com.google.android.exoplayer.text

Class TextTrackRenderer

java.lang.Object

com.google.android.exoplayer.TrackRenderer

com.google.android.exoplayer.SampleSourceTrackRenderer

com.google.android.exoplayer.text.TextTrackRenderer

All Implemented Interfaces:

Handler.Callback, ExoPlayer.ExoPlayerComponent

public final class TextTrackRenderer
extends SampleSourceTrackRenderer
implements Handler.Callback

A TrackRenderer for subtitles. Text is parsed from sample data using a SubtitleParser. The actual rendering of each line of text is delegated to a TextRenderer.

If no SubtitleParser instances are passed to the constructor, the subtitle type will be detected automatically for the following supported formats:

• WebVTT (WebvttParser)
• TTML (TtmlParser)
• SubRip (SubripParser)
• TX3G (Tx3gParser)

To override the default parsers, pass one or more SubtitleParser instances to the constructor. The first SubtitleParser that returns true from SubtitleParser.canParse(String) will be used.

Field Summary

Fields inherited from class com.google.android.exoplayer.TrackRenderer

END_OF_TRACK_US, MATCH_LONGEST_US, STATE_ENABLED, STATE_PREPARED, STATE_RELEASED, STATE_STARTED, STATE_UNPREPARED, UNKNOWN_TIME_US

Constructor Summary

Constructors

Constructor and Description
TextTrackRenderer(SampleSource[] sources, TextRenderer textRenderer, Looper textRendererLooper, SubtitleParser... subtitleParsers)
TextTrackRenderer(SampleSource source, TextRenderer textRenderer, Looper textRendererLooper, SubtitleParser... subtitleParsers)

Method Summary

Modifier and Type	Method and Description
protected void	doSomeWork(long positionUs, long elapsedRealtimeUs, boolean sourceIsReady) Called by SampleSourceTrackRenderer.doSomeWork(long, long).
protected long	getBufferedPositionUs() Returns an estimate of the absolute position in microseconds up to which data is buffered.
boolean	handleMessage(Message msg)
protected boolean	handlesTrack(MediaFormat mediaFormat) Returns whether this renderer is capable of handling the provided track.
protected boolean	isEnded() Whether the renderer is ready for the ExoPlayer instance to transition to ExoPlayer.STATE_ENDED.
protected boolean	isReady() Whether the renderer is able to immediately render media from the current position.
protected void	onDisabled() Called when the renderer is disabled.
protected void	onDiscontinuity(long positionUs) Invoked when a discontinuity is encountered.
protected void	onEnabled(int track, long positionUs, boolean joining) Called when the renderer is enabled.

Methods inherited from class com.google.android.exoplayer.SampleSourceTrackRenderer

doPrepare, doSomeWork, getDurationUs, getFormat, getTrackCount, maybeThrowError, onReleased, readSource, seekTo, shiftInputPosition

Methods inherited from class com.google.android.exoplayer.TrackRenderer

getMediaClock, getState, handleMessage, onStarted, onStopped

Methods inherited from class java.lang.Object

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

Constructor Detail

TextTrackRenderer

public TextTrackRenderer(SampleSource source,
                         TextRenderer textRenderer,
                         Looper textRendererLooper,
                         SubtitleParser... subtitleParsers)

Parameters:

source - A source from which samples containing subtitle data can be read.

textRenderer - The text renderer.

textRendererLooper - The looper associated with the thread on which textRenderer should be invoked. If the renderer makes use of standard Android UI components, then this should normally be the looper associated with the applications' main thread, which can be obtained using ContextWrapper.getMainLooper(). Null may be passed if the renderer should be invoked directly on the player's internal rendering thread.

subtitleParsers - SubtitleParsers to parse text samples, in order of decreasing priority. If omitted, the default parsers will be used.

TextTrackRenderer

public TextTrackRenderer(SampleSource[] sources,
                         TextRenderer textRenderer,
                         Looper textRendererLooper,
                         SubtitleParser... subtitleParsers)

Parameters:

sources - Sources from which samples containing subtitle data can be read.

textRenderer - The text renderer.

textRendererLooper - The looper associated with the thread on which textRenderer should be invoked. If the renderer makes use of standard Android UI components, then this should normally be the looper associated with the applications' main thread, which can be obtained using ContextWrapper.getMainLooper(). Null may be passed if the renderer should be invoked directly on the player's internal rendering thread.

subtitleParsers - SubtitleParsers to parse text samples, in order of decreasing priority. If omitted, the default parsers will be used.

Method Detail

handlesTrack

protected boolean handlesTrack(MediaFormat mediaFormat)

Description copied from class: SampleSourceTrackRenderer

Returns whether this renderer is capable of handling the provided track.

Specified by:

handlesTrack in class SampleSourceTrackRenderer

Parameters:

mediaFormat - The format of the track.

Returns:

True if the renderer can handle the track, false otherwise.

onEnabled

protected void onEnabled(int track,
                         long positionUs,
                         boolean joining)
                  throws ExoPlaybackException

Description copied from class: TrackRenderer

Called when the renderer is enabled.

The default implementation is a no-op.

Overrides:

onEnabled in class SampleSourceTrackRenderer

Parameters:

track - The track for which the renderer is being enabled.

positionUs - The player's current position.

joining - Whether this renderer is being enabled to join an ongoing playback.

Throws:

ExoPlaybackException - If an error occurs.

onDiscontinuity

protected void onDiscontinuity(long positionUs)

Description copied from class: SampleSourceTrackRenderer

Invoked when a discontinuity is encountered. Also invoked when the renderer is enabled, for convenience.

Specified by:

onDiscontinuity in class SampleSourceTrackRenderer

Parameters:

positionUs - The playback position after the discontinuity, or the position at which the renderer is being enabled.

doSomeWork

protected void doSomeWork(long positionUs,
                          long elapsedRealtimeUs,
                          boolean sourceIsReady)
                   throws ExoPlaybackException

Description copied from class: SampleSourceTrackRenderer

Called by SampleSourceTrackRenderer.doSomeWork(long, long).

Specified by:

doSomeWork in class SampleSourceTrackRenderer

Parameters:

positionUs - The current media time in microseconds, measured at the start of the current iteration of the rendering loop.

elapsedRealtimeUs - SystemClock.elapsedRealtime() in microseconds, measured at the start of the current iteration of the rendering loop.

sourceIsReady - The result of the most recent call to SampleSource.SampleSourceReader.continueBuffering(int, long).

Throws:

ExoPlaybackException - If an error occurs.

onDisabled

protected void onDisabled()
                   throws ExoPlaybackException

Description copied from class: TrackRenderer

Called when the renderer is disabled.

The default implementation is a no-op.

Overrides:

onDisabled in class SampleSourceTrackRenderer

Throws:

ExoPlaybackException - If an error occurs.

getBufferedPositionUs

protected long getBufferedPositionUs()

Description copied from class: TrackRenderer

Returns an estimate of the absolute position in microseconds up to which data is buffered.

This method may be called when the renderer is in the following states: TrackRenderer.STATE_ENABLED, TrackRenderer.STATE_STARTED

Overrides:

getBufferedPositionUs in class SampleSourceTrackRenderer

Returns:

An estimate of the absolute position in microseconds up to which data is buffered, or TrackRenderer.END_OF_TRACK_US if the track is fully buffered, or TrackRenderer.UNKNOWN_TIME_US if no estimate is available.

isEnded

protected boolean isEnded()

Description copied from class: TrackRenderer

Whether the renderer is ready for the ExoPlayer instance to transition to ExoPlayer.STATE_ENDED. The player will make this transition as soon as true is returned by all of its TrackRenderers.

This method may be called when the renderer is in the following states: TrackRenderer.STATE_ENABLED, TrackRenderer.STATE_STARTED

Specified by:

isEnded in class TrackRenderer

Returns:

Whether the renderer is ready for the player to transition to the ended state.

isReady

protected boolean isReady()

Description copied from class: TrackRenderer

Whether the renderer is able to immediately render media from the current position.

If the renderer is in the TrackRenderer.STATE_STARTED state then returning true indicates that the renderer has everything that it needs to continue playback. Returning false indicates that the player should pause until the renderer is ready.

If the renderer is in the TrackRenderer.STATE_ENABLED state then returning true indicates that the renderer is ready for playback to be started. Returning false indicates that it is not.

This method may be called when the renderer is in the following states: TrackRenderer.STATE_ENABLED, TrackRenderer.STATE_STARTED

Specified by:

isReady in class TrackRenderer

Returns:

True if the renderer is ready to render media. False otherwise.

handleMessage

public boolean handleMessage(Message msg)

Specified by:

handleMessage in interface Handler.Callback