MediaPeriod (ExoPlayer library)

All Superinterfaces:

SequenceableLoader

All Known Implementing Classes:

ClippingMediaPeriod, FakeAdaptiveMediaPeriod, FakeMediaPeriod, HlsMediaPeriod, MaskingMediaPeriod
```
public interface MediaPeriod
extends SequenceableLoader
```
Loads media corresponding to a Timeline.Period, and allows that media to be read. All methods are called on the player's internal playback thread, as described in the ExoPlayer Javadoc.
A MediaPeriod may only able to provide one SampleStream corresponding to a group at any given time, however this SampleStream may adapt between multiple tracks within the group.

Nested Class Summary

Nested Classes
Modifier and Type Interface Description

static interface MediaPeriod.Callback
A callback to be notified of MediaPeriod events.

Nested Classes
Modifier and Type	Interface	Description
`static interface`	`MediaPeriod.Callback`	A callback to be notified of `MediaPeriod` events.

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`boolean`	`continueLoading(long positionUs)`	Attempts to continue loading.
`void`	`discardBuffer(long positionUs, boolean toKeyframe)`	Discards buffered media up to the specified position.
`long`	`getAdjustedSeekPositionUs(long positionUs, SeekParameters seekParameters)`	Returns the position to which a seek will be performed, given the specified seek position and `SeekParameters`.
`long`	`getBufferedPositionUs()`	Returns an estimate of the position up to which data is buffered for the enabled tracks.
`long`	`getNextLoadPositionUs()`	Returns the next load time, or `C.TIME_END_OF_SOURCE` if loading has finished.
`default List<StreamKey>`	`getStreamKeys(List<ExoTrackSelection> trackSelections)`	Returns a list of `StreamKeys` which allow to filter the media in this period to load only the parts needed to play the provided `TrackSelections`.
`TrackGroupArray`	`getTrackGroups()`	Returns the `TrackGroup`s exposed by the period.
`boolean`	`isLoading()`	Returns whether the media period is currently loading.
`void`	`maybeThrowPrepareError()`	Throws an error that's preventing the period from becoming prepared.
`void`	`prepare(MediaPeriod.Callback callback, long positionUs)`	Prepares this media period asynchronously.
`long`	`readDiscontinuity()`	Attempts to read a discontinuity.
`void`	`reevaluateBuffer(long positionUs)`	Re-evaluates the buffer given the playback position.
`long`	`seekToUs(long positionUs)`	Attempts to seek to the specified position in microseconds.
`long`	`selectTracks(@NullableType ExoTrackSelection[] selections, boolean[] mayRetainStreamFlags, @NullableType SampleStream[] streams, boolean[] streamResetFlags, long positionUs)`	Performs a track selection.

- Method Detail
  - prepare
```
void prepare(MediaPeriod.Callback callback,
             long positionUs)
```
    Prepares this media period asynchronously.
    callback.onPrepared is called when preparation completes. If preparation fails, maybeThrowPrepareError() will throw an IOException.
    If preparation succeeds and results in a source timeline change (e.g. the period duration becoming known), MediaSource.MediaSourceCaller.onSourceInfoRefreshed(MediaSource, Timeline) will be called before callback.onPrepared.
    
    Parameters:
    
    callback - Callback to receive updates from this period, including being notified when preparation completes.
    
    positionUs - The expected starting position, in microseconds.
  - maybeThrowPrepareError
```
void maybeThrowPrepareError()
                     throws IOException
```
    Throws an error that's preventing the period from becoming prepared. Does nothing if no such error exists.
    This method is only called before the period has completed preparation.
    
    Throws:
    
    IOException - The underlying error.
  - getTrackGroups
```
TrackGroupArray getTrackGroups()
```
    Returns the TrackGroups exposed by the period.
    This method is only called after the period has been prepared.
    
    Returns:
    
    The TrackGroups.
  - getStreamKeys
```
default List<StreamKey> getStreamKeys(List<ExoTrackSelection> trackSelections)
```
    Returns a list of StreamKeys which allow to filter the media in this period to load only the parts needed to play the provided TrackSelections.
    This method is only called after the period has been prepared.
    
    Parameters:
    
    trackSelections - The TrackSelections describing the tracks for which stream keys are requested.
    
    Returns:
    
    The corresponding StreamKeys for the selected tracks, or an empty list if filtering is not possible and the entire media needs to be loaded to play the selected tracks.
  - selectTracks
```
long selectTracks(@NullableType ExoTrackSelection[] selections,
                  boolean[] mayRetainStreamFlags,
                  @NullableType SampleStream[] streams,
                  boolean[] streamResetFlags,
                  long positionUs)
```
    Performs a track selection.
    The call receives track selections for each renderer, mayRetainStreamFlags indicating whether the existing SampleStream can be retained for each selection, and the existing streams themselves. The call will update streams to reflect the provided selections, clearing, setting and replacing entries as required. If an existing sample stream is retained but with the requirement that the consuming renderer be reset, then the corresponding flag in streamResetFlags will be set to true. This flag will also be set if a new sample stream is created.
    Note that previously passed TrackSelections are no longer valid, and any references to them must be updated to point to the new selections.
    This method is only called after the period has been prepared.
    
    Parameters:
    
    selections - The renderer track selections.
    
    mayRetainStreamFlags - Flags indicating whether the existing sample stream can be retained for each track selection. A true value indicates that the selection is equivalent to the one that was previously passed, and that the caller does not require that the sample stream be recreated. If a retained sample stream holds any references to the track selection then they must be updated to point to the new selection.
    
    streams - The existing sample streams, which will be updated to reflect the provided selections.
    
    streamResetFlags - Will be updated to indicate new sample streams, and sample streams that have been retained but with the requirement that the consuming renderer be reset.
    
    positionUs - The current playback position in microseconds. If playback of this period has not yet started, the value will be the starting position.
    
    Returns:
    
    The actual position at which the tracks were enabled, in microseconds.
  - discardBuffer
```
void discardBuffer(long positionUs,
                   boolean toKeyframe)
```
    Discards buffered media up to the specified position.
    This method is only called after the period has been prepared.
    
    Parameters:
    
    positionUs - The position in microseconds.
    
    toKeyframe - If true then for each track discards samples up to the keyframe before or at the specified position, rather than any sample before or at that position.
  - readDiscontinuity
```
long readDiscontinuity()
```
    Attempts to read a discontinuity.
    After this method has returned a value other than C.TIME_UNSET, all SampleStreams provided by the period are guaranteed to start from a key frame.
    This method is only called after the period has been prepared and before reading from any SampleStreams provided by the period.
    
    Returns:
    
    If a discontinuity was read then the playback position in microseconds after the discontinuity. Else C.TIME_UNSET.
  - seekToUs
```
long seekToUs(long positionUs)
```
    Attempts to seek to the specified position in microseconds.
    After this method has been called, all SampleStreams provided by the period are guaranteed to start from a key frame.
    This method is only called when at least one track is selected.
    
    Parameters:
    
    positionUs - The seek position in microseconds.
    
    Returns:
    
    The actual position to which the period was seeked, in microseconds.
  - getAdjustedSeekPositionUs
```
long getAdjustedSeekPositionUs(long positionUs,
                               SeekParameters seekParameters)
```
    Returns the position to which a seek will be performed, given the specified seek position and SeekParameters.
    This method is only called after the period has been prepared.
    
    Parameters:
    
    positionUs - The seek position in microseconds.
    
    seekParameters - Parameters that control how the seek is performed. Implementations may apply seek parameters on a best effort basis.
    
    Returns:
    
    The actual position to which a seek will be performed, in microseconds.
  - getBufferedPositionUs
```
long getBufferedPositionUs()
```
    Returns an estimate of the position up to which data is buffered for the enabled tracks.
    This method is only called when at least one track is selected.
    
    Specified by:
    
    getBufferedPositionUs in interface SequenceableLoader
    
    Returns:
    
    An estimate of the absolute position in microseconds up to which data is buffered, or C.TIME_END_OF_SOURCE if the track is fully buffered.
  - getNextLoadPositionUs
```
long getNextLoadPositionUs()
```
    Returns the next load time, or C.TIME_END_OF_SOURCE if loading has finished.
    This method is only called after the period has been prepared. It may be called when no tracks are selected.
    
    Specified by:
    
    getNextLoadPositionUs in interface SequenceableLoader
  - continueLoading
```
boolean continueLoading(long positionUs)
```
    Attempts to continue loading.
    This method may be called both during and after the period has been prepared.
    A period may call SequenceableLoader.Callback.onContinueLoadingRequested(SequenceableLoader) on the MediaPeriod.Callback passed to prepare(Callback, long) to request that this method be called when the period is permitted to continue loading data. A period may do this both during and after preparation.
    
    Specified by:
    
    continueLoading in interface SequenceableLoader
    
    Parameters:
    
    positionUs - The current playback position in microseconds. If playback of this period has not yet started, the value will be the starting position in this period minus the duration of any media in previous periods still to be played.
    
    Returns:
    
    True if progress was made, meaning that getNextLoadPositionUs() will return a different value than prior to the call. False otherwise.
  - isLoading
```
boolean isLoading()
```
    Returns whether the media period is currently loading.
    
    Specified by:
    
    isLoading in interface SequenceableLoader
  - reevaluateBuffer
```
void reevaluateBuffer(long positionUs)
```
    Re-evaluates the buffer given the playback position.
    This method is only called after the period has been prepared.
    A period may choose to discard buffered media or cancel ongoing loads so that media can be re-buffered in a different quality.
    
    Specified by:
    
    reevaluateBuffer in interface SequenceableLoader
    
    Parameters:
    
    positionUs - The current playback position in microseconds. If playback of this period has not yet started, the value will be the starting position in this period minus the duration of any media in previous periods still to be played.

Interface MediaPeriod

Nested Class Summary

Method Summary

Method Detail

prepare

maybeThrowPrepareError

getTrackGroups

getStreamKeys

selectTracks

discardBuffer

readDiscontinuity

seekToUs

getAdjustedSeekPositionUs

getBufferedPositionUs

getNextLoadPositionUs

continueLoading

isLoading

reevaluateBuffer