Scale AudioTrack buffer size for AudioTrack speed adjustment

PiperOrigin-RevId: 326642908

Scale AudioTrack buffer size for AudioTrack speed adjustment
PiperOrigin-RevId: 326642908
977f0d1e · andrewlewis · kim-vde · eabc486b · 977f0d1e · 977f0d1e
Commit 977f0d1e authored Aug 14, 2020 by andrewlewis Committed by kim-vde Aug 17, 2020
Showing with 31 additions and 30 deletions
library/core/src/main/java/com/google/android/exoplayer2/audio/DefaultAudioSink.java
library/core/src/main/java/com/google/android/exoplayer2/audio/SonicAudioProcessor.java
--- a/library/core/src/main/java/com/google/android/exoplayer2/audio/DefaultAudioSink.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/audio/DefaultAudioSink.java
@@ -191,6 +191,16 @@ public final class DefaultAudioSink implements AudioSink {
    }
  }
+  /** The default playback speed. */
+  public static final float DEFAULT_PLAYBACK_SPEED = 1f;
+  /** The minimum allowed playback speed. Lower values will be constrained to fall in range. */
+  public static final float MIN_PLAYBACK_SPEED = 0.1f;
+  /** The maximum allowed playback speed. Higher values will be constrained to fall in range. */
+  public static final float MAX_PLAYBACK_SPEED = 8f;
+  /** The default skip silence flag. */
+  private static final boolean DEFAULT_SKIP_SILENCE = false;
  @Documented
  @Retention(RetentionPolicy.SOURCE)
  @IntDef({OUTPUT_MODE_PCM, OUTPUT_MODE_OFFLOAD, OUTPUT_MODE_PASSTHROUGH})
@@ -210,11 +220,10 @@ public final class DefaultAudioSink implements AudioSink {
  private static final long OFFLOAD_BUFFER_DURATION_US = 50_000_000;
  /**
-   * A multiplication factor to apply to the minimum buffer size requested by the underlying
+   * A multiplication factor to apply to the minimum buffer size requested by the underlying {@link
-   * {@link AudioTrack}.
+   * AudioTrack}.
   */
  private static final int BUFFER_MULTIPLICATION_FACTOR = 4;
  /** To avoid underruns on some devices (e.g., Broadcom 7271), scale up the AC3 buffer duration. */
  private static final int AC3_BUFFER_MULTIPLICATION_FACTOR = 2;
@@ -239,10 +248,6 @@ public final class DefaultAudioSink implements AudioSink {
   */
  @SuppressLint("InlinedApi")
  private static final int WRITE_NON_BLOCKING = AudioTrack.WRITE_NON_BLOCKING;
-  /** The default playback speed. */
-  private static final float DEFAULT_PLAYBACK_SPEED = 1f;
-  /** The default skip silence flag. */
-  private static final boolean DEFAULT_SKIP_SILENCE = false;
  private static final String TAG = "AudioTrack";
@@ -582,6 +587,7 @@ public final class DefaultAudioSink implements AudioSink {
            outputChannelConfig,
            outputEncoding,
            specifiedBufferSize,
+            enableAudioTrackPlaybackParams,
            canApplyPlaybackParameters,
            availableAudioProcessors);
    if (isAudioTrackInitialized()) {
@@ -1007,6 +1013,7 @@ public final class DefaultAudioSink implements AudioSink {
  @Override
  public void setPlaybackSpeed(float playbackSpeed) {
+    playbackSpeed = Util.constrainValue(playbackSpeed, MIN_PLAYBACK_SPEED, MAX_PLAYBACK_SPEED);
    if (enableAudioTrackPlaybackParams && Util.SDK_INT >= 23) {
      setAudioTrackPlaybackSpeedV23(playbackSpeed);
    } else {
@@ -1802,6 +1809,7 @@ public final class DefaultAudioSink implements AudioSink {
        int outputChannelConfig,
        int outputEncoding,
        int specifiedBufferSize,
+        boolean enableAudioTrackPlaybackParams,
        boolean canApplyPlaybackParameters,
        AudioProcessor[] availableAudioProcessors) {
      this.inputFormat = inputFormat;
@@ -1815,7 +1823,7 @@ public final class DefaultAudioSink implements AudioSink {
      this.availableAudioProcessors = availableAudioProcessors;
      // Call computeBufferSize() last as it depends on the other configuration values.
-      this.bufferSize = computeBufferSize(specifiedBufferSize);
+      this.bufferSize = computeBufferSize(specifiedBufferSize, enableAudioTrackPlaybackParams);
    }
    /** Returns if the configurations are sufficiently compatible to reuse the audio track. */
@@ -1925,13 +1933,15 @@ public final class DefaultAudioSink implements AudioSink {
      }
    }
-    private int computeBufferSize(int specifiedBufferSize) {
+    private int computeBufferSize(
+        int specifiedBufferSize, boolean enableAudioTrackPlaybackParameters) {
      if (specifiedBufferSize != 0) {
        return specifiedBufferSize;
      }
      switch (outputMode) {
        case OUTPUT_MODE_PCM:
-          return getPcmDefaultBufferSize();
+          return getPcmDefaultBufferSize(
+              enableAudioTrackPlaybackParameters ? MAX_PLAYBACK_SPEED : DEFAULT_PLAYBACK_SPEED);
        case OUTPUT_MODE_OFFLOAD:
          return getEncodedDefaultBufferSize(OFFLOAD_BUFFER_DURATION_US);
        case OUTPUT_MODE_PASSTHROUGH:
@@ -1949,7 +1959,7 @@ public final class DefaultAudioSink implements AudioSink {
      return (int) (bufferDurationUs * rate / C.MICROS_PER_SECOND);
    }
-    private int getPcmDefaultBufferSize() {
+    private int getPcmDefaultBufferSize(float maxAudioTrackPlaybackSpeed) {
      int minBufferSize =
          AudioTrack.getMinBufferSize(outputSampleRate, outputChannelConfig, outputEncoding);
      Assertions.checkState(minBufferSize != ERROR_BAD_VALUE);
@@ -1957,7 +1967,13 @@ public final class DefaultAudioSink implements AudioSink {
      int minAppBufferSize = (int) durationUsToFrames(MIN_BUFFER_DURATION_US) * outputPcmFrameSize;
      int maxAppBufferSize =
          max(minBufferSize, (int) durationUsToFrames(MAX_BUFFER_DURATION_US) * outputPcmFrameSize);
-      return Util.constrainValue(multipliedBufferSize, minAppBufferSize, maxAppBufferSize);
+      int bufferSize =
+          Util.constrainValue(multipliedBufferSize, minAppBufferSize, maxAppBufferSize);
+      if (maxAudioTrackPlaybackSpeed != 1f) {
+        // Maintain the buffer duration by scaling the size accordingly.
+        bufferSize = Math.round(bufferSize * maxAudioTrackPlaybackSpeed);
+      }
+      return bufferSize;
    }
    @RequiresApi(21)

--- a/library/core/src/main/java/com/google/android/exoplayer2/audio/SonicAudioProcessor.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/audio/SonicAudioProcessor.java
@@ -29,22 +29,10 @@ import java.nio.ShortBuffer;
 */
 public final class SonicAudioProcessor implements AudioProcessor {
-  /**
+  /** Indicates that the output sample rate should be the same as the input. */
-   * The maximum allowed playback speed in {@link #setSpeed(float)}.
-   */
-  public static final float MAXIMUM_SPEED = 8.0f;
-  /**
-   * The minimum allowed playback speed in {@link #setSpeed(float)}.
-   */
-  public static final float MINIMUM_SPEED = 0.1f;
-  /**
-   * Indicates that the output sample rate should be the same as the input.
-   */
  public static final int SAMPLE_RATE_NO_CHANGE = -1;
-  /**
+  /** The threshold below which the difference between two pitch/speed factors is negligible. */
-   * The threshold below which the difference between two pitch/speed factors is negligible.
-   */
  private static final float CLOSE_THRESHOLD = 0.01f;
  /**
@@ -70,9 +58,7 @@ public final class SonicAudioProcessor implements AudioProcessor {
  private long outputBytes;
  private boolean inputEnded;
-  /**
+  /** Creates a new Sonic audio processor. */
-   * Creates a new Sonic audio processor.
-   */
  public SonicAudioProcessor() {
    speed = 1f;
    pendingInputAudioFormat = AudioFormat.NOT_SET;
@@ -94,7 +80,6 @@ public final class SonicAudioProcessor implements AudioProcessor {
   * @return The actual new playback speed.
   */
  public float setSpeed(float speed) {
-    speed = Util.constrainValue(speed, MINIMUM_SPEED, MAXIMUM_SPEED);
    if (this.speed != speed) {
      this.speed = speed;
      pendingSonicRecreation = true;