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Add AudioProcessor.AudioFormat
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Issue: #6601
PiperOrigin-RevId: 282515179
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@andrewlewis @ojw28
andrewlewis authored and ojw28 committed Nov 27, 2019
1 parent a2b3ad8 commit 07b3cbc
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Showing 13 changed files with 259 additions and 329 deletions.
46 changes: 15 additions & 31 deletions extensions/gvr/src/main/java/com/google/android/exoplayer2/ext/gvr/GvrAudioProcessor.java
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,6 @@
import androidx.annotation.Nullable;
import com.google.android.exoplayer2.C;
import com.google.android.exoplayer2.ExoPlayerLibraryInfo;
import com.google.android.exoplayer2.Format;
import com.google.android.exoplayer2.audio.AudioProcessor;
import com.google.android.exoplayer2.util.Assertions;
import com.google.vr.sdk.audio.GvrAudioSurround;
Expand All @@ -44,8 +43,7 @@ public final class GvrAudioProcessor implements AudioProcessor {
private static final int OUTPUT_FRAME_SIZE = OUTPUT_CHANNEL_COUNT * 2; // 16-bit stereo output.
private static final int NO_SURROUND_FORMAT = GvrAudioSurround.SurroundFormat.INVALID;

private int sampleRateHz;
private int channelCount;
private AudioFormat inputAudioFormat;
private int pendingGvrAudioSurroundFormat;
@Nullable private GvrAudioSurround gvrAudioSurround;
private ByteBuffer buffer;
Expand All @@ -60,8 +58,7 @@ public final class GvrAudioProcessor implements AudioProcessor {
public GvrAudioProcessor() {
// Use the identity for the initial orientation.
w = 1f;
sampleRateHz = Format.NO_VALUE;
channelCount = Format.NO_VALUE;
inputAudioFormat = AudioFormat.NOT_SET;
buffer = EMPTY_BUFFER;
pendingGvrAudioSurroundFormat = NO_SURROUND_FORMAT;
}
Expand All @@ -87,15 +84,13 @@ public synchronized void updateOrientation(float w, float x, float y, float z) {

@SuppressWarnings("ReferenceEquality")
@Override
public synchronized void configure(int sampleRateHz, int channelCount, @C.Encoding int encoding)
throws UnhandledFormatException {
if (encoding != C.ENCODING_PCM_16BIT) {
public synchronized AudioFormat configure(AudioFormat inputAudioFormat)
throws UnhandledAudioFormatException {
if (inputAudioFormat.encoding != C.ENCODING_PCM_16BIT) {
maybeReleaseGvrAudioSurround();
throw new UnhandledFormatException(sampleRateHz, channelCount, encoding);
throw new UnhandledAudioFormatException(inputAudioFormat);
}
this.sampleRateHz = sampleRateHz;
this.channelCount = channelCount;
switch (channelCount) {
switch (inputAudioFormat.channelCount) {
case 1:
pendingGvrAudioSurroundFormat = GvrAudioSurround.SurroundFormat.SURROUND_MONO;
break;
Expand All @@ -115,34 +110,21 @@ public synchronized void configure(int sampleRateHz, int channelCount, @C.Encodi
pendingGvrAudioSurroundFormat = GvrAudioSurround.SurroundFormat.THIRD_ORDER_AMBISONICS;
break;
default:
throw new UnhandledFormatException(sampleRateHz, channelCount, encoding);
throw new UnhandledAudioFormatException(inputAudioFormat);
}
if (buffer == EMPTY_BUFFER) {
buffer = ByteBuffer.allocateDirect(FRAMES_PER_OUTPUT_BUFFER * OUTPUT_FRAME_SIZE)
.order(ByteOrder.nativeOrder());
}
this.inputAudioFormat = inputAudioFormat;
return new AudioFormat(inputAudioFormat.sampleRate, OUTPUT_CHANNEL_COUNT, C.ENCODING_PCM_16BIT);
}

@Override
public boolean isActive() {
return pendingGvrAudioSurroundFormat != NO_SURROUND_FORMAT || gvrAudioSurround != null;
}

@Override
public int getOutputChannelCount() {
return OUTPUT_CHANNEL_COUNT;
}

@Override
public int getOutputEncoding() {
return C.ENCODING_PCM_16BIT;
}

@Override
public int getOutputSampleRateHz() {
return sampleRateHz;
}

@Override
public void queueInput(ByteBuffer input) {
int position = input.position();
Expand Down Expand Up @@ -181,7 +163,10 @@ public void flush() {
maybeReleaseGvrAudioSurround();
gvrAudioSurround =
new GvrAudioSurround(
pendingGvrAudioSurroundFormat, sampleRateHz, channelCount, FRAMES_PER_OUTPUT_BUFFER);
pendingGvrAudioSurroundFormat,
inputAudioFormat.sampleRate,
inputAudioFormat.channelCount,
FRAMES_PER_OUTPUT_BUFFER);
gvrAudioSurround.updateNativeOrientation(w, x, y, z);
pendingGvrAudioSurroundFormat = NO_SURROUND_FORMAT;
} else if (gvrAudioSurround != null) {
Expand All @@ -195,8 +180,7 @@ public synchronized void reset() {
maybeReleaseGvrAudioSurround();
updateOrientation(/* w= */ 1f, /* x= */ 0f, /* y= */ 0f, /* z= */ 0f);
inputEnded = false;
sampleRateHz = Format.NO_VALUE;
channelCount = Format.NO_VALUE;
inputAudioFormat = AudioFormat.NOT_SET;
buffer = EMPTY_BUFFER;
pendingGvrAudioSurroundFormat = NO_SURROUND_FORMAT;
}
Expand Down
94 changes: 53 additions & 41 deletions library/core/src/main/java/com/google/android/exoplayer2/audio/AudioProcessor.java
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Original file line number Diff line number Diff line change
Expand Up @@ -16,31 +16,65 @@
package com.google.android.exoplayer2.audio;

import com.google.android.exoplayer2.C;
import com.google.android.exoplayer2.Format;
import com.google.android.exoplayer2.util.Util;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

/**
* Interface for audio processors, which take audio data as input and transform it, potentially
* modifying its channel count, encoding and/or sample rate.
*
* <p>Call {@link #configure(int, int, int)} to configure the processor to receive input audio, then
* call {@link #isActive()} to determine whether the processor is active in the new configuration.
* {@link #queueInput(ByteBuffer)}, {@link #getOutputChannelCount()}, {@link #getOutputEncoding()}
* and {@link #getOutputSampleRateHz()} may only be called if the processor is active. Call {@link
* #reset()} to reset the processor to its unconfigured state and release any resources.
*
* <p>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.
*/
public interface AudioProcessor {

/** PCM audio format that may be handled by an audio processor. */
final class AudioFormat {
public static final AudioFormat NOT_SET =
new AudioFormat(
/* sampleRate= */ Format.NO_VALUE,
/* channelCount= */ Format.NO_VALUE,
/* encoding= */ Format.NO_VALUE);

/** The sample rate in Hertz. */
public final int sampleRate;
/** The number of interleaved channels. */
public final int channelCount;
/** The type of linear PCM encoding. */
@C.PcmEncoding public final int encoding;
/** The number of bytes used to represent one audio frame. */
public final int bytesPerFrame;

public AudioFormat(int sampleRate, int channelCount, @C.PcmEncoding int encoding) {
this.sampleRate = sampleRate;
this.channelCount = channelCount;
this.encoding = encoding;
bytesPerFrame =
Util.isEncodingLinearPcm(encoding)
? Util.getPcmFrameSize(encoding, channelCount)
: Format.NO_VALUE;
}

@Override
public String toString() {
return "AudioFormat["
+ "sampleRate="
+ sampleRate
+ ", channelCount="
+ channelCount
+ ", encoding="
+ encoding
+ ']';
}
}

/** Exception thrown when a processor can't be configured for a given input audio format. */
final class UnhandledFormatException extends Exception {
final class UnhandledAudioFormatException extends Exception {

public UnhandledFormatException(
int sampleRateHz, int channelCount, @C.PcmEncoding int encoding) {
super("Unhandled format: " + sampleRateHz + " Hz, " + channelCount + " channels in encoding "
+ encoding);
public UnhandledAudioFormatException(AudioFormat inputAudioFormat) {
super("Unhandled format: " + inputAudioFormat);
}

}
Expand All @@ -50,45 +84,23 @@ public UnhandledFormatException(

/**
* Configures the processor to process input audio with the specified format. After calling this
* method, call {@link #isActive()} to determine whether the audio processor is active.
*
* <p>If the audio processor is active after configuration, call {@link #getOutputSampleRateHz()},
* {@link #getOutputChannelCount()} and {@link #getOutputEncoding()} to get its new output format.
* method, call {@link #isActive()} to determine whether the audio processor is active. Returns
* the configured output audio format if this instance is active.
*
* <p>After calling this method, it is necessary to {@link #flush()} the processor to apply the
* new configuration before queueing more data. You can (optionally) first drain output in the
* previous configuration by calling {@link #queueEndOfStream()} and {@link #getOutput()}.
*
* @param sampleRateHz The sample rate of input audio in Hz.
* @param channelCount The number of interleaved channels in input audio.
* @param encoding The encoding of input audio.
* @throws UnhandledFormatException Thrown if the specified format can't be handled as input.
* @param inputAudioFormat The format of audio that will be queued after the next call to {@link
* #flush()}.
* @return The configured output audio format if this instance is {@link #isActive() active}.
* @throws UnhandledAudioFormatException Thrown if the specified format can't be handled as input.
*/
void configure(int sampleRateHz, int channelCount, @C.PcmEncoding int encoding)
throws UnhandledFormatException;
AudioFormat configure(AudioFormat inputAudioFormat) throws UnhandledAudioFormatException;

/** Returns whether the processor is configured and will process input buffers. */
boolean isActive();

/**
* Returns the number of audio channels in the data output by the processor. The value may change
* as a result of calling {@link #configure(int, int, int)}.
*/
int getOutputChannelCount();

/**
* Returns the audio encoding used in the data output by the processor. The value may change as a
* result of calling {@link #configure(int, int, int)}.
*/
@C.PcmEncoding
int getOutputEncoding();

/**
* Returns the sample rate of audio output by the processor, in hertz. The value may change as a
* result of calling {@link #configure(int, int, int)}.
*/
int getOutputSampleRateHz();

/**
* Queues audio data between the position and limit of the input {@code buffer} for processing.
* {@code buffer} must be a direct byte buffer with native byte order. Its contents are treated as
Expand Down Expand Up @@ -130,6 +142,6 @@ void configure(int sampleRateHz, int channelCount, @C.PcmEncoding int encoding)
*/
void flush();

/** Resets the processor to its unconfigured state. */
/** Resets the processor to its unconfigured state, releasing any resources. */
void reset();
}
59 changes: 22 additions & 37 deletions library/core/src/main/java/com/google/android/exoplayer2/audio/BaseAudioProcessor.java
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Original file line number Diff line number Diff line change
Expand Up @@ -16,54 +16,42 @@
package com.google.android.exoplayer2.audio;

import androidx.annotation.CallSuper;
import com.google.android.exoplayer2.C;
import com.google.android.exoplayer2.Format;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

/**
* Base class for audio processors that keep an output buffer and an internal buffer that is reused
* whenever input is queued.
* whenever input is queued. Subclasses should override {@link #onConfigure(AudioFormat)} to return
* the output audio format for the processor if it's active.
*/
public abstract class BaseAudioProcessor implements AudioProcessor {

/** The configured input sample rate, in Hertz, or {@link Format#NO_VALUE} if not configured. */
protected int sampleRateHz;
/** The configured input channel count, or {@link Format#NO_VALUE} if not configured. */
protected int channelCount;
/** The configured input encoding, or {@link Format#NO_VALUE} if not configured. */
@C.PcmEncoding protected int encoding;
/** The configured input audio format. */
protected AudioFormat inputAudioFormat;

private AudioFormat outputAudioFormat;
private ByteBuffer buffer;
private ByteBuffer outputBuffer;
private boolean inputEnded;

public BaseAudioProcessor() {
buffer = EMPTY_BUFFER;
outputBuffer = EMPTY_BUFFER;
channelCount = Format.NO_VALUE;
sampleRateHz = Format.NO_VALUE;
encoding = Format.NO_VALUE;
inputAudioFormat = AudioFormat.NOT_SET;
outputAudioFormat = AudioFormat.NOT_SET;
}

@Override
public boolean isActive() {
return sampleRateHz != Format.NO_VALUE;
}

@Override
public int getOutputChannelCount() {
return channelCount;
}

@Override
public int getOutputEncoding() {
return encoding;
public final AudioFormat configure(AudioFormat inputAudioFormat)
throws UnhandledAudioFormatException {
this.inputAudioFormat = inputAudioFormat;
outputAudioFormat = onConfigure(inputAudioFormat);
return isActive() ? outputAudioFormat : AudioFormat.NOT_SET;
}

@Override
public int getOutputSampleRateHz() {
return sampleRateHz;
public boolean isActive() {
return outputAudioFormat != AudioFormat.NOT_SET;
}

@Override
Expand Down Expand Up @@ -98,20 +86,11 @@ public final void flush() {
public final void reset() {
flush();
buffer = EMPTY_BUFFER;
sampleRateHz = Format.NO_VALUE;
channelCount = Format.NO_VALUE;
encoding = Format.NO_VALUE;
inputAudioFormat = AudioFormat.NOT_SET;
outputAudioFormat = AudioFormat.NOT_SET;
onReset();
}

/** Sets the input format of this processor. */
protected final void setInputFormat(
int sampleRateHz, int channelCount, @C.PcmEncoding int encoding) {
this.sampleRateHz = sampleRateHz;
this.channelCount = channelCount;
this.encoding = encoding;
}

/**
* Replaces the current output buffer with a buffer of at least {@code count} bytes and returns
* it. Callers should write to the returned buffer then {@link ByteBuffer#flip()} it so it can be
Expand All @@ -132,6 +111,12 @@ protected final boolean hasPendingOutput() {
return outputBuffer.hasRemaining();
}

/** Called when the processor is configured for a new input format. */
protected AudioFormat onConfigure(AudioFormat inputAudioFormat)
throws UnhandledAudioFormatException {
return AudioFormat.NOT_SET;
}

/** Called when the end-of-stream is queued to the processor. */
protected void onQueueEndOfStream() {
// Do nothing.
Expand Down
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