@UnstableApi
public interface Renderer extends PlayerMessage.Target

Known direct subclasses
BaseRenderer

An abstract base class suitable for most Renderer implementations.
ForwardingRenderer

An overridable Renderer implementation forwarding all methods to another renderer.
NoSampleRenderer

A Renderer implementation whose track type is TRACK_TYPE_NONE and does not consume data from its SampleStream.
Known indirect subclasses
CameraMotionRenderer

A Renderer that parses the camera motion track.
DecoderAudioRenderer

Decodes and renders audio using a Decoder.
DecoderVideoRenderer

Decodes and renders video using a Decoder.
FakeAudioRenderer

A FakeRenderer that supports TRACK_TYPE_AUDIO.
FakeMediaClockRenderer

Fake abstract Renderer which is also a MediaClock.
FakeRenderer

Fake Renderer that supports any format with the matching track type.
FakeVideoRenderer

A FakeRenderer that supports TRACK_TYPE_VIDEO.
ImageRenderer

A Renderer implementation for images.
MediaCodecAudioRenderer

Decodes and renders audio using MediaCodec and an AudioSink.
MediaCodecRenderer

An abstract renderer that uses MediaCodec to decode samples for rendering.
MediaCodecVideoRenderer

Decodes and renders video using MediaCodec.
MetadataRenderer

A renderer for metadata.
TextRenderer

A Renderer for text.

Renders media read from a SampleStream.

Internally, a renderer's lifecycle is managed by the owning ExoPlayer. The renderer is transitioned through various states as the overall playback state and enabled tracks change. The valid state transitions are shown below, annotated with the methods that are called during each transition.

Renderer state transitions

Format support

The player will select a renderer based on the RendererCapabilities returned from getCapabilities. If the capabilities indicate support for a Format, the renderer is expected to handle SampleStream instances containing samples of this Format.

Resource management

Renderers should acquire resources like codecs when entering STATE_ENABLED for the first time. As the renderer may transition quickly to and from STATE_DISABLED, it is recommended to hold onto resources even when entering STATE_DISABLED. The player will explicitly call reset if the renderer is no longer needed, at which point any acquired limited resources should be released.

Configuration changes

As renderers are created once in the lifetime of a player, they may need to be re-configured later based on user settings or other environmental changes. This is generally done by handling player messages in handleMessage. There are many predefined common reconfigurations in MessageType, but custom renderers can add their own handling as needed.

Reading and rendering samples

The renderer receives a SampleStream to read from when enabled. When seamlessly transitioning from one item to another, the renderer may get new instances via replaceStream. Note that replaceStream may be called as soon as the end-of-stream signal has been read from the current SampleStream to allow reading new samples as early as possible. At this point, the renderer may still be processing samples from the previous stream(s). Once the current stream has been marked as final, no further calls to replaceStream are allowed to happen without first disabling the renderer again.

The player will regularly call render to let the renderer make progress. Once the renderer has prepared its internal pipeline to handle continuous playback progress, it should report itself as isReady. The player will only transition the renderer to STATE_STARTED if it reports itself as ready. If the renderer is blocked from making progress, it should return false from isReady, which will result in a stop operation back to STATE_ENABLED.

As long as it is in STATE_STARTED, the renderer is expected to actively output the data it is processing in line with the current playback position passed to render. The only exception is the very first sample (for example the first video frame), that is allowed to be output in STATE_ENABLED if the mayRenderStartOfStream flag was set in enable or later set via enableMayRenderStartOfStream.

Once the renderer finished all processing it needs to do (that is, no further call to render is needed) and the current stream is final, it should report itself as isEnded.

Timestamps and offsets

The renderer deals with potentially multiple consecutive input streams and has to handle position updates and stream transitions. This means there are multiple types of timestamps and offsets relevant in the context of this class:

  • SampleStream timestamp: The timestamp associated with each sample read from a SampleStream. This corresponds to the time in the Timeline.Period this stream belongs to. The current playback context can be obtained by using the Timeline and the MediaPeriodId provided together with each .
  • Renderer timestamp: The timestamp of the overall playback. This is a continuously increasing value across all input sample streams and what it passed to render as the current positionUs.
  • Stream offset: The constant offset between the current SampleStream timestamps and the renderer timestamp. This value is provided when setting a new stream in enable or replaceStream.
  • Stream start position: The renderer timestamp at which the current first starts playing. This value is provided when setting a new stream in enable or replaceStream. Note that it may be different from the Stream offset as streams can start at non-zero SampleStream timestamps.
  • Reset position: The Renderer timestamp at which continuous playback last started. This is either the stream start position provided in enable, or the position set in any subsequent resetPosition call. Note that this value is not changed when playback transitions seamlessly to a new stream after calling replaceStream. After any position reset, the samples read next are those needed to start playback at the intended reset position. In some cases, the renderer will encounter output data before the intended reset position (for example video frames starting from the previous keyframe). In these cases, the renderer should drop data internally and only start producing output at the intended reset position.

Summary

Nested types
@Documented
@Retention(value = RetentionPolicy.SOURCE)
@Target(value = TYPE_USE)
@IntDef(open = true, value = )
public annotation Renderer.MessageType

Represents a type of message that can be passed to a renderer.
@Documented
@Retention(value = RetentionPolicy.SOURCE)
@Target(value = TYPE_USE)
@IntDef(value = )
public annotation Renderer.State

The renderer states.
public interface Renderer.WakeupListener

Some renderers can signal when render should be called.

Constants
default static final long

Default minimum duration that the playback clock must advance before render can make progress.
default static final int

Applications or extensions may define custom MSG_* constants that can be passed to renderers.
default static final int

A type of a message that can be passed to an audio renderer via createMessage.
default static final int

The type of a message that can be passed to audio and video renderers via createMessage.
default static final int

A type of a message that can be passed to an audio renderer via createMessage.
default static final int

The type of a message that can be passed to a camera motion renderer via createMessage.
default static final int

The type of a message that can be passed to a video renderer via createMessage.
default static final int

The type of message that can be passed to an image renderer to set a desired image output.
default static final int

The type of a message that can be passed to audio renderers via createMessage.
default static final int

The type of message that can be passed to a renderer to set its priority.
default static final int

The type of a message that can be passed to a MediaCodec-based video renderer via createMessage.
default static final int

The type of a message that can be passed to an audio renderer via createMessage.
default static final int

The type of a message that can be passed to a video renderer.
default static final int

The type of a message that can be passed to a video renderer via createMessage.
default static final int

The type of a message that can be passed to a video renderer via createMessage.
default static final int

The type of a message that can be passed to a video renderer to set the desired output resolution.
default static final int

A type of a message that can be passed to an audio renderer via createMessage.
default static final int

The type of a message that can be passed to a Renderer via createMessage, to inform the renderer that it can schedule waking up another component.
default static final int

The renderer is disabled.
default static final int

The renderer is enabled but not started.
default static final int

The renderer is started.

Public methods
abstract void

Disable the renderer, transitioning it to the STATE_DISABLED state.
abstract void
enable(
    RendererConfiguration configuration,
    Format[] formats,
    SampleStream stream,
    long positionUs,
    boolean joining,
    boolean mayRenderStartOfStream,
    long startPositionUs,
    long offsetUs,
    MediaSource.MediaPeriodId mediaPeriodId
)

Enables the renderer to consume from the specified SampleStream.
default void

Enables this renderer to render the start of the stream even if the state is not STATE_STARTED yet.
abstract RendererCapabilities

Returns the capabilities of the renderer.
default long
getDurationToProgressUs(long positionUs, long elapsedRealtimeUs)

Returns minimum amount of playback clock time that must pass in order for the render call to make progress.
abstract @Nullable MediaClock

If the renderer advances its own playback position then this method returns a corresponding MediaClock.
abstract String

Returns the name of this renderer, for logging and debugging purposes.
abstract long

Returns the renderer time up to which the renderer has read samples, in microseconds, or TIME_END_OF_SOURCE if the renderer has read the current SampleStream to the end.
abstract int

Returns the current state of the renderer.
abstract @Nullable SampleStream

Returns the SampleStream being consumed, or null if the renderer is disabled.
abstract int

Returns the track type that the renderer handles.
abstract boolean

Returns whether the renderer has read the current SampleStream to the end.
abstract void
init(int index, PlayerId playerId, Clock clock)

Initializes the renderer for playback with a player.
abstract boolean

Returns whether the current SampleStream will be the final one supplied before the renderer is next disabled or reset.
abstract boolean

Whether the renderer is ready for the ExoPlayer instance to transition to STATE_ENDED.
abstract boolean

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

Throws an error that's preventing the renderer from reading from its SampleStream.
default void

Releases the renderer.
abstract void
render(long positionUs, long elapsedRealtimeUs)

Incrementally renders the SampleStream.
abstract void
replaceStream(
    Format[] formats,
    SampleStream stream,
    long startPositionUs,
    long offsetUs,
    MediaSource.MediaPeriodId mediaPeriodId
)

Replaces the SampleStream from which samples will be consumed.
abstract void

Forces the renderer to give up any resources (e.g. media decoders) that it may be holding.
abstract void
resetPosition(long positionUs)

Signals to the renderer that a position discontinuity has occurred.
abstract void

Signals to the renderer that the current SampleStream will be the final one supplied before it is next disabled or reset.
default void
setPlaybackSpeed(float currentPlaybackSpeed, float targetPlaybackSpeed)

Indicates the playback speed to this renderer.
abstract void

Sets the timeline that is currently being played.
abstract void

Starts the renderer, meaning that calls to render will cause media to be rendered.
abstract void

Stops the renderer, transitioning it to the STATE_ENABLED state.

Inherited methods
From androidx.media3.exoplayer.PlayerMessage.Target
abstract void
handleMessage(
    @Renderer.MessageType int messageType,
    @Nullable Object message
)

Handles a message delivered to the target.

Constants

DEFAULT_DURATION_TO_PROGRESS_US

default static final long DEFAULT_DURATION_TO_PROGRESS_US = 10000

Default minimum duration that the playback clock must advance before render can make progress.

See also
getDurationToProgressUs

MSG_CUSTOM_BASE

default static final int MSG_CUSTOM_BASE = 10000

Applications or extensions may define custom MSG_* constants that can be passed to renderers. These custom constants must be greater than or equal to this value.

MSG_SET_AUDIO_ATTRIBUTES

default static final int MSG_SET_AUDIO_ATTRIBUTES = 3

A type of a message that can be passed to an audio renderer via createMessage. The message payload should be an instance that will configure the underlying audio track. If not set, the default audio attributes will be used. They are suitable for general media playback.

Setting the audio attributes during playback may introduce a short gap in audio output as the audio track is recreated. A new audio session id will also be generated.

If tunneling is enabled by the track selector, the specified audio attributes will be ignored, but they will take effect if audio is later played without tunneling.

If the device is running a build before platform API version 21, audio attributes cannot be set directly on the underlying audio track. In this case, the usage will be mapped onto an equivalent stream type using getStreamTypeForAudioUsage.

To get audio attributes that are equivalent to a legacy stream type, pass the stream type to getAudioUsageForStreamType and use the returned C.AudioUsage to build an audio attributes instance.

MSG_SET_AUDIO_SESSION_ID

default static final int MSG_SET_AUDIO_SESSION_ID = 10

The type of a message that can be passed to audio and video renderers via createMessage. The message payload should be an instance representing the audio session ID that will be attached to the underlying audio track. Video renderers that support tunneling will use the audio session ID when tunneling is enabled.

MSG_SET_AUX_EFFECT_INFO

default static final int MSG_SET_AUX_EFFECT_INFO = 6

A type of a message that can be passed to an audio renderer via createMessage. The message payload should be an instance representing an auxiliary audio effect for the underlying audio track.

MSG_SET_CAMERA_MOTION_LISTENER

default static final int MSG_SET_CAMERA_MOTION_LISTENER = 8

The type of a message that can be passed to a camera motion renderer via createMessage. The message payload should be a instance, or null.

MSG_SET_CHANGE_FRAME_RATE_STRATEGY

default static final int MSG_SET_CHANGE_FRAME_RATE_STRATEGY = 5

The type of a message that can be passed to a video renderer via createMessage. The message payload should be one of the integer strategy constants in C.VideoChangeFrameRateStrategy.

MSG_SET_IMAGE_OUTPUT

default static final int MSG_SET_IMAGE_OUTPUT = 15

The type of message that can be passed to an image renderer to set a desired image output. The message payload should be an ImageOutput, or null to clear a previously set image output.

MSG_SET_PREFERRED_AUDIO_DEVICE

default static final int MSG_SET_PREFERRED_AUDIO_DEVICE = 12

The type of a message that can be passed to audio renderers via createMessage. The message payload should be an instance representing the preferred audio device, or null to restore the default.

MSG_SET_PRIORITY

default static final int MSG_SET_PRIORITY = 16

The type of message that can be passed to a renderer to set its priority. The message payload should be an Integer instance for the priority of the renderer. See C.PRIORITY_ constants for predefined values.

MSG_SET_SCALING_MODE

default static final int MSG_SET_SCALING_MODE = 4

The type of a message that can be passed to a MediaCodec-based video renderer via createMessage. The message payload should be one of the integer scaling modes in C.VideoScalingMode.

Note that the scaling mode only applies if the Surface targeted by the renderer is owned by a android.view.SurfaceView.

MSG_SET_SKIP_SILENCE_ENABLED

default static final int MSG_SET_SKIP_SILENCE_ENABLED = 9

The type of a message that can be passed to an audio renderer via createMessage. The message payload should be a Boolean instance telling whether to enable or disable skipping silences in the audio stream.

MSG_SET_VIDEO_EFFECTS

default static final int MSG_SET_VIDEO_EFFECTS = 13

The type of a message that can be passed to a video renderer. The message payload should be a List containing video effects.

MSG_SET_VIDEO_FRAME_METADATA_LISTENER

default static final int MSG_SET_VIDEO_FRAME_METADATA_LISTENER = 7

The type of a message that can be passed to a video renderer via createMessage. The message payload should be a instance, or null.

MSG_SET_VIDEO_OUTPUT

default static final int MSG_SET_VIDEO_OUTPUT = 1

The type of a message that can be passed to a video renderer via createMessage. The message payload is normally a , however some video renderers may accept other outputs (e.g., ).

If the receiving renderer does not support the payload type as an output, then it will clear any existing output that it has.

MSG_SET_VIDEO_OUTPUT_RESOLUTION

default static final int MSG_SET_VIDEO_OUTPUT_RESOLUTION = 14

The type of a message that can be passed to a video renderer to set the desired output resolution. The message payload should be a Size of the desired output width and height. Use this method only when playing with video effects.

MSG_SET_VOLUME

default static final int MSG_SET_VOLUME = 2

A type of a message that can be passed to an audio renderer via createMessage. The message payload should be a Float with 0 being silence and 1 being unity gain.

MSG_SET_WAKEUP_LISTENER

default static final int MSG_SET_WAKEUP_LISTENER = 11

The type of a message that can be passed to a Renderer via createMessage, to inform the renderer that it can schedule waking up another component.

The message payload must be a WakeupListener instance.

STATE_DISABLED

default static final int STATE_DISABLED = 0

The renderer is disabled. A renderer in this state will not proactively acquire resources that it requires for rendering (e.g., media decoders), but may continue to hold any that it already has. reset can be called to force the renderer to release such resources.

STATE_ENABLED

default static final int STATE_ENABLED = 1

The renderer is enabled but not started. A renderer in this state may render media at the current position (e.g. an initial video frame), but the position will not advance. A renderer in this state will typically hold resources that it requires for rendering (e.g. media decoders).

STATE_STARTED

default static final int STATE_STARTED = 2

The renderer is started. Calls to render will cause media to be rendered.

Public methods

disable

abstract void disable()

Disable the renderer, transitioning it to the STATE_DISABLED state.

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

enable

abstract void enable(
    RendererConfiguration configuration,
    Format[] formats,
    SampleStream stream,
    long positionUs,
    boolean joining,
    boolean mayRenderStartOfStream,
    long startPositionUs,
    long offsetUs,
    MediaSource.MediaPeriodId mediaPeriodId
)

Enables the renderer to consume from the specified SampleStream.

This method may be called when the renderer is in the following states: STATE_DISABLED.

Parameters
RendererConfiguration configuration

The renderer configuration.
Format[] formats

The enabled formats.
SampleStream stream

The SampleStream from which the renderer should consume.
long positionUs

The player's current position.
boolean joining

Whether this renderer is being enabled to join an ongoing playback.
boolean mayRenderStartOfStream

Whether this renderer is allowed to render the start of the stream even if the state is not STATE_STARTED yet.
long startPositionUs

The start position of the stream in renderer time (microseconds).
long offsetUs

The offset to be added to timestamps of buffers read from stream before they are rendered.
MediaSource.MediaPeriodId mediaPeriodId

The MediaPeriodId of the MediaPeriod producing the stream.
Throws
androidx.media3.exoplayer.ExoPlaybackException

If an error occurs.

enableMayRenderStartOfStream

default void enableMayRenderStartOfStream()

Enables this renderer to render the start of the stream even if the state is not STATE_STARTED yet.

This is used to update the value of mayRenderStartOfStream passed to enable.

getCapabilities

abstract RendererCapabilities getCapabilities()

Returns the capabilities of the renderer.

Returns
RendererCapabilities

The capabilities of the renderer.

getDurationToProgressUs

default long getDurationToProgressUs(long positionUs, long elapsedRealtimeUs)

Returns minimum amount of playback clock time that must pass in order for the render call to make progress.

The default return time is DEFAULT_DURATION_TO_PROGRESS_US.

Parameters
long positionUs

The current render position in microseconds, measured at the start of the current iteration of the rendering loop.
long elapsedRealtimeUs

elapsedRealtime in microseconds, measured at the start of the current iteration of the rendering loop.
Returns
long

Minimum amount of playback clock time that must pass before renderer is able to make progress.

getMediaClock

abstract @Nullable MediaClock getMediaClock()

If the renderer advances its own playback position then this method returns a corresponding MediaClock. If provided, the player will use the returned MediaClock as its source of time during playback. A player may have at most one renderer that returns a from this method.

Returns
@Nullable MediaClock

The MediaClock tracking the playback position of the renderer, or null.

getName

abstract String getName()

Returns the name of this renderer, for logging and debugging purposes. Should typically be the renderer's (un-obfuscated) class name.

Returns
String

The name of this renderer.

getReadingPositionUs

abstract long getReadingPositionUs()

Returns the renderer time up to which the renderer has read samples, in microseconds, or TIME_END_OF_SOURCE if the renderer has read the current SampleStream to the end.

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

getState

@Renderer.State
abstract int getState()

Returns the current state of the renderer.

Returns
int

The current state. One of STATE_DISABLED, STATE_ENABLED and STATE_STARTED.

getStream

abstract @Nullable SampleStream getStream()

Returns the SampleStream being consumed, or null if the renderer is disabled.

getTrackType

@C.TrackType
abstract int getTrackType()

Returns the track type that the renderer handles.

Returns
int

The track type.
See also
getRendererType

hasReadStreamToEnd

abstract boolean hasReadStreamToEnd()

Returns whether the renderer has read the current SampleStream to the end.

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

init

abstract void init(int index, PlayerId playerId, Clock clock)

Initializes the renderer for playback with a player.

Parameters
int index

The renderer index within the player.
PlayerId playerId

The PlayerId of the player.
Clock clock

The Clock.

isCurrentStreamFinal

abstract boolean isCurrentStreamFinal()

Returns whether the current SampleStream will be the final one supplied before the renderer is next disabled or reset.

isEnded

abstract boolean isEnded()

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

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

Returns
boolean

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

isReady

abstract boolean isReady()

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

If the renderer is in the 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 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: STATE_ENABLED, STATE_STARTED.

Returns
boolean

Whether the renderer is ready to render media.

maybeThrowStreamError

abstract void maybeThrowStreamError()

Throws an error that's preventing the renderer from reading from its SampleStream. Does nothing if no such error exists.

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

Throws
java.io.IOException

An error that's preventing the renderer from making progress or buffering more data.

release

default void release()

Releases the renderer.

The renderer must not be used after calling this method.

render

abstract void render(long positionUs, long elapsedRealtimeUs)

Incrementally renders the SampleStream.

If the renderer is in the STATE_ENABLED state then each call to this method will do work toward being ready to render the SampleStream when the renderer is started. If the renderer is in the STATE_STARTED state then calls to this method will render the SampleStream in sync with the specified media positions.

The renderer may also render the very start of the media at the current position (e.g. the first frame of a video stream) while still in the STATE_ENABLED state, unless it's the initial start of the media after calling enable with mayRenderStartOfStream set to false.

This method should return quickly, and should not block if the renderer is unable to make useful progress.

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

Parameters
long positionUs

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

elapsedRealtime in microseconds, measured at the start of the current iteration of the rendering loop.
Throws
androidx.media3.exoplayer.ExoPlaybackException

If an error occurs.

replaceStream

abstract void replaceStream(
    Format[] formats,
    SampleStream stream,
    long startPositionUs,
    long offsetUs,
    MediaSource.MediaPeriodId mediaPeriodId
)

Replaces the SampleStream from which samples will be consumed.

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

Parameters
Format[] formats

The enabled formats.
SampleStream stream

The SampleStream from which the renderer should consume.
long startPositionUs

The start position of the new stream in renderer time (microseconds).
long offsetUs

The offset to be added to timestamps of buffers read from stream before they are rendered.
MediaSource.MediaPeriodId mediaPeriodId

The MediaPeriodId of the MediaPeriod producing the stream.
Throws
androidx.media3.exoplayer.ExoPlaybackException

If an error occurs.

reset

abstract void reset()

Forces the renderer to give up any resources (e.g. media decoders) that it may be holding. If the renderer is not holding any resources, the call is a no-op.

This method may be called when the renderer is in the following states: STATE_DISABLED.

resetPosition

abstract void resetPosition(long positionUs)

Signals to the renderer that a position discontinuity has occurred.

After a position discontinuity, the renderer's SampleStream is guaranteed to provide samples starting from a key frame.

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

Parameters
long positionUs

The new playback position in microseconds.
Throws
androidx.media3.exoplayer.ExoPlaybackException

If an error occurs handling the reset.

setCurrentStreamFinal

abstract void setCurrentStreamFinal()

Signals to the renderer that the current SampleStream will be the final one supplied before it is next disabled or reset.

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

setPlaybackSpeed

default void setPlaybackSpeed(float currentPlaybackSpeed, float targetPlaybackSpeed)

Indicates the playback speed to this renderer.

The default implementation is a no-op.

Parameters
float currentPlaybackSpeed

The factor by which playback is currently sped up.
float targetPlaybackSpeed

The target factor by which playback should be sped up. This may be different from currentPlaybackSpeed, for example, if the speed is temporarily adjusted for live playback.
Throws
androidx.media3.exoplayer.ExoPlaybackException

If an error occurs handling the playback speed.

setTimeline

abstract void setTimeline(Timeline timeline)

Sets the timeline that is currently being played.

start

abstract void start()

Starts the renderer, meaning that calls to render will cause media to be rendered.

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

Throws
androidx.media3.exoplayer.ExoPlaybackException

If an error occurs.

stop

abstract void stop()

Stops the renderer, transitioning it to the STATE_ENABLED state.

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