com.google.android.exoplayer2.trackselection

Class DefaultTrackSelector

java.lang.Object

com.google.android.exoplayer2.trackselection.TrackSelector

com.google.android.exoplayer2.trackselection.MappingTrackSelector

com.google.android.exoplayer2.trackselection.DefaultTrackSelector

public class DefaultTrackSelector
extends MappingTrackSelector

A default TrackSelector suitable for most use cases.

Constraint based track selection

Whilst this selector supports setting specific track overrides, the recommended way of changing which tracks are selected is by setting DefaultTrackSelector.Parameters that constrain the track selection process. For example an instance can specify a preferred language for the audio track, and impose constraints on the maximum video resolution that should be selected for adaptive playbacks. Modifying the parameters is simple:

 
 Parameters currentParameters = trackSelector.getParameters();
 // Generate new parameters to prefer German audio and impose a maximum video size constraint.
 Parameters newParameters = currentParameters
     .withPreferredAudioLanguage("deu")
     .withMaxVideoSize(1024, 768);
 // Set the new parameters on the selector.
 trackSelector.setParameters(newParameters);
 

There are several benefits to using constraint based track selection instead of specific track overrides:

• You can specify constraints before knowing what tracks the media provides. This can simplify track selection code (e.g. you don't have to listen for changes in the available tracks before configuring the selector).
• Constraints can be applied consistently across all periods in a complex piece of media, even if those periods contain different tracks. In contrast, a specific track override is only applied to periods whose tracks match those for which the override was set.

Track overrides, disabling renderers and tunneling

This selector extends MappingTrackSelector, and so inherits its support for setting specific track overrides, disabling renderers and configuring tunneled media playback. See MappingTrackSelector for details.

Extending this class

This class is designed to be extensible by developers who wish to customize its behavior but do not wish to implement their own MappingTrackSelector or TrackSelector from scratch.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	DefaultTrackSelector.Parameters Constraint parameters for DefaultTrackSelector.
static class	DefaultTrackSelector.ParametersBuilder A builder for DefaultTrackSelector.Parameters.

Nested classes/interfaces inherited from class com.google.android.exoplayer2.trackselection.MappingTrackSelector

MappingTrackSelector.MappedTrackInfo, MappingTrackSelector.SelectionOverride

Nested classes/interfaces inherited from class com.google.android.exoplayer2.trackselection.TrackSelector

TrackSelector.InvalidationListener

Constructor Summary

Constructors

Constructor and Description
DefaultTrackSelector() Constructs an instance that does not support adaptive track selection.
DefaultTrackSelector(BandwidthMeter bandwidthMeter) Constructs an instance that supports adaptive track selection.
DefaultTrackSelector(TrackSelection.Factory adaptiveTrackSelectionFactory) Constructs an instance that uses a factory to create adaptive track selections.

Method Summary

Modifier and Type	Method and Description
protected static boolean	formatHasLanguage(Format format, java.lang.String language) Returns whether a Format specifies a particular language, or false if language is null.
protected static boolean	formatHasNoLanguage(Format format) Returns whether a Format does not define a language.
DefaultTrackSelector.Parameters	getParameters() Gets the current selection parameters.
protected static boolean	isSupported(int formatSupport, boolean allowExceedsCapabilities) Applies the RendererCapabilities.FORMAT_SUPPORT_MASK to a value obtained from RendererCapabilities.supportsFormat(Format), returning true if the result is RendererCapabilities.FORMAT_HANDLED or if allowExceedsCapabilities is set and the result is RendererCapabilities.FORMAT_EXCEEDS_CAPABILITIES.
protected TrackSelection	selectAudioTrack(TrackGroupArray groups, int[][] formatSupport, DefaultTrackSelector.Parameters params, TrackSelection.Factory adaptiveTrackSelectionFactory) Called by selectTracks(RendererCapabilities[], TrackGroupArray[], int[][][]) to create a TrackSelection for an audio renderer.
protected TrackSelection	selectOtherTrack(int trackType, TrackGroupArray groups, int[][] formatSupport, DefaultTrackSelector.Parameters params) Called by selectTracks(RendererCapabilities[], TrackGroupArray[], int[][][]) to create a TrackSelection for a renderer whose type is neither video, audio or text.
protected TrackSelection	selectTextTrack(TrackGroupArray groups, int[][] formatSupport, DefaultTrackSelector.Parameters params) Called by selectTracks(RendererCapabilities[], TrackGroupArray[], int[][][]) to create a TrackSelection for a text renderer.
protected TrackSelection[]	selectTracks(RendererCapabilities[] rendererCapabilities, TrackGroupArray[] rendererTrackGroupArrays, int[][][] rendererFormatSupports) Given an array of renderer capabilities and the TrackGroupArrays mapped to each of them, provides a TrackSelection per renderer.
protected TrackSelection	selectVideoTrack(RendererCapabilities rendererCapabilities, TrackGroupArray groups, int[][] formatSupport, DefaultTrackSelector.Parameters params, TrackSelection.Factory adaptiveTrackSelectionFactory) Called by selectTracks(RendererCapabilities[], TrackGroupArray[], int[][][]) to create a TrackSelection for a video renderer.
void	setParameters(DefaultTrackSelector.Parameters params) Atomically sets the provided parameters for track selection.

Methods inherited from class com.google.android.exoplayer2.trackselection.MappingTrackSelector

clearSelectionOverride, clearSelectionOverrides, clearSelectionOverrides, getCurrentMappedTrackInfo, getRendererDisabled, getSelectionOverride, hasSelectionOverride, onSelectionActivated, selectTracks, setRendererDisabled, setSelectionOverride, setTunnelingAudioSessionId

Methods inherited from class com.google.android.exoplayer2.trackselection.TrackSelector

init, invalidate

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultTrackSelector

public DefaultTrackSelector()

Constructs an instance that does not support adaptive track selection.

DefaultTrackSelector

public DefaultTrackSelector(BandwidthMeter bandwidthMeter)

Constructs an instance that supports adaptive track selection. Adaptive track selections use the provided BandwidthMeter to determine which individual track should be used during playback.

Parameters:

bandwidthMeter - The BandwidthMeter.

DefaultTrackSelector

public DefaultTrackSelector(TrackSelection.Factory adaptiveTrackSelectionFactory)

Constructs an instance that uses a factory to create adaptive track selections.

Parameters:

adaptiveTrackSelectionFactory - A factory for adaptive TrackSelections, or null if the selector should not support adaptive tracks.

Method Detail

setParameters

public void setParameters(DefaultTrackSelector.Parameters params)

Atomically sets the provided parameters for track selection.

Parameters:

params - The parameters for track selection.

getParameters

public DefaultTrackSelector.Parameters getParameters()

Gets the current selection parameters.

Returns:

The current selection parameters.

selectTracks

protected TrackSelection[] selectTracks(RendererCapabilities[] rendererCapabilities,
                                        TrackGroupArray[] rendererTrackGroupArrays,
                                        int[][][] rendererFormatSupports)
                                 throws ExoPlaybackException

Description copied from class: MappingTrackSelector

Given an array of renderer capabilities and the TrackGroupArrays mapped to each of them, provides a TrackSelection per renderer.

Specified by:

selectTracks in class MappingTrackSelector

Parameters:

rendererCapabilities - The RendererCapabilities of the renderers for which TrackSelections are to be generated.

rendererTrackGroupArrays - The TrackGroupArrays mapped to each of the renderers.

rendererFormatSupports - The result of RendererCapabilities.supportsFormat(com.google.android.exoplayer2.Format) for each mapped track, indexed by renderer index, track group index and track index (in that order).

Throws:

ExoPlaybackException - If an error occurs while selecting the tracks.

selectVideoTrack

protected TrackSelection selectVideoTrack(RendererCapabilities rendererCapabilities,
                                          TrackGroupArray groups,
                                          int[][] formatSupport,
                                          DefaultTrackSelector.Parameters params,
                                          TrackSelection.Factory adaptiveTrackSelectionFactory)
                                   throws ExoPlaybackException

Called by selectTracks(RendererCapabilities[], TrackGroupArray[], int[][][]) to create a TrackSelection for a video renderer.

Parameters:

rendererCapabilities - The RendererCapabilities for the renderer.

groups - The TrackGroupArray mapped to the renderer.

formatSupport - The result of RendererCapabilities.supportsFormat(com.google.android.exoplayer2.Format) for each mapped track, indexed by track group index and track index (in that order).

params - The selector's current constraint parameters.

adaptiveTrackSelectionFactory - A factory for generating adaptive track selections, or null if a fixed track selection is required.

Returns:

The TrackSelection for the renderer, or null if no selection was made.

Throws:

ExoPlaybackException - If an error occurs while selecting the tracks.

selectAudioTrack

protected TrackSelection selectAudioTrack(TrackGroupArray groups,
                                          int[][] formatSupport,
                                          DefaultTrackSelector.Parameters params,
                                          TrackSelection.Factory adaptiveTrackSelectionFactory)
                                   throws ExoPlaybackException

Called by selectTracks(RendererCapabilities[], TrackGroupArray[], int[][][]) to create a TrackSelection for an audio renderer.

Parameters:

groups - The TrackGroupArray mapped to the renderer.

formatSupport - The result of RendererCapabilities.supportsFormat(com.google.android.exoplayer2.Format) for each mapped track, indexed by track group index and track index (in that order).

params - The selector's current constraint parameters.

adaptiveTrackSelectionFactory - A factory for generating adaptive track selections, or null if a fixed track selection is required.

Returns:

The TrackSelection for the renderer, or null if no selection was made.

Throws:

ExoPlaybackException - If an error occurs while selecting the tracks.

selectTextTrack

protected TrackSelection selectTextTrack(TrackGroupArray groups,
                                         int[][] formatSupport,
                                         DefaultTrackSelector.Parameters params)
                                  throws ExoPlaybackException

Called by selectTracks(RendererCapabilities[], TrackGroupArray[], int[][][]) to create a TrackSelection for a text renderer.

Parameters:

groups - The TrackGroupArray mapped to the renderer.

formatSupport - The result of RendererCapabilities.supportsFormat(com.google.android.exoplayer2.Format) for each mapped track, indexed by track group index and track index (in that order).

params - The selector's current constraint parameters.

Returns:

The TrackSelection for the renderer, or null if no selection was made.

Throws:

ExoPlaybackException - If an error occurs while selecting the tracks.

selectOtherTrack

protected TrackSelection selectOtherTrack(int trackType,
                                          TrackGroupArray groups,
                                          int[][] formatSupport,
                                          DefaultTrackSelector.Parameters params)
                                   throws ExoPlaybackException

Called by selectTracks(RendererCapabilities[], TrackGroupArray[], int[][][]) to create a TrackSelection for a renderer whose type is neither video, audio or text.

Parameters:

trackType - The type of the renderer.

groups - The TrackGroupArray mapped to the renderer.

formatSupport - The result of RendererCapabilities.supportsFormat(com.google.android.exoplayer2.Format) for each mapped track, indexed by track group index and track index (in that order).

params - The selector's current constraint parameters.

Returns:

The TrackSelection for the renderer, or null if no selection was made.

Throws:

ExoPlaybackException - If an error occurs while selecting the tracks.

isSupported

protected static boolean isSupported(int formatSupport,
                                     boolean allowExceedsCapabilities)

Applies the RendererCapabilities.FORMAT_SUPPORT_MASK to a value obtained from RendererCapabilities.supportsFormat(Format), returning true if the result is RendererCapabilities.FORMAT_HANDLED or if allowExceedsCapabilities is set and the result is RendererCapabilities.FORMAT_EXCEEDS_CAPABILITIES.

Parameters:

formatSupport - A value obtained from RendererCapabilities.supportsFormat(Format).

allowExceedsCapabilities - Whether to return true if the format support component of the value is RendererCapabilities.FORMAT_EXCEEDS_CAPABILITIES.

Returns:

True if the format support component is RendererCapabilities.FORMAT_HANDLED, or if allowExceedsCapabilities is set and the format support component is RendererCapabilities.FORMAT_EXCEEDS_CAPABILITIES.

formatHasNoLanguage

protected static boolean formatHasNoLanguage(Format format)

Returns whether a Format does not define a language.

Parameters:

format - The Format.

Returns:

Whether the Format does not define a language.

formatHasLanguage

protected static boolean formatHasLanguage(Format format,
                                           java.lang.String language)

Returns whether a Format specifies a particular language, or false if language is null.

Parameters:

format - The Format.

language - The language.

Returns:

Whether the format specifies the language, or false if language is null.