Adjust MediaCodec operating rate according to playback rate.

library/core/src/main/java/com/google/android/exoplayer2/BaseRenderer.java

@@ -136,6 +136,11 @@ public abstract class BaseRenderer implements Renderer, RendererCapabilities {
     onPositionReset(positionUs, false);
   }
 
+  @Override
+  public void setOperatingRate(float operatingRate) {
+    onOperatingRateChanged(operatingRate);
+  }
+
   @Override
   public final void stop() throws ExoPlaybackException {
     Assertions.checkState(state == STATE_STARTED);
@@ -216,6 +221,17 @@ public abstract class BaseRenderer implements Renderer, RendererCapabilities {
     // Do nothing.
   }
 
+  /**
+   * Called when the operating rate is changed.
+   * <p>
+   * The default implementation is a no-op.
+   *
+   * @param operatingRate The new operating rate.
+   */
+  protected void onOperatingRateChanged(float operatingRate) {
+    // Do nothing.
+  }
+
   /**
    * Called when the renderer is started.
    * <p>

library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImplInternal.java

@@ -273,6 +273,7 @@ import java.util.Collections;
   public void onPlaybackParametersChanged(PlaybackParameters playbackParameters) {
     eventHandler.obtainMessage(MSG_PLAYBACK_PARAMETERS_CHANGED, playbackParameters).sendToTarget();
     updateTrackSelectionPlaybackSpeed(playbackParameters.speed);
+    updateRendererOperatingRate(playbackParameters.speed);
   }
 
   // Handler.Callback implementation.
@@ -1075,6 +1076,14 @@ import java.util.Collections;
     }
   }
 
+  private void updateRendererOperatingRate(float operatingRate) {
+    for (Renderer renderer : renderers) {
+      if (renderer != null) {
+        renderer.setOperatingRate(operatingRate);
+      }
+    }
+  }
+
   private boolean shouldTransitionToReadyState(boolean renderersReadyOrEnded) {
     if (enabledRenderers.length == 0) {
       // If there are no enabled renderers, determine whether we're ready based on the timeline.

library/core/src/main/java/com/google/android/exoplayer2/Renderer.java

@@ -192,6 +192,13 @@ public interface Renderer extends PlayerMessage.Target {
    */
   void resetPosition(long positionUs) throws ExoPlaybackException;
 
+  /**
+   * Sets the operating rate of this renderer.
+   *
+   * @param operatingRate The renderer operating rate.
+   */
+  void setOperatingRate(float operatingRate);
+
   /**
    * Incrementally renders the {@link SampleStream}.
    * <p>

library/core/src/main/java/com/google/android/exoplayer2/audio/MediaCodecAudioRenderer.java

@@ -21,6 +21,7 @@ import android.media.MediaCodec;
 import android.media.MediaCrypto;
 import android.media.MediaFormat;
 import android.media.audiofx.Virtualizer;
+import android.os.Bundle;
 import android.os.Handler;
 import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
@@ -286,6 +287,19 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
     return this;
   }
 
+  @TargetApi(23)
+  @Override
+  protected void updateCodecOperatingRate(Format format) {
+    if (format.sampleRate == Format.NO_VALUE) {
+      return;
+    }
+    MediaCodec codec = getCodec();
+    float codecOperatingRate = getCodecOperatingRate();
+    Bundle codecParameters = new Bundle();
+    codecParameters.putFloat(MediaFormat.KEY_OPERATING_RATE, format.sampleRate * codecOperatingRate);
+    codec.setParameters(codecParameters);
+  }
+
   @Override
   protected void onCodecInitialized(String name, long initializedTimestampMs,
       long initializationDurationMs) {
@@ -550,6 +564,11 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
     // Set codec configuration values.
     if (Util.SDK_INT >= 23) {
       mediaFormat.setInteger(MediaFormat.KEY_PRIORITY, 0 /* realtime priority */);
+      if (format.sampleRate != Format.NO_VALUE) {
+        float codecOperatingRate = getCodecOperatingRate();
+        mediaFormat.setFloat(
+            MediaFormat.KEY_OPERATING_RATE, codecOperatingRate * format.sampleRate);
+      }
     }
     return mediaFormat;
   }

library/core/src/main/java/com/google/android/exoplayer2/mediacodec/MediaCodecRenderer.java

@@ -228,6 +228,7 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
   private DrmSession<FrameworkMediaCrypto> pendingDrmSession;
   private MediaCodec codec;
   private MediaCodecInfo codecInfo;
+  private float codecOperatingRate = 1;
   private @AdaptationWorkaroundMode int codecAdaptationWorkaroundMode;
   private boolean codecNeedsDiscardToSpsWorkaround;
   private boolean codecNeedsFlushWorkaround;
@@ -450,6 +451,8 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
     return codecInfo;
   }
 
+  protected final float getCodecOperatingRate() { return codecOperatingRate; }
+
   @Override
   protected void onEnabled(boolean joining) throws ExoPlaybackException {
     decoderCounters = new DecoderCounters();
@@ -464,6 +467,14 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
     }
   }
 
+  @Override
+  protected void onOperatingRateChanged(float operatingRate) {
+    codecOperatingRate = operatingRate;
+    if (codec != null && format != null) {
+      updateCodecOperatingRate(format);
+    }
+  }
+
   @Override
   protected void onDisabled() {
     format = null;
@@ -916,9 +927,22 @@ public abstract class MediaCodecRenderer extends BaseRenderer {
         releaseCodec();
         maybeInitCodec();
       }
+    } else {
+      if (Util.SDK_INT >= 23) {
+        updateCodecOperatingRate(format);
+      }
     }
   }
 
+  /**
+   * Updates the {@link MediaCodec} operating rate.
+   * <p>
+   * The default implementation is a no-op.
+   */
+  protected void updateCodecOperatingRate(Format format) {
+    // Do nothing.
+  }
+
   /**
    * Called when the output format of the {@link MediaCodec} changes.
    * <p>

library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java

@@ -23,6 +23,7 @@ import android.media.MediaCodec;
 import android.media.MediaCodecInfo.CodecCapabilities;
 import android.media.MediaCrypto;
 import android.media.MediaFormat;
+import android.os.Bundle;
 import android.os.Handler;
 import android.os.SystemClock;
 import android.support.annotation.CallSuper;
@@ -471,6 +472,19 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
     buffersInCodecCount = 0;
   }
 
+  @TargetApi(23)
+  @Override
+  protected void updateCodecOperatingRate(Format format) {
+    if (format.frameRate == Format.NO_VALUE) {
+      return;
+    }
+    MediaCodec codec = getCodec();
+    float codecOperatingRate = getCodecOperatingRate();
+    Bundle codecParameters = new Bundle();
+    codecParameters.putFloat(MediaFormat.KEY_OPERATING_RATE, format.frameRate * codecOperatingRate);
+    codec.setParameters(codecParameters);
+  }
+
   @Override
   protected void onCodecInitialized(String name, long initializedTimestampMs,
       long initializationDurationMs) {
@@ -969,6 +983,10 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
     // Set codec configuration values.
     if (Util.SDK_INT >= 23) {
       mediaFormat.setInteger(MediaFormat.KEY_PRIORITY, 0 /* realtime priority */);
+      if (format.frameRate != Format.NO_VALUE) {
+        float codecOperatingRate = getCodecOperatingRate();
+        mediaFormat.setFloat(MediaFormat.KEY_OPERATING_RATE, codecOperatingRate * format.frameRate);
+      }
     }
     if (deviceNeedsAutoFrcWorkaround) {
       mediaFormat.setInteger("auto-frc", 0);