Renderer

Artifact: androidx.media3:media3-exoplayer

Kotlin |Java

@UnstableApi
public interface Renderer extends PlayerMessage.Target

Known direct subclasses

BaseRenderer, ForwardingRenderer, NoSampleRenderer

`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, CapturingRenderersFactory.CapturingMediaCodecVideoRenderer, DecoderAudioRenderer, DecoderVideoRenderer, FakeAudioRenderer, FakeMediaClockRenderer, FakeRenderer, FakeVideoRenderer, ImageRenderer, MediaCodecAudioRenderer, MediaCodecRenderer, MediaCodecVideoRenderer, MetadataRenderer, TextRenderer

`CameraMotionRenderer`	A `Renderer` that parses the camera motion track.
`CapturingRenderersFactory.CapturingMediaCodecVideoRenderer`	A `MediaCodecVideoRenderer` that will not skip or drop buffers due to slow processing.
`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_DURATION_TO_PROGRESS_US = 10000` Default minimum duration that the playback clock must advance before `render` can make progress.
`default static final long`	`DEFAULT_IDLE_DURATION_TO_PROGRESS_US = 1000000` Default duration to progress reported if the renderer does not need calls to `render` to progress, if it's in `STATE_ENABLED` and already `ready` or `ended`.
`default static final int`	`MSG_CUSTOM_BASE = 10000` Applications or extensions may define custom `MSG_*` constants that can be passed to renderers.
`default static final int`	`MSG_SET_AUDIO_ATTRIBUTES = 3` A type of a message that can be passed to an audio renderer via `createMessage`.
`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`.
`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`.
`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`.
`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`.
`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.
`default static final int`	`MSG_SET_PREFERRED_AUDIO_DEVICE = 12` The type of a message that can be passed to audio renderers via `createMessage`.
`default static final int`	`MSG_SET_PRIORITY = 16` The type of message that can be passed to a renderer to set its priority.
`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`.
`default static final int`	`MSG_SET_SCRUBBING_MODE = 18` The type of message that can be passed to a renderer to direct it to enable or disable scrubbing mode.
`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`.
`default static final int`	`MSG_SET_VIDEO_EFFECTS = 13` The type of a message that can be passed to a video renderer.
`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`.
`default static final int`	`MSG_SET_VIDEO_OUTPUT = 1` The type of a message that can be passed to a video renderer via `createMessage`.
`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.
`default static final int`	`MSG_SET_VOLUME = 2` A type of a message that can be passed to an audio renderer via `createMessage`.
`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.
`default static final int`	`MSG_TRANSFER_RESOURCES = 17` The type of message that can be passed to a renderer to direct it to transfer relevant resources to another renderer.
`default static final int`	`STATE_DISABLED = 0` The renderer is disabled.
`default static final int`	`STATE_ENABLED = 1` The renderer is enabled but not started.
`default static final int`	`STATE_STARTED = 2` The renderer is started.

Public methods
`abstract void`	`disable()` 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`	`enableMayRenderStartOfStream()` Enables this renderer to render the start of the stream even if the state is not `STATE_STARTED` yet.
`abstract RendererCapabilities`	`getCapabilities()` 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`	`getMediaClock()` If the renderer advances its own playback position then this method returns a corresponding `MediaClock`.
`abstract String`	`getName()` Returns the name of this renderer, for logging and debugging purposes.
`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.
`abstract int`	`@Renderer.State getState()` Returns the current state of the renderer.
`abstract @Nullable SampleStream`	`getStream()` Returns the `SampleStream` being consumed, or null if the renderer is disabled.
`abstract int`	`@C.TrackType getTrackType()` Returns the track type that the renderer handles.
`abstract boolean`	`hasReadStreamToEnd()` 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`	`isCurrentStreamFinal()` Returns whether the current `SampleStream` will be the final one supplied before the renderer is next disabled or reset.
`abstract boolean`	`isEnded()` Whether the renderer is ready for the `ExoPlayer` instance to transition to `STATE_ENDED`.
`abstract boolean`	`isReady()` Whether the renderer is able to immediately render media from the current position.
`abstract void`	`maybeThrowStreamError()` Throws an error that's preventing the renderer from reading from its `SampleStream`.
`default void`	`release()` 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`	`reset()` 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`	`setCurrentStreamFinal()` 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`	`setTimeline(Timeline timeline)` Sets the timeline that is currently being played.
`abstract void`	`start()` Starts the renderer, meaning that calls to `render` will cause media to be rendered.
`abstract void`	`stop()` 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`

DEFAULT_IDLE_DURATION_TO_PROGRESS_US

default static final long DEFAULT_IDLE_DURATION_TO_PROGRESS_US = 1000000

Default duration to progress reported if the renderer does not need calls to render to progress, if it's in STATE_ENABLED and already ready or ended.

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.

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.

Renderer

Format support

Resource management

Configuration changes

Reading and rendering samples

Timestamps and offsets

Summary

Nested types

Constants

Public methods

Inherited methods

Constants

DEFAULT_DURATION_TO_PROGRESS_US

DEFAULT_IDLE_DURATION_TO_PROGRESS_US

MSG_CUSTOM_BASE

MSG_SET_AUDIO_ATTRIBUTES

MSG_SET_AUDIO_SESSION_ID

MSG_SET_AUX_EFFECT_INFO

MSG_SET_CAMERA_MOTION_LISTENER

MSG_SET_CHANGE_FRAME_RATE_STRATEGY