# ChannelMixingAudioProcessor
# ChannelMixingAudioProcessor
Artifact:[androidx.media3:media3-common](https://developer.android.com/jetpack/androidx/releases/media3)
[View Source](https://cs.android.com/search?q=file:androidx/media3/common/audio/ChannelMixingAudioProcessor.java+class:androidx.media3.common.audio.ChannelMixingAudioProcessor)
*** ** * ** ***
Kotlin\|[Java](https://developer.android.com/reference/androidx/media3/common/audio/ChannelMixingAudioProcessor "View this page in Java")
```
@UnstableApi
class ChannelMixingAudioProcessor : BaseAudioProcessor
```
|---|---|---------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| [kotlin.Any](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-any/index.html) |||
| ↳ | [androidx.media3.common.audio.BaseAudioProcessor](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor) ||
| | ↳ | [androidx.media3.common.audio.ChannelMixingAudioProcessor](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/ChannelMixingAudioProcessor) |
*** ** * ** ***
An[AudioProcessor](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor)that handles mixing and scaling audio channels. Call[putChannelMixingMatrix](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/ChannelMixingAudioProcessor#putChannelMixingMatrix(androidx.media3.common.audio.ChannelMixingMatrix))specifying mixing matrices to apply for each possible input channel count before using the audio processor. Input and output are 16-bit PCM.
## Summary
| ### Public constructors |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| [ChannelMixingAudioProcessor](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/ChannelMixingAudioProcessor#ChannelMixingAudioProcessor())`()` Creates a new audio processor for mixing and scaling audio channels. |
| ### Public functions |
|-------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| [Unit](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html) | [putChannelMixingMatrix](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/ChannelMixingAudioProcessor#putChannelMixingMatrix(androidx.media3.common.audio.ChannelMixingMatrix))`(matrix: `[ChannelMixingMatrix](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/ChannelMixingMatrix)`!)` Stores a channel mixing matrix for processing audio with a given[channel count](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/ChannelMixingMatrix#getInputChannelCount()). |
| [Unit](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html) | [queueInput](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/ChannelMixingAudioProcessor#queueInput(java.nio.ByteBuffer))`(inputBuffer: `[ByteBuffer](https://developer.android.com/reference/java/nio/ByteBuffer.html)`!)` Queues audio data between the position and limit of the`inputBuffer`for processing. |
| ### Protected functions |
|-----------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| [AudioProcessor.AudioFormat](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor.AudioFormat)`!` | [onConfigure](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/ChannelMixingAudioProcessor#onConfigure(androidx.media3.common.audio.AudioProcessor.AudioFormat))`(inputAudioFormat: `[AudioProcessor.AudioFormat](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor.AudioFormat)`!)` Called when the processor is configured for a new input format. |
| ### Inherited Constants |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| From[androidx.media3.common.audio.AudioProcessor](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor) |-------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `const `[ByteBuffer](https://developer.android.com/reference/java/nio/ByteBuffer.html)`!` | [EMPTY_BUFFER](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor#EMPTY_BUFFER()) An empty, direct[ByteBuffer](https://developer.android.com/reference/java/nio/ByteBuffer.html). | |
| ### Inherited functions |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------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| From[androidx.media3.common.audio.AudioProcessor](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor) |-------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | [Long](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-long/index.html) | [getDurationAfterProcessorApplied](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor#getDurationAfterProcessorApplied(long))`(durationUs: `[Long](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-long/index.html)`)` Returns the expected duration of the output stream when the processor is applied given a input`durationUs`. | |
| From[androidx.media3.common.audio.BaseAudioProcessor](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor) |-----------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | [AudioProcessor.AudioFormat](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor.AudioFormat)`!` | [configure](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#configure(androidx.media3.common.audio.AudioProcessor.AudioFormat))`(inputAudioFormat: `[AudioProcessor.AudioFormat](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor.AudioFormat)`!)` Configures the processor to process input audio with the specified format. | | [Unit](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html) | ~~[flush](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#flush())~~`()` **This function is deprecated.** Use[flush](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor#flush(androidx.media3.common.audio.AudioProcessor.StreamMetadata))instead.
| | [Unit](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html) | [flush](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#flush(androidx.media3.common.audio.AudioProcessor.StreamMetadata))`(streamMetadata: `[AudioProcessor.StreamMetadata](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor.StreamMetadata)`!)` Prepares the audio processor to receive a new stream of input in the last[configured format](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor#configure(androidx.media3.common.audio.AudioProcessor.AudioFormat))and clears any buffered data and pending output. | | [ByteBuffer](https://developer.android.com/reference/java/nio/ByteBuffer.html)`!` | `@`[CallSuper](https://developer.android.com/reference/kotlin/androidx/annotation/CallSuper) [getOutput](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#getOutput())`()` Returns a buffer containing processed output data between its position and limit. | | [Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html) | [hasPendingOutput](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#hasPendingOutput())`()` Returns whether the current output buffer has any data remaining. | | [Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html) | `@`[CallSuper](https://developer.android.com/reference/kotlin/androidx/annotation/CallSuper) [isActive](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#isActive())`()` Returns whether the processor is configured and will process input buffers. | | [Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html) | `@`[CallSuper](https://developer.android.com/reference/kotlin/androidx/annotation/CallSuper) [isEnded](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#isEnded())`()` Returns whether this processor will return no more output from[getOutput](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor#getOutput())until[flush](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor#flush())has been called and more input has been queued. | | [Unit](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html) | ~~[onFlush](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#onFlush())~~`()` **This function is deprecated.** Use[onFlush](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#onFlush(androidx.media3.common.audio.AudioProcessor.StreamMetadata))instead.
| | [Unit](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html) | [onFlush](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#onFlush(androidx.media3.common.audio.AudioProcessor.StreamMetadata))`(streamMetadata: `[AudioProcessor.StreamMetadata](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor.StreamMetadata)`!)` Called when the processor is[flushed](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor#flush(androidx.media3.common.audio.AudioProcessor.StreamMetadata)). | | [Unit](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html) | [onQueueEndOfStream](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#onQueueEndOfStream())`()` Called when the end-of-stream is queued to the processor. | | [Unit](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html) | [onReset](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#onReset())`()` Called when the processor is reset. | | [Unit](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html) | [queueEndOfStream](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#queueEndOfStream())`()` Queues an end of stream signal. | | [ByteBuffer](https://developer.android.com/reference/java/nio/ByteBuffer.html)`!` | [replaceOutputBuffer](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#replaceOutputBuffer(int))`(size: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html)`)` Replaces the current output buffer with a buffer of at least`size`bytes and returns it. | | [Unit](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html) | [reset](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#reset())`()` Resets the processor to its unconfigured state, releasing any resources. | |
| ### Inherited properties |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| From[androidx.media3.common.audio.BaseAudioProcessor](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor) |-----------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | [AudioProcessor.AudioFormat](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor.AudioFormat)`!` | [inputAudioFormat](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#inputAudioFormat()) The current input audio format. | | [AudioProcessor.AudioFormat](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor.AudioFormat)`!` | [outputAudioFormat](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/BaseAudioProcessor#outputAudioFormat()) The current output audio format. | |
## Public constructors
### ChannelMixingAudioProcessor
```
ChannelMixingAudioProcessor()
```
Creates a new audio processor for mixing and scaling audio channels.
## Public functions
### putChannelMixingMatrix
```
fun putChannelMixingMatrix(matrix: ChannelMixingMatrix!): Unit
```
Stores a channel mixing matrix for processing audio with a given[channel count](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/ChannelMixingMatrix#getInputChannelCount()). Overwrites any previously stored matrix for the same input channel count.
### queueInput
```
fun queueInput(inputBuffer: ByteBuffer!): Unit
```
Queues audio data between the position and limit of the`inputBuffer`for processing. After calling this method, processed output may be available via[getOutput](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor#getOutput()). Calling`queueInput(ByteBuffer)`again invalidates any pending output.
| Parameters |
|--------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `inputBuffer: `[ByteBuffer](https://developer.android.com/reference/java/nio/ByteBuffer.html)`!` | The input buffer to process. It 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. |
## Protected functions
### onConfigure
```
protected fun onConfigure(inputAudioFormat: AudioProcessor.AudioFormat!): AudioProcessor.AudioFormat!
```
Called when the processor is configured for a new input format.
| Throws |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---|
| [androidx.media3.common.audio.AudioProcessor.UnhandledAudioFormatException](https://developer.android.com/reference/kotlin/androidx/media3/common/audio/AudioProcessor.UnhandledAudioFormatException) | |