UR-005 | DR-241

Implementations

impl MpvBackend

pub fn new( event_emitter: Option<Arc<dyn PlayerEventEmitter>>, playback_reporter: Arc<TokioMutex<Option<PlaybackReporter>>>, position_throttler: Arc<EventThrottler>, video_window: Option<i64>, ) -> Result<Self, PlayerError>

Create a new MPV backend

video_window is the app window’s native handle (an HWND), which mpv draws video into on Windows; None elsewhere.

fn start_event_loop(&self)

Start the MPV event loop in a background thread

Trait Implementations

impl Drop for MpvBackend

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl PlayerBackend for MpvBackend

fn position(&self) -> f64

Current position — the live time-pos, or the last one observed while a file was loaded.

The fallback is the point: time-pos is a property of the loaded file, so at EOF it stops resolving and a bare unwrap_or(0.0) reported 0:00 at exactly the moment end-of-file handling asks where playback reached.

TRACES: UR-005 | DR-130 | UT-121

fn duration(&self) -> Option<f64>

Total duration — live, or the last one observed. Unloaded at EOF for the same reason as position.

TRACES: UR-005 | DR-130 | UT-121

fn set_audio_track(&mut self, stream_index: i32) -> Result<(), PlayerError>

stream_index is a position: the n-th audio track of the file, the same meaning ExoPlayer gives it (player_switch_audio_track passes the array index). Only reached for a direct play/stream — a transcode carries one track and is re-opened instead.

TRACES: UR-021 | IR-019, DR-024, DR-235

fn set_subtitle_track( &mut self, stream_index: Option<i32>, ) -> Result<(), PlayerError>

stream_index is the position in the sideloaded subtitle list the play request carried (nativeSubtitleArrayIndex), None to hide subtitles.

TRACES: UR-020 | IR-018, DR-023, DR-235

fn load(&mut self, media: &MediaItem) -> Result<(), PlayerError>

Load a media item for playback TRACES: UR-005

fn play(&mut self) -> Result<(), PlayerError>

Start or resume playback TRACES: UR-005

fn pause(&mut self) -> Result<(), PlayerError>

Pause playback TRACES: UR-005

fn stop(&mut self) -> Result<(), PlayerError>

Stop playback and unload media TRACES: UR-005

fn seek(&mut self, position: f64) -> Result<(), PlayerError>

Seek to a position in seconds TRACES: UR-005

fn set_volume(&mut self, volume: f32) -> Result<(), PlayerError>

Set volume (0.0 - 1.0) TRACES: UR-016

fn state(&self) -> PlayerState

Get current player state

fn volume(&self) -> f32

Get current volume

fn set_audio_settings( &mut self, settings: &AudioSettings, ) -> Result<(), PlayerError>

Apply audio settings (crossfade, gapless, normalization)

fn audio_settings(&self) -> AudioSettings

Get current audio settings