public class

DefaultAudioTrackBufferSizeProvider

extends java.lang.Object

implements androidx.media3.exoplayer.audio.DefaultAudioSink.AudioTrackBufferSizeProvider

 java.lang.Object

↳androidx.media3.exoplayer.audio.DefaultAudioTrackBufferSizeProvider

Gradle dependencies

compile group: 'androidx.media3', name: 'media3-exoplayer', version: '1.0.0-alpha03'

  • groupId: androidx.media3
  • artifactId: media3-exoplayer
  • version: 1.0.0-alpha03

Artifact androidx.media3:media3-exoplayer:1.0.0-alpha03 it located at Google repository (https://maven.google.com/)

Overview

Provide the buffer size to use when creating an AudioTrack.

Summary

Fields
public final intac3BufferMultiplicationFactor

The multiplication factor to apply to AC3 passthrough buffer to avoid underruns on some devices (e.g., Broadcom 7271).

protected final intmaxPcmBufferDurationUs

The maximum length for PCM AudioTrack buffers, in microseconds.

protected final intminPcmBufferDurationUs

The minimum length for PCM AudioTrack buffers, in microseconds.

protected final intoffloadBufferDurationUs

The length for offload AudioTrack buffers, in microseconds.

protected final intpassthroughBufferDurationUs

The length for passthrough AudioTrack buffers, in microseconds.

protected final intpcmBufferMultiplicationFactor

The multiplication factor to apply to the minimum buffer size requested.

Constructors
protectedDefaultAudioTrackBufferSizeProvider(DefaultAudioTrackBufferSizeProvider.Builder builder)

Methods
protected static intdurationUsToBytes(int durationUs, int samplingRate, int frameSize)

protected intget1xBufferSizeInBytes(int minBufferSizeInBytes, int encoding, int outputMode, int pcmFrameSize, int sampleRate)

Returns the buffer size for playback at 1x speed.

public intgetBufferSizeInBytes(int minBufferSizeInBytes, int encoding, int outputMode, int pcmFrameSize, int sampleRate, double maxAudioTrackPlaybackSpeed)

protected static intgetMaximumEncodedRateBytesPerSecond(int encoding)

protected intgetOffloadBufferSizeInBytes(int encoding)

Returns the buffer size for offload playback.

protected intgetPassthroughBufferSizeInBytes(int encoding)

Returns the buffer size for passthrough playback.

protected intgetPcmBufferSizeInBytes(int minBufferSizeInBytes, int samplingRate, int frameSize)

Returns the buffer size for PCM playback.

from java.lang.Objectclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Fields

protected final int minPcmBufferDurationUs

The minimum length for PCM AudioTrack buffers, in microseconds.

protected final int maxPcmBufferDurationUs

The maximum length for PCM AudioTrack buffers, in microseconds.

protected final int pcmBufferMultiplicationFactor

The multiplication factor to apply to the minimum buffer size requested.

protected final int passthroughBufferDurationUs

The length for passthrough AudioTrack buffers, in microseconds.

protected final int offloadBufferDurationUs

The length for offload AudioTrack buffers, in microseconds.

public final int ac3BufferMultiplicationFactor

The multiplication factor to apply to AC3 passthrough buffer to avoid underruns on some devices (e.g., Broadcom 7271).

Constructors

protected DefaultAudioTrackBufferSizeProvider(DefaultAudioTrackBufferSizeProvider.Builder builder)

Methods

public int getBufferSizeInBytes(int minBufferSizeInBytes, int encoding, int outputMode, int pcmFrameSize, int sampleRate, double maxAudioTrackPlaybackSpeed)

protected int get1xBufferSizeInBytes(int minBufferSizeInBytes, int encoding, int outputMode, int pcmFrameSize, int sampleRate)

Returns the buffer size for playback at 1x speed.

protected int getPcmBufferSizeInBytes(int minBufferSizeInBytes, int samplingRate, int frameSize)

Returns the buffer size for PCM playback.

protected int getPassthroughBufferSizeInBytes(int encoding)

Returns the buffer size for passthrough playback.

protected int getOffloadBufferSizeInBytes(int encoding)

Returns the buffer size for offload playback.

protected static int durationUsToBytes(int durationUs, int samplingRate, int frameSize)

protected static int getMaximumEncodedRateBytesPerSecond(int encoding)

Source

/*
 * Copyright (C) 2021 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package androidx.media3.exoplayer.audio;

import static androidx.media3.common.util.Util.constrainValue;
import static androidx.media3.exoplayer.audio.DefaultAudioSink.OUTPUT_MODE_OFFLOAD;
import static androidx.media3.exoplayer.audio.DefaultAudioSink.OUTPUT_MODE_PASSTHROUGH;
import static androidx.media3.exoplayer.audio.DefaultAudioSink.OUTPUT_MODE_PCM;
import static com.google.common.primitives.Ints.checkedCast;
import static java.lang.Math.max;

import android.media.AudioTrack;
import androidx.media3.common.C;
import androidx.media3.common.Format;
import androidx.media3.common.util.UnstableApi;
import androidx.media3.exoplayer.audio.DefaultAudioSink.OutputMode;
import androidx.media3.extractor.AacUtil;
import androidx.media3.extractor.Ac3Util;
import androidx.media3.extractor.Ac4Util;
import androidx.media3.extractor.DtsUtil;
import androidx.media3.extractor.MpegAudioUtil;

/** Provide the buffer size to use when creating an {@link AudioTrack}. */
@UnstableApi
public class DefaultAudioTrackBufferSizeProvider
    implements DefaultAudioSink.AudioTrackBufferSizeProvider {

  /** Default minimum length for the {@link AudioTrack} buffer, in microseconds. */
  private static final int MIN_PCM_BUFFER_DURATION_US = 250_000;
  /** Default maximum length for the {@link AudioTrack} buffer, in microseconds. */
  private static final int MAX_PCM_BUFFER_DURATION_US = 750_000;
  /** Default multiplication factor to apply to the minimum buffer size requested. */
  private static final int PCM_BUFFER_MULTIPLICATION_FACTOR = 4;
  /** Default length for passthrough {@link AudioTrack} buffers, in microseconds. */
  private static final int PASSTHROUGH_BUFFER_DURATION_US = 250_000;
  /** Default length for offload {@link AudioTrack} buffers, in microseconds. */
  private static final int OFFLOAD_BUFFER_DURATION_US = 50_000_000;
  /**
   * Default multiplication factor to apply to AC3 passthrough buffer to avoid underruns on some
   * devices (e.g., Broadcom 7271).
   */
  private static final int AC3_BUFFER_MULTIPLICATION_FACTOR = 2;

  /** A builder to create {@link DefaultAudioTrackBufferSizeProvider} instances. */
  public static class Builder {

    private int minPcmBufferDurationUs;
    private int maxPcmBufferDurationUs;
    private int pcmBufferMultiplicationFactor;
    private int passthroughBufferDurationUs;
    private int offloadBufferDurationUs;
    private int ac3BufferMultiplicationFactor;

    /** Creates a new builder. */
    public Builder() {
      minPcmBufferDurationUs = MIN_PCM_BUFFER_DURATION_US;
      maxPcmBufferDurationUs = MAX_PCM_BUFFER_DURATION_US;
      pcmBufferMultiplicationFactor = PCM_BUFFER_MULTIPLICATION_FACTOR;
      passthroughBufferDurationUs = PASSTHROUGH_BUFFER_DURATION_US;
      offloadBufferDurationUs = OFFLOAD_BUFFER_DURATION_US;
      ac3BufferMultiplicationFactor = AC3_BUFFER_MULTIPLICATION_FACTOR;
    }

    /**
     * Sets the minimum length for PCM {@link AudioTrack} buffers, in microseconds. Default is
     * {@value #MIN_PCM_BUFFER_DURATION_US}.
     */
    public Builder setMinPcmBufferDurationUs(int minPcmBufferDurationUs) {
      this.minPcmBufferDurationUs = minPcmBufferDurationUs;
      return this;
    }

    /**
     * Sets the maximum length for PCM {@link AudioTrack} buffers, in microseconds. Default is
     * {@value #MAX_PCM_BUFFER_DURATION_US}.
     */
    public Builder setMaxPcmBufferDurationUs(int maxPcmBufferDurationUs) {
      this.maxPcmBufferDurationUs = maxPcmBufferDurationUs;
      return this;
    }

    /**
     * Sets the multiplication factor to apply to the minimum buffer size requested. Default is
     * {@value #PCM_BUFFER_MULTIPLICATION_FACTOR}.
     */
    public Builder setPcmBufferMultiplicationFactor(int pcmBufferMultiplicationFactor) {
      this.pcmBufferMultiplicationFactor = pcmBufferMultiplicationFactor;
      return this;
    }

    /**
     * Sets the length for passthrough {@link AudioTrack} buffers, in microseconds. Default is
     * {@value #PASSTHROUGH_BUFFER_DURATION_US}.
     */
    public Builder setPassthroughBufferDurationUs(int passthroughBufferDurationUs) {
      this.passthroughBufferDurationUs = passthroughBufferDurationUs;
      return this;
    }

    /**
     * The length for offload {@link AudioTrack} buffers, in microseconds. Default is {@value
     * #OFFLOAD_BUFFER_DURATION_US}.
     */
    public Builder setOffloadBufferDurationUs(int offloadBufferDurationUs) {
      this.offloadBufferDurationUs = offloadBufferDurationUs;
      return this;
    }

    /**
     * Sets the multiplication factor to apply to the passthrough buffer for AC3 to avoid underruns
     * on some devices (e.g., Broadcom 7271). Default is {@value #AC3_BUFFER_MULTIPLICATION_FACTOR}.
     */
    public Builder setAc3BufferMultiplicationFactor(int ac3BufferMultiplicationFactor) {
      this.ac3BufferMultiplicationFactor = ac3BufferMultiplicationFactor;
      return this;
    }

    /** Build the {@link DefaultAudioTrackBufferSizeProvider}. */
    public DefaultAudioTrackBufferSizeProvider build() {
      return new DefaultAudioTrackBufferSizeProvider(this);
    }
  }

  /** The minimum length for PCM {@link AudioTrack} buffers, in microseconds. */
  protected final int minPcmBufferDurationUs;
  /** The maximum length for PCM {@link AudioTrack} buffers, in microseconds. */
  protected final int maxPcmBufferDurationUs;
  /** The multiplication factor to apply to the minimum buffer size requested. */
  protected final int pcmBufferMultiplicationFactor;
  /** The length for passthrough {@link AudioTrack} buffers, in microseconds. */
  protected final int passthroughBufferDurationUs;
  /** The length for offload {@link AudioTrack} buffers, in microseconds. */
  protected final int offloadBufferDurationUs;
  /**
   * The multiplication factor to apply to AC3 passthrough buffer to avoid underruns on some devices
   * (e.g., Broadcom 7271).
   */
  public final int ac3BufferMultiplicationFactor;

  protected DefaultAudioTrackBufferSizeProvider(Builder builder) {
    minPcmBufferDurationUs = builder.minPcmBufferDurationUs;
    maxPcmBufferDurationUs = builder.maxPcmBufferDurationUs;
    pcmBufferMultiplicationFactor = builder.pcmBufferMultiplicationFactor;
    passthroughBufferDurationUs = builder.passthroughBufferDurationUs;
    offloadBufferDurationUs = builder.offloadBufferDurationUs;
    ac3BufferMultiplicationFactor = builder.ac3BufferMultiplicationFactor;
  }

  @Override
  public int getBufferSizeInBytes(
      int minBufferSizeInBytes,
      @C.Encoding int encoding,
      @OutputMode int outputMode,
      int pcmFrameSize,
      int sampleRate,
      double maxAudioTrackPlaybackSpeed) {
    int bufferSize =
        get1xBufferSizeInBytes(
            minBufferSizeInBytes, encoding, outputMode, pcmFrameSize, sampleRate);
    // Maintain the buffer duration by scaling the size accordingly.
    bufferSize = (int) (bufferSize * maxAudioTrackPlaybackSpeed);
    // Buffer size must not be lower than the AudioTrack min buffer size for this format.
    bufferSize = max(minBufferSizeInBytes, bufferSize);
    // Increase if needed to make sure the buffers contains an integer number of frames.
    return (bufferSize + pcmFrameSize - 1) / pcmFrameSize * pcmFrameSize;
  }

  /** Returns the buffer size for playback at 1x speed. */
  protected int get1xBufferSizeInBytes(
      int minBufferSizeInBytes, int encoding, int outputMode, int pcmFrameSize, int sampleRate) {
    switch (outputMode) {
      case OUTPUT_MODE_PCM:
        return getPcmBufferSizeInBytes(minBufferSizeInBytes, sampleRate, pcmFrameSize);
      case OUTPUT_MODE_PASSTHROUGH:
        return getPassthroughBufferSizeInBytes(encoding);
      case OUTPUT_MODE_OFFLOAD:
        return getOffloadBufferSizeInBytes(encoding);
      default:
        throw new IllegalArgumentException();
    }
  }

  /** Returns the buffer size for PCM playback. */
  protected int getPcmBufferSizeInBytes(int minBufferSizeInBytes, int samplingRate, int frameSize) {
    int targetBufferSize = minBufferSizeInBytes * pcmBufferMultiplicationFactor;
    int minAppBufferSize = durationUsToBytes(minPcmBufferDurationUs, samplingRate, frameSize);
    int maxAppBufferSize = durationUsToBytes(maxPcmBufferDurationUs, samplingRate, frameSize);
    return constrainValue(targetBufferSize, minAppBufferSize, maxAppBufferSize);
  }

  /** Returns the buffer size for passthrough playback. */
  protected int getPassthroughBufferSizeInBytes(@C.Encoding int encoding) {
    int bufferSizeUs = passthroughBufferDurationUs;
    if (encoding == C.ENCODING_AC3) {
      bufferSizeUs *= ac3BufferMultiplicationFactor;
    }
    int maxByteRate = getMaximumEncodedRateBytesPerSecond(encoding);
    return checkedCast((long) bufferSizeUs * maxByteRate / C.MICROS_PER_SECOND);
  }

  /** Returns the buffer size for offload playback. */
  protected int getOffloadBufferSizeInBytes(@C.Encoding int encoding) {
    int maxByteRate = getMaximumEncodedRateBytesPerSecond(encoding);
    return checkedCast((long) offloadBufferDurationUs * maxByteRate / C.MICROS_PER_SECOND);
  }

  protected static int durationUsToBytes(int durationUs, int samplingRate, int frameSize) {
    return checkedCast((long) durationUs * samplingRate * frameSize / C.MICROS_PER_SECOND);
  }

  protected static int getMaximumEncodedRateBytesPerSecond(@C.Encoding int encoding) {
    switch (encoding) {
      case C.ENCODING_MP3:
        return MpegAudioUtil.MAX_RATE_BYTES_PER_SECOND;
      case C.ENCODING_AAC_LC:
        return AacUtil.AAC_LC_MAX_RATE_BYTES_PER_SECOND;
      case C.ENCODING_AAC_HE_V1:
        return AacUtil.AAC_HE_V1_MAX_RATE_BYTES_PER_SECOND;
      case C.ENCODING_AAC_HE_V2:
        return AacUtil.AAC_HE_V2_MAX_RATE_BYTES_PER_SECOND;
      case C.ENCODING_AAC_XHE:
        return AacUtil.AAC_XHE_MAX_RATE_BYTES_PER_SECOND;
      case C.ENCODING_AAC_ELD:
        return AacUtil.AAC_ELD_MAX_RATE_BYTES_PER_SECOND;
      case C.ENCODING_AC3:
        return Ac3Util.AC3_MAX_RATE_BYTES_PER_SECOND;
      case C.ENCODING_E_AC3:
      case C.ENCODING_E_AC3_JOC:
        return Ac3Util.E_AC3_MAX_RATE_BYTES_PER_SECOND;
      case C.ENCODING_AC4:
        return Ac4Util.MAX_RATE_BYTES_PER_SECOND;
      case C.ENCODING_DTS:
        return DtsUtil.DTS_MAX_RATE_BYTES_PER_SECOND;
      case C.ENCODING_DTS_HD:
        return DtsUtil.DTS_HD_MAX_RATE_BYTES_PER_SECOND;
      case C.ENCODING_DOLBY_TRUEHD:
        return Ac3Util.TRUEHD_MAX_RATE_BYTES_PER_SECOND;
      case C.ENCODING_PCM_16BIT:
      case C.ENCODING_PCM_16BIT_BIG_ENDIAN:
      case C.ENCODING_PCM_24BIT:
      case C.ENCODING_PCM_32BIT:
      case C.ENCODING_PCM_8BIT:
      case C.ENCODING_PCM_FLOAT:
      case C.ENCODING_AAC_ER_BSAC:
      case C.ENCODING_INVALID:
      case Format.NO_VALUE:
      default:
        throw new IllegalArgumentException();
    }
  }
}