com.google.android.exoplayer.dash

Class DashChunkSource

java.lang.Object

com.google.android.exoplayer.dash.DashChunkSource

All Implemented Interfaces:

ChunkSource, DashTrackSelector.Output

public class DashChunkSource
extends Object
implements ChunkSource, DashTrackSelector.Output

An ChunkSource for DASH streams.

This implementation currently supports fMP4, webm, webvtt and ttml.

This implementation makes the following assumptions about multi-period manifests:

1. that new periods will contain the same representations as previous periods (i.e. no new or missing representations) and
2. that representations are contiguous across multiple periods

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	DashChunkSource.EventListener Interface definition for a callback to be notified of DashChunkSource events.
protected static class	DashChunkSource.ExposedTrack
static class	DashChunkSource.NoAdaptationSetException Thrown when an AdaptationSet is missing from the MPD.
protected static class	DashChunkSource.PeriodHolder
protected static class	DashChunkSource.RepresentationHolder

Constructor Summary

Constructors

Constructor and Description
DashChunkSource(DashTrackSelector trackSelector, DataSource dataSource, FormatEvaluator adaptiveFormatEvaluator, long durationMs, int adaptationSetType, List<Representation> representations) Lightweight constructor to use for fixed duration content.
DashChunkSource(DashTrackSelector trackSelector, DataSource dataSource, FormatEvaluator adaptiveFormatEvaluator, long durationMs, int adaptationSetType, Representation... representations) Lightweight constructor to use for fixed duration content.
DashChunkSource(ManifestFetcher<MediaPresentationDescription> manifestFetcher, DashTrackSelector trackSelector, DataSource dataSource, FormatEvaluator adaptiveFormatEvaluator, long liveEdgeLatencyMs, long elapsedRealtimeOffsetMs, boolean startAtLiveEdge, Handler eventHandler, DashChunkSource.EventListener eventListener, int eventSourceId) Constructor to use for live DVR streaming.
DashChunkSource(ManifestFetcher<MediaPresentationDescription> manifestFetcher, DashTrackSelector trackSelector, DataSource dataSource, FormatEvaluator adaptiveFormatEvaluator, long liveEdgeLatencyMs, long elapsedRealtimeOffsetMs, Handler eventHandler, DashChunkSource.EventListener eventListener, int eventSourceId) Constructor to use for live streaming.
DashChunkSource(MediaPresentationDescription manifest, DashTrackSelector trackSelector, DataSource dataSource, FormatEvaluator adaptiveFormatEvaluator) Constructor to use for fixed duration content.

Method Summary

Modifier and Type	Method and Description
void	adaptiveTrack(MediaPresentationDescription manifest, int periodIndex, int adaptationSetIndex, int[] representationIndices) Outputs an adaptive track, covering the specified representations in the specified adaptation set.
void	continueBuffering(long playbackPositionUs) Indicates to the source that it should still be checking for updates to the stream.
void	disable(List<? extends MediaChunk> queue) Disables the source.
void	enable(int track) Enable the source for the specified track.
void	fixedTrack(MediaPresentationDescription manifest, int periodIndex, int adaptationSetIndex, int representationIndex) Outputs an fixed track corresponding to the specified representation in the specified adaptation set.
void	getChunkOperation(List<? extends MediaChunk> queue, long playbackPositionUs, ChunkOperationHolder out) Updates the provided ChunkOperationHolder to contain the next operation that should be performed by the calling ChunkSampleSource.
MediaFormat	getFormat(int track) Gets the format of the specified track.
int	getTrackCount() Returns the number of tracks exposed by the source.
void	maybeThrowError() If the source is currently having difficulty preparing or providing chunks, then this method throws the underlying error.
protected Chunk	newMediaChunk(DashChunkSource.PeriodHolder periodHolder, DashChunkSource.RepresentationHolder representationHolder, DataSource dataSource, MediaFormat mediaFormat, DashChunkSource.ExposedTrack enabledTrack, int segmentNum, int trigger, boolean isMediaFormatFinal)
void	onChunkLoadCompleted(Chunk chunk) Invoked when the ChunkSampleSource has finished loading a chunk obtained from this source.
void	onChunkLoadError(Chunk chunk, Exception e) Invoked when the ChunkSampleSource encounters an error loading a chunk obtained from this source.
boolean	prepare() Prepares the source.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DashChunkSource

public DashChunkSource(DashTrackSelector trackSelector,
                       DataSource dataSource,
                       FormatEvaluator adaptiveFormatEvaluator,
                       long durationMs,
                       int adaptationSetType,
                       Representation... representations)

Lightweight constructor to use for fixed duration content.

Parameters:

trackSelector - Selects tracks to be exposed by this source.

dataSource - A DataSource suitable for loading the media data.

adaptiveFormatEvaluator - For adaptive tracks, selects from the available formats.

durationMs - The duration of the content.

adaptationSetType - The type of the adaptation set to which the representations belong. One of AdaptationSet.TYPE_AUDIO, AdaptationSet.TYPE_VIDEO and AdaptationSet.TYPE_TEXT.

representations - The representations to be considered by the source.

DashChunkSource

public DashChunkSource(DashTrackSelector trackSelector,
                       DataSource dataSource,
                       FormatEvaluator adaptiveFormatEvaluator,
                       long durationMs,
                       int adaptationSetType,
                       List<Representation> representations)

Lightweight constructor to use for fixed duration content.

Parameters:

trackSelector - Selects tracks to be exposed by this source.

dataSource - A DataSource suitable for loading the media data.

adaptiveFormatEvaluator - For adaptive tracks, selects from the available formats.

durationMs - The duration of the content.

adaptationSetType - The type of the adaptation set to which the representations belong. One of AdaptationSet.TYPE_AUDIO, AdaptationSet.TYPE_VIDEO and AdaptationSet.TYPE_TEXT.

representations - The representations to be considered by the source.

DashChunkSource

public DashChunkSource(MediaPresentationDescription manifest,
                       DashTrackSelector trackSelector,
                       DataSource dataSource,
                       FormatEvaluator adaptiveFormatEvaluator)

Constructor to use for fixed duration content.

Parameters:

manifest - The manifest.

trackSelector - Selects tracks from manifest periods to be exposed by this source.

dataSource - A DataSource suitable for loading the media data.

adaptiveFormatEvaluator - For adaptive tracks, selects from the available formats.

DashChunkSource

public DashChunkSource(ManifestFetcher<MediaPresentationDescription> manifestFetcher,
                       DashTrackSelector trackSelector,
                       DataSource dataSource,
                       FormatEvaluator adaptiveFormatEvaluator,
                       long liveEdgeLatencyMs,
                       long elapsedRealtimeOffsetMs,
                       Handler eventHandler,
                       DashChunkSource.EventListener eventListener,
                       int eventSourceId)

Constructor to use for live streaming.

May also be used for fixed duration content, in which case the call is equivalent to calling the other constructor, passing manifestFetcher.getManifest() is the first argument.

Parameters:

manifestFetcher - A fetcher for the manifest, which must have already successfully completed an initial load.

trackSelector - Selects tracks from manifest periods to be exposed by this source.

dataSource - A DataSource suitable for loading the media data.

adaptiveFormatEvaluator - For adaptive tracks, selects from the available formats.

liveEdgeLatencyMs - For live streams, the number of milliseconds that the playback should lag behind the "live edge" (i.e. the end of the most recently defined media in the manifest). Choosing a small value will minimize latency introduced by the player, however note that the value sets an upper bound on the length of media that the player can buffer. Hence a small value may increase the probability of rebuffering and playback failures.

elapsedRealtimeOffsetMs - If known, an estimate of the instantaneous difference between server-side unix time and SystemClock.elapsedRealtime() in milliseconds, specified as the server's unix time minus the local elapsed time. It unknown, set to 0.

eventHandler - A handler to use when delivering events to EventListener. May be null if delivery of events is not required.

eventListener - A listener of events. May be null if delivery of events is not required.

eventSourceId - An identifier that gets passed to eventListener methods.

DashChunkSource

public DashChunkSource(ManifestFetcher<MediaPresentationDescription> manifestFetcher,
                       DashTrackSelector trackSelector,
                       DataSource dataSource,
                       FormatEvaluator adaptiveFormatEvaluator,
                       long liveEdgeLatencyMs,
                       long elapsedRealtimeOffsetMs,
                       boolean startAtLiveEdge,
                       Handler eventHandler,
                       DashChunkSource.EventListener eventListener,
                       int eventSourceId)

Constructor to use for live DVR streaming.

Parameters:

manifestFetcher - A fetcher for the manifest, which must have already successfully completed an initial load.

trackSelector - Selects tracks from manifest periods to be exposed by this source.

dataSource - A DataSource suitable for loading the media data.

adaptiveFormatEvaluator - For adaptive tracks, selects from the available formats.

liveEdgeLatencyMs - For live streams, the number of milliseconds that the playback should lag behind the "live edge" (i.e. the end of the most recently defined media in the manifest). Choosing a small value will minimize latency introduced by the player, however note that the value sets an upper bound on the length of media that the player can buffer. Hence a small value may increase the probability of rebuffering and playback failures.

elapsedRealtimeOffsetMs - If known, an estimate of the instantaneous difference between server-side unix time and SystemClock.elapsedRealtime() in milliseconds, specified as the server's unix time minus the local elapsed time. It unknown, set to 0.

startAtLiveEdge - True if the stream should start at the live edge; false if it should at the beginning of the live window.

eventHandler - A handler to use when delivering events to EventListener. May be null if delivery of events is not required.

eventListener - A listener of events. May be null if delivery of events is not required.

eventSourceId - An identifier that gets passed to eventListener methods.

Method Detail

maybeThrowError

public void maybeThrowError()
                     throws IOException

Description copied from interface: ChunkSource

If the source is currently having difficulty preparing or providing chunks, then this method throws the underlying error. Otherwise does nothing.

Specified by:

maybeThrowError in interface ChunkSource

Throws:

IOException - The underlying error.

prepare

public boolean prepare()

Description copied from interface: ChunkSource

Prepares the source.

The method can be called repeatedly until the return value indicates success.

Specified by:

prepare in interface ChunkSource

Returns:

True if the source was prepared, false otherwise.

getTrackCount

public int getTrackCount()

Description copied from interface: ChunkSource

Returns the number of tracks exposed by the source.

This method should only be called after the source has been prepared.

Specified by:

getTrackCount in interface ChunkSource

Returns:

The number of tracks.

getFormat

public final MediaFormat getFormat(int track)

Description copied from interface: ChunkSource

Gets the format of the specified track.

This method should only be called after the source has been prepared.

Specified by:

getFormat in interface ChunkSource

Parameters:

track - The track index.

Returns:

The format of the track.

enable

public void enable(int track)

Description copied from interface: ChunkSource

Enable the source for the specified track.

This method should only be called after the source has been prepared, and when the source is disabled.

Specified by:

enable in interface ChunkSource

Parameters:

track - The track index.

continueBuffering

public void continueBuffering(long playbackPositionUs)

Description copied from interface: ChunkSource

Indicates to the source that it should still be checking for updates to the stream.

This method should only be called when the source is enabled.

Specified by:

continueBuffering in interface ChunkSource

Parameters:

playbackPositionUs - The current playback position.

getChunkOperation

public final void getChunkOperation(List<? extends MediaChunk> queue,
                                    long playbackPositionUs,
                                    ChunkOperationHolder out)

Description copied from interface: ChunkSource

Updates the provided ChunkOperationHolder to contain the next operation that should be performed by the calling ChunkSampleSource.

This method should only be called when the source is enabled.

Specified by:

getChunkOperation in interface ChunkSource

Parameters:

queue - A representation of the currently buffered MediaChunks.

playbackPositionUs - The current playback position. If the queue is empty then this parameter is the position from which playback is expected to start (or restart) and hence should be interpreted as a seek position.

out - A holder for the next operation, whose ChunkOperationHolder.endOfStream is initially set to false, whose ChunkOperationHolder.queueSize is initially equal to the length of the queue, and whose ChunkOperationHolder.chunk is initially equal to null or a Chunk previously supplied by the ChunkSource that the caller has not yet finished loading. In the latter case the chunk can either be replaced or left unchanged. Note that leaving the chunk unchanged is both preferred and more efficient than replacing it with a new but identical chunk.

onChunkLoadCompleted

public void onChunkLoadCompleted(Chunk chunk)

Description copied from interface: ChunkSource

Invoked when the ChunkSampleSource has finished loading a chunk obtained from this source.

This method should only be called when the source is enabled.

Specified by:

onChunkLoadCompleted in interface ChunkSource

Parameters:

chunk - The chunk whose load has been completed.

onChunkLoadError

public void onChunkLoadError(Chunk chunk,
                             Exception e)

Description copied from interface: ChunkSource

Invoked when the ChunkSampleSource encounters an error loading a chunk obtained from this source.

This method should only be called when the source is enabled.

Specified by:

onChunkLoadError in interface ChunkSource

Parameters:

chunk - The chunk whose load encountered the error.

e - The error.

disable

public void disable(List<? extends MediaChunk> queue)

Description copied from interface: ChunkSource

Disables the source.

This method should only be called when the source is enabled.

Specified by:

disable in interface ChunkSource

Parameters:

queue - A representation of the currently buffered MediaChunks.

adaptiveTrack

public void adaptiveTrack(MediaPresentationDescription manifest,
                          int periodIndex,
                          int adaptationSetIndex,
                          int[] representationIndices)

Description copied from interface: DashTrackSelector.Output

Outputs an adaptive track, covering the specified representations in the specified adaptation set.

Specified by:

adaptiveTrack in interface DashTrackSelector.Output

Parameters:

manifest - The media presentation description being processed.

periodIndex - The index of the period being processed.

adaptationSetIndex - The index of the adaptation set within which the representations are located.

representationIndices - The indices of the track within the element.

fixedTrack

public void fixedTrack(MediaPresentationDescription manifest,
                       int periodIndex,
                       int adaptationSetIndex,
                       int representationIndex)

Description copied from interface: DashTrackSelector.Output

Outputs an fixed track corresponding to the specified representation in the specified adaptation set.

Specified by:

fixedTrack in interface DashTrackSelector.Output

Parameters:

manifest - The media presentation description being processed.

periodIndex - The index of the period being processed.

adaptationSetIndex - The index of the adaptation set within which the track is located.

representationIndex - The index of the representation within the adaptation set.

newMediaChunk

protected Chunk newMediaChunk(DashChunkSource.PeriodHolder periodHolder,
                              DashChunkSource.RepresentationHolder representationHolder,
                              DataSource dataSource,
                              MediaFormat mediaFormat,
                              DashChunkSource.ExposedTrack enabledTrack,
                              int segmentNum,
                              int trigger,
                              boolean isMediaFormatFinal)