com.google.android.exoplayer2.audio

Interface AudioProcessor

All Known Implementing Classes:

SilenceSkippingAudioProcessor, SonicAudioProcessor, TeeAudioProcessor

public interface AudioProcessor

Interface for audio processors, which take audio data as input and transform it, potentially modifying its channel count, encoding and/or sample rate.

Call configure(int, int, int) to configure the processor to receive input audio, then call isActive() to determine whether the processor is active. queueInput(ByteBuffer), queueEndOfStream(), getOutput(), isEnded(), getOutputChannelCount(), getOutputEncoding() and getOutputSampleRateHz() may only be called if the processor is active. Call reset() to reset the processor to its unconfigured state and release any resources.

In addition to being able to modify the format of audio, implementations may allow parameters to be set that affect the output audio and whether the processor is active/inactive.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	AudioProcessor.UnhandledFormatException Exception thrown when a processor can't be configured for a given input audio format.

Field Summary

Fields

Modifier and Type	Field and Description
static java.nio.ByteBuffer	EMPTY_BUFFER An empty, direct ByteBuffer.

Method Summary

Modifier and Type	Method and Description
boolean	configure(int sampleRateHz, int channelCount, int encoding) Configures the processor to process input audio with the specified format and returns whether to flush() it.
void	flush() Clears any state in preparation for receiving a new stream of input buffers.
java.nio.ByteBuffer	getOutput() Returns a buffer containing processed output data between its position and limit.
int	getOutputChannelCount() Returns the number of audio channels in the data output by the processor.
int	getOutputEncoding() Returns the audio encoding used in the data output by the processor.
int	getOutputSampleRateHz() Returns the sample rate of audio output by the processor, in hertz.
boolean	isActive() Returns whether the processor is configured and will process input buffers.
boolean	isEnded() Returns whether this processor will return no more output from getOutput() until it has been flush()ed and more input has been queued.
void	queueEndOfStream() Queues an end of stream signal.
void	queueInput(java.nio.ByteBuffer buffer) Queues audio data between the position and limit of the input buffer for processing.
void	reset() Resets the processor to its unconfigured state.

Field Detail

EMPTY_BUFFER

static final java.nio.ByteBuffer EMPTY_BUFFER

An empty, direct ByteBuffer.

Method Detail

configure

boolean configure(int sampleRateHz,
                  int channelCount,
                  @C.Encoding
                  int encoding)
           throws AudioProcessor.UnhandledFormatException

Configures the processor to process input audio with the specified format and returns whether to flush() it. After calling this method, if the processor is active, getOutputSampleRateHz(), getOutputChannelCount() and getOutputEncoding() return its output format.

Parameters:

sampleRateHz - The sample rate of input audio in Hz.

channelCount - The number of interleaved channels in input audio.

encoding - The encoding of input audio.

Returns:

Whether to flush() the processor.

Throws:

AudioProcessor.UnhandledFormatException - Thrown if the specified format can't be handled as input.

isActive

boolean isActive()

Returns whether the processor is configured and will process input buffers.

getOutputChannelCount

int getOutputChannelCount()

Returns the number of audio channels in the data output by the processor. The value may change as a result of calling configure(int, int, int) and is undefined if the instance is not active.

getOutputEncoding

@C.Encoding
int getOutputEncoding()

Returns the audio encoding used in the data output by the processor. The value may change as a result of calling configure(int, int, int) and is undefined if the instance is not active.

getOutputSampleRateHz

int getOutputSampleRateHz()

Returns the sample rate of audio output by the processor, in hertz. The value may change as a result of calling configure(int, int, int) and is undefined if the instance is not active.

queueInput

void queueInput(java.nio.ByteBuffer buffer)

Queues audio data between the position and limit of the input buffer for processing. buffer must be a direct byte buffer with native byte order. Its contents are treated as read-only. Its position will be advanced by the number of bytes consumed (which may be zero). The caller retains ownership of the provided buffer. Calling this method invalidates any previous buffer returned by getOutput().

Parameters:

buffer - The input buffer to process.

queueEndOfStream

void queueEndOfStream()

Queues an end of stream signal. After this method has been called, queueInput(ByteBuffer) may not be called until after the next call to flush(). Calling getOutput() will return any remaining output data. Multiple calls may be required to read all of the remaining output data. isEnded() will return true once all remaining output data has been read.

getOutput

java.nio.ByteBuffer getOutput()

Returns a buffer containing processed output data between its position and limit. The buffer will always be a direct byte buffer with native byte order. Calling this method invalidates any previously returned buffer. The buffer will be empty if no output is available.

Returns:

A buffer containing processed output data between its position and limit.

isEnded

boolean isEnded()

Returns whether this processor will return no more output from getOutput() until it has been flush()ed and more input has been queued.

flush

void flush()

Clears any state in preparation for receiving a new stream of input buffers.

reset

void reset()

Resets the processor to its unconfigured state.