Skip to main content

## MpvBackend

# Struct MpvBackend

Source

    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>>>,
    }

Expand description

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§

Source §

### impl MpvBackend

Source

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

Create a new MPV backend

Source

#### fn start_event_loop(&self)

Start the MPV event loop in a background thread

## Trait Implementations§

Source §

### impl Drop for MpvBackend

Source §

#### fn drop(&mut self)

Executes the destructor for this type. Read more
Source §

#### 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. Read more
Source §

### impl PlayerBackend for MpvBackend

Source §

#### 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

Source §

#### 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

Source §

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

Load a media item for playback TRACES: UR-005
Source §

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

Start or resume playback TRACES: UR-005
Source §

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

Pause playback TRACES: UR-005
Source §

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

Stop playback and unload media TRACES: UR-005
Source §

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

Seek to a position in seconds TRACES: UR-005
Source §

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

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

#### fn state(&self) -> PlayerState

Get current player state
Source §

#### fn volume(&self) -> f32

Get current volume
Source §

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

Apply audio settings (crossfade, gapless, normalization) Read more
Source §

#### fn audio_settings(&self) -> AudioSettings

Get current audio settings Read more
Source §

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

Set the active audio track by stream index Read more
Source §

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

Set the active subtitle track by stream index (None to disable subtitles) Read more

## Auto Trait Implementations§

§

### impl Freeze for MpvBackend

§

### impl !RefUnwindSafe for MpvBackend

§

### impl Send for MpvBackend

§

### impl Sync for MpvBackend

§

### impl Unpin for MpvBackend

§

### impl UnsafeUnpin for MpvBackend

§

### impl !UnwindSafe for MpvBackend

## Blanket Implementations§

Source §

### impl<T> Any for T
where T: 'static + ?Sized,

Source §

#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
Source §

### impl<T> Borrow<T> for T
where T: ?Sized,

Source §

#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
Source §

### impl<T> BorrowMut<T> for T
where T: ?Sized,

Source §

#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
Source §

### impl<T> From<T> for T

Source §

#### fn from(t: T) -> T

Returns the argument unchanged.

§

### impl<T> Instrument for T

§

#### fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided [`Span`], returning an `Instrumented` wrapper. Read more
§

#### fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current `Span`, returning an `Instrumented` wrapper. Read more
Source §

### impl<T, U> Into<U> for T
where U: From<T>,

Source §

#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

§

### impl<T> PolicyExt for T
where T: ?Sized,

§

#### fn and<P, B, E>(self, other: P) -> And<T, P>
where T: Policy<B, E>, P: Policy<B, E>,

Create a new `Policy` that returns [`Action::Follow`] only if `self` and `other` return `Action::Follow`. Read more
§

#### fn or<P, B, E>(self, other: P) -> Or<T, P>
where T: Policy<B, E>, P: Policy<B, E>,

Create a new `Policy` that returns [`Action::Follow`] if either `self` or `other` returns `Action::Follow`. Read more
Source §

### impl<T> Same for T

Source §

#### type Output = T

Should always be `Self`
Source §

### impl<T, U> TryFrom<U> for T
where U: Into<T>,

Source §

#### type Error = Infallible

The type returned in the event of a conversion error.
Source §

#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
Source §

### impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

Source §

#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
Source §

#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
§

### impl<V, T> VZip<V> for T
where V: MultiLane<T>,

§

#### fn vzip(self) -> V

§

### impl<T> WithSubscriber for T

§

#### fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided `Subscriber` to this type, returning a [`WithDispatch`] wrapper. Read more
§

#### fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default `Subscriber` to this type, returning a [`WithDispatch`] wrapper. Read more