Factor out common audio processor functionality

PiperOrigin-RevId: 234025553

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

@@ -38,7 +38,8 @@ public interface AudioProcessor {
   /** Exception thrown when a processor can't be configured for a given input audio format. */
   final class UnhandledFormatException extends Exception {
 
-    public UnhandledFormatException(int sampleRateHz, int channelCount, @C.Encoding int encoding) {
+    public UnhandledFormatException(
+        int sampleRateHz, int channelCount, @C.PcmEncoding int encoding) {
       super("Unhandled format: " + sampleRateHz + " Hz, " + channelCount + " channels in encoding "
           + encoding);
     }
@@ -60,7 +61,7 @@ public interface AudioProcessor {
    * @return Whether to {@link #flush()} the processor.
    * @throws UnhandledFormatException Thrown if the specified format can't be handled as input.
    */
-  boolean configure(int sampleRateHz, int channelCount, @C.Encoding int encoding)
+  boolean configure(int sampleRateHz, int channelCount, @C.PcmEncoding int encoding)
       throws UnhandledFormatException;
 
   /** Returns whether the processor is configured and will process input buffers. */
@@ -78,7 +79,7 @@ public interface AudioProcessor {
    * result of calling {@link #configure(int, int, int)} and is undefined if the instance is not
    * active.
    */
-  @C.Encoding
+  @C.PcmEncoding
   int getOutputEncoding();
 
   /**

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

@@ -0,0 +1,155 @@
+/*
+ * Copyright (C) 2019 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 com.google.android.exoplayer2.audio;
+
+import android.support.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.
+ */
+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;
+
+  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;
+  }
+
+  @Override
+  public boolean isActive() {
+    return sampleRateHz != Format.NO_VALUE;
+  }
+
+  @Override
+  public int getOutputChannelCount() {
+    return channelCount;
+  }
+
+  @Override
+  public int getOutputEncoding() {
+    return encoding;
+  }
+
+  @Override
+  public int getOutputSampleRateHz() {
+    return sampleRateHz;
+  }
+
+  @Override
+  public final void queueEndOfStream() {
+    inputEnded = true;
+    onQueueEndOfStream();
+  }
+
+  @CallSuper
+  @Override
+  public ByteBuffer getOutput() {
+    ByteBuffer outputBuffer = this.outputBuffer;
+    this.outputBuffer = EMPTY_BUFFER;
+    return outputBuffer;
+  }
+
+  @CallSuper
+  @SuppressWarnings("ReferenceEquality")
+  @Override
+  public boolean isEnded() {
+    return inputEnded && outputBuffer == EMPTY_BUFFER;
+  }
+
+  @Override
+  public final void flush() {
+    outputBuffer = EMPTY_BUFFER;
+    inputEnded = false;
+    onFlush();
+  }
+
+  @Override
+  public final void reset() {
+    flush();
+    buffer = EMPTY_BUFFER;
+    sampleRateHz = Format.NO_VALUE;
+    channelCount = Format.NO_VALUE;
+    encoding = Format.NO_VALUE;
+    onReset();
+  }
+
+  /** Sets the input format of this processor, returning whether the input format has changed. */
+  protected final boolean setInputFormat(
+      int sampleRateHz, int channelCount, @C.PcmEncoding int encoding) {
+    if (sampleRateHz == this.sampleRateHz
+        && channelCount == this.channelCount
+        && encoding == this.encoding) {
+      return false;
+    }
+    this.sampleRateHz = sampleRateHz;
+    this.channelCount = channelCount;
+    this.encoding = encoding;
+    return true;
+  }
+
+  /**
+   * 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
+   * read via {@link #getOutput()}.
+   */
+  protected final ByteBuffer replaceOutputBuffer(int count) {
+    if (buffer.capacity() < count) {
+      buffer = ByteBuffer.allocateDirect(count).order(ByteOrder.nativeOrder());
+    } else {
+      buffer.clear();
+    }
+    outputBuffer = buffer;
+    return buffer;
+  }
+
+  /** Returns whether the current output buffer has any data remaining. */
+  protected final boolean hasPendingOutput() {
+    return outputBuffer.hasRemaining();
+  }
+
+  /** Called when the end-of-stream is queued to the processor. */
+  protected void onQueueEndOfStream() {
+    // Do nothing.
+  }
+
+  /** Called when the processor is flushed, directly or as part of resetting. */
+  protected void onFlush() {
+    // Do nothing.
+  }
+
+  /** Called when the processor is reset. */
+  protected void onReset() {
+    // Do nothing.
+  }
+}

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

@@ -17,36 +17,20 @@ package com.google.android.exoplayer2.audio;
 
 import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
-import com.google.android.exoplayer2.C.Encoding;
-import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.util.Assertions;
 import java.nio.ByteBuffer;
-import java.nio.ByteOrder;
 import java.util.Arrays;
 
 /**
  * An {@link AudioProcessor} that applies a mapping from input channels onto specified output
  * channels. This can be used to reorder, duplicate or discard channels.
  */
-/* package */ final class ChannelMappingAudioProcessor implements AudioProcessor {
+/* package */ final class ChannelMappingAudioProcessor extends BaseAudioProcessor {
 
-  private int channelCount;
-  private int sampleRateHz;
   @Nullable private int[] pendingOutputChannels;
 
   private boolean active;
   @Nullable private int[] outputChannels;
-  private ByteBuffer buffer;
-  private ByteBuffer outputBuffer;
-  private boolean inputEnded;
-
-  /** Creates a new processor that applies a channel mapping. */
-  public ChannelMappingAudioProcessor() {
-    buffer = EMPTY_BUFFER;
-    outputBuffer = EMPTY_BUFFER;
-    channelCount = Format.NO_VALUE;
-    sampleRateHz = Format.NO_VALUE;
-  }
 
   /**
    * Resets the channel mapping. After calling this method, call {@link #configure(int, int, int)}
@@ -61,10 +45,12 @@ import java.util.Arrays;
   }
 
   @Override
-  public boolean configure(int sampleRateHz, int channelCount, @Encoding int encoding)
+  public boolean configure(int sampleRateHz, int channelCount, @C.PcmEncoding int encoding)
       throws UnhandledFormatException {
     boolean outputChannelsChanged = !Arrays.equals(pendingOutputChannels, outputChannels);
     outputChannels = pendingOutputChannels;
+
+    int[] outputChannels = this.outputChannels;
     if (outputChannels == null) {
       active = false;
       return outputChannelsChanged;
@@ -72,12 +58,9 @@ import java.util.Arrays;
     if (encoding != C.ENCODING_PCM_16BIT) {
       throw new UnhandledFormatException(sampleRateHz, channelCount, encoding);
     }
-    if (!outputChannelsChanged && this.sampleRateHz == sampleRateHz
+    if (!outputChannelsChanged && !setInputFormat(sampleRateHz, channelCount, encoding)) {
-        && this.channelCount == channelCount) {
       return false;
     }
-    this.sampleRateHz = sampleRateHz;
-    this.channelCount = channelCount;
 
     active = channelCount != outputChannels.length;
     for (int i = 0; i < outputChannels.length; i++) {
@@ -100,16 +83,6 @@ import java.util.Arrays;
     return outputChannels == null ? channelCount : outputChannels.length;
   }
 
-  @Override
-  public int getOutputEncoding() {
-    return C.ENCODING_PCM_16BIT;
-  }
-
-  @Override
-  public int getOutputSampleRateHz() {
-    return sampleRateHz;
-  }
-
   @Override
   public void queueInput(ByteBuffer inputBuffer) {
     int[] outputChannels = Assertions.checkNotNull(this.outputChannels);
@@ -117,11 +90,7 @@ import java.util.Arrays;
     int limit = inputBuffer.limit();
     int frameCount = (limit - position) / (2 * channelCount);
     int outputSize = frameCount * outputChannels.length * 2;
-    if (buffer.capacity() < outputSize) {
+    ByteBuffer buffer = replaceOutputBuffer(outputSize);
-      buffer = ByteBuffer.allocateDirect(outputSize).order(ByteOrder.nativeOrder());
-    } else {
-      buffer.clear();
-    }
     while (position < limit) {
       for (int channelIndex : outputChannels) {
         buffer.putShort(inputBuffer.getShort(position + 2 * channelIndex));
@@ -130,39 +99,10 @@ import java.util.Arrays;
     }
     inputBuffer.position(limit);
     buffer.flip();
-    outputBuffer = buffer;
   }
 
   @Override
-  public void queueEndOfStream() {
+  protected void onReset() {
-    inputEnded = true;
-  }
-
-  @Override
-  public ByteBuffer getOutput() {
-    ByteBuffer outputBuffer = this.outputBuffer;
-    this.outputBuffer = EMPTY_BUFFER;
-    return outputBuffer;
-  }
-
-  @SuppressWarnings("ReferenceEquality")
-  @Override
-  public boolean isEnded() {
-    return inputEnded && outputBuffer == EMPTY_BUFFER;
-  }
-
-  @Override
-  public void flush() {
-    outputBuffer = EMPTY_BUFFER;
-    inputEnded = false;
-  }
-
-  @Override
-  public void reset() {
-    flush();
-    buffer = EMPTY_BUFFER;
-    channelCount = Format.NO_VALUE;
-    sampleRateHz = Format.NO_VALUE;
     outputChannels = null;
     pendingOutputChannels = null;
     active = false;

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

@@ -16,61 +16,30 @@
 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;
 
 /**
  * An {@link AudioProcessor} that converts 24-bit and 32-bit integer PCM audio to 32-bit float PCM
  * audio.
  */
-/* package */ final class FloatResamplingAudioProcessor implements AudioProcessor {
+/* package */ final class FloatResamplingAudioProcessor extends BaseAudioProcessor {
 
   private static final int FLOAT_NAN_AS_INT = Float.floatToIntBits(Float.NaN);
   private static final double PCM_32_BIT_INT_TO_PCM_32_BIT_FLOAT_FACTOR = 1.0 / 0x7FFFFFFF;
 
-  private int sampleRateHz;
-  private int channelCount;
-  @C.PcmEncoding private int sourceEncoding;
-  private ByteBuffer buffer;
-  private ByteBuffer outputBuffer;
-  private boolean inputEnded;
-
-  /** Creates a new audio processor that converts audio data to {@link C#ENCODING_PCM_FLOAT}. */
-  public FloatResamplingAudioProcessor() {
-    sampleRateHz = Format.NO_VALUE;
-    channelCount = Format.NO_VALUE;
-    sourceEncoding = C.ENCODING_INVALID;
-    buffer = EMPTY_BUFFER;
-    outputBuffer = EMPTY_BUFFER;
-  }
-
   @Override
-  public boolean configure(int sampleRateHz, int channelCount, @C.Encoding int encoding)
+  public boolean configure(int sampleRateHz, int channelCount, @C.PcmEncoding int encoding)
       throws UnhandledFormatException {
     if (!Util.isEncodingHighResolutionIntegerPcm(encoding)) {
       throw new UnhandledFormatException(sampleRateHz, channelCount, encoding);
     }
-    if (this.sampleRateHz == sampleRateHz
+    return setInputFormat(sampleRateHz, channelCount, encoding);
-        && this.channelCount == channelCount
-        && sourceEncoding == encoding) {
-      return false;
-    }
-    this.sampleRateHz = sampleRateHz;
-    this.channelCount = channelCount;
-    sourceEncoding = encoding;
-    return true;
   }
 
   @Override
   public boolean isActive() {
-    return Util.isEncodingHighResolutionIntegerPcm(sourceEncoding);
+    return Util.isEncodingHighResolutionIntegerPcm(encoding);
-  }
-
-  @Override
-  public int getOutputChannelCount() {
-    return channelCount;
   }
 
   @Override
@@ -78,24 +47,15 @@ import java.nio.ByteOrder;
     return C.ENCODING_PCM_FLOAT;
   }
 
-  @Override
-  public int getOutputSampleRateHz() {
-    return sampleRateHz;
-  }
-
   @Override
   public void queueInput(ByteBuffer inputBuffer) {
-    boolean isInput32Bit = sourceEncoding == C.ENCODING_PCM_32BIT;
+    boolean isInput32Bit = encoding == C.ENCODING_PCM_32BIT;
     int position = inputBuffer.position();
     int limit = inputBuffer.limit();
     int size = limit - position;
 
     int resampledSize = isInput32Bit ? size : (size / 3) * 4;
-    if (buffer.capacity() < resampledSize) {
+    ByteBuffer buffer = replaceOutputBuffer(resampledSize);
-      buffer = ByteBuffer.allocateDirect(resampledSize).order(ByteOrder.nativeOrder());
-    } else {
-      buffer.clear();
-    }
     if (isInput32Bit) {
       for (int i = position; i < limit; i += 4) {
         int pcm32BitInteger =
@@ -117,40 +77,6 @@ import java.nio.ByteOrder;
 
     inputBuffer.position(inputBuffer.limit());
     buffer.flip();
-    outputBuffer = buffer;
-  }
-
-  @Override
-  public void queueEndOfStream() {
-    inputEnded = true;
-  }
-
-  @Override
-  public ByteBuffer getOutput() {
-    ByteBuffer outputBuffer = this.outputBuffer;
-    this.outputBuffer = EMPTY_BUFFER;
-    return outputBuffer;
-  }
-
-  @SuppressWarnings("ReferenceEquality")
-  @Override
-  public boolean isEnded() {
-    return inputEnded && outputBuffer == EMPTY_BUFFER;
-  }
-
-  @Override
-  public void flush() {
-    outputBuffer = EMPTY_BUFFER;
-    inputEnded = false;
-  }
-
-  @Override
-  public void reset() {
-    flush();
-    sampleRateHz = Format.NO_VALUE;
-    channelCount = Format.NO_VALUE;
-    sourceEncoding = C.ENCODING_INVALID;
-    buffer = EMPTY_BUFFER;
   }
 
   /**

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

@@ -18,45 +18,21 @@ package com.google.android.exoplayer2.audio;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import java.nio.ByteBuffer;
-import java.nio.ByteOrder;
 
 /**
  * An {@link AudioProcessor} that converts 8-bit, 24-bit and 32-bit integer PCM audio to 16-bit
  * integer PCM audio.
  */
-/* package */ final class ResamplingAudioProcessor implements AudioProcessor {
+/* package */ final class ResamplingAudioProcessor extends BaseAudioProcessor {
-
-  private int sampleRateHz;
-  private int channelCount;
-  @C.PcmEncoding private int encoding;
-  private ByteBuffer buffer;
-  private ByteBuffer outputBuffer;
-  private boolean inputEnded;
-
-  /** Creates a new audio processor that converts audio data to {@link C#ENCODING_PCM_16BIT}. */
-  public ResamplingAudioProcessor() {
-    sampleRateHz = Format.NO_VALUE;
-    channelCount = Format.NO_VALUE;
-    encoding = C.ENCODING_INVALID;
-    buffer = EMPTY_BUFFER;
-    outputBuffer = EMPTY_BUFFER;
-  }
 
   @Override
-  public boolean configure(int sampleRateHz, int channelCount, @C.Encoding int encoding)
+  public boolean configure(int sampleRateHz, int channelCount, @C.PcmEncoding int encoding)
       throws UnhandledFormatException {
     if (encoding != C.ENCODING_PCM_8BIT && encoding != C.ENCODING_PCM_16BIT
         && encoding != C.ENCODING_PCM_24BIT && encoding != C.ENCODING_PCM_32BIT) {
       throw new UnhandledFormatException(sampleRateHz, channelCount, encoding);
     }
-    if (this.sampleRateHz == sampleRateHz && this.channelCount == channelCount
+    return setInputFormat(sampleRateHz, channelCount, encoding);
-        && this.encoding == encoding) {
-      return false;
-    }
-    this.sampleRateHz = sampleRateHz;
-    this.channelCount = channelCount;
-    this.encoding = encoding;
-    return true;
   }
 
   @Override
@@ -64,21 +40,11 @@ import java.nio.ByteOrder;
     return encoding != C.ENCODING_INVALID && encoding != C.ENCODING_PCM_16BIT;
   }
 
-  @Override
-  public int getOutputChannelCount() {
-    return channelCount;
-  }
-
   @Override
   public int getOutputEncoding() {
     return C.ENCODING_PCM_16BIT;
   }
 
-  @Override
-  public int getOutputSampleRateHz() {
-    return sampleRateHz;
-  }
-
   @Override
   public void queueInput(ByteBuffer inputBuffer) {
     // Prepare the output buffer.
@@ -105,13 +71,9 @@ import java.nio.ByteOrder;
       default:
         throw new IllegalStateException();
     }
-    if (buffer.capacity() < resampledSize) {
-      buffer = ByteBuffer.allocateDirect(resampledSize).order(ByteOrder.nativeOrder());
-    } else {
-      buffer.clear();
-    }
 
     // Resample the little endian input and update the input/output buffers.
+    ByteBuffer buffer = replaceOutputBuffer(resampledSize);
     switch (encoding) {
       case C.ENCODING_PCM_8BIT:
         // 8->16 bit resampling. Shift each byte from [0, 256) to [-128, 128) and scale up.
@@ -146,40 +108,6 @@ import java.nio.ByteOrder;
     }
     inputBuffer.position(inputBuffer.limit());
     buffer.flip();
-    outputBuffer = buffer;
-  }
-
-  @Override
-  public void queueEndOfStream() {
-    inputEnded = true;
-  }
-
-  @Override
-  public ByteBuffer getOutput() {
-    ByteBuffer outputBuffer = this.outputBuffer;
-    this.outputBuffer = EMPTY_BUFFER;
-    return outputBuffer;
-  }
-
-  @SuppressWarnings("ReferenceEquality")
-  @Override
-  public boolean isEnded() {
-    return inputEnded && outputBuffer == EMPTY_BUFFER;
-  }
-
-  @Override
-  public void flush() {
-    outputBuffer = EMPTY_BUFFER;
-    inputEnded = false;
-  }
-
-  @Override
-  public void reset() {
-    flush();
-    sampleRateHz = Format.NO_VALUE;
-    channelCount = Format.NO_VALUE;
-    encoding = C.ENCODING_INVALID;
-    buffer = EMPTY_BUFFER;
   }
 
 }

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

@@ -17,19 +17,17 @@ package com.google.android.exoplayer2.audio;
 
 import android.support.annotation.IntDef;
 import com.google.android.exoplayer2.C;
-import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.util.Util;
 import java.lang.annotation.Documented;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.nio.ByteBuffer;
-import java.nio.ByteOrder;
 
 /**
  * An {@link AudioProcessor} that skips silence in the input stream. Input and output are 16-bit
  * PCM.
  */
-public final class SilenceSkippingAudioProcessor implements AudioProcessor {
+public final class SilenceSkippingAudioProcessor extends BaseAudioProcessor {
 
   /**
    * The minimum duration of audio that must be below {@link #SILENCE_THRESHOLD_LEVEL} to classify
@@ -70,16 +68,10 @@ public final class SilenceSkippingAudioProcessor implements AudioProcessor {
   /** State when the input is silent. */
   private static final int STATE_SILENT = 2;
 
-  private int channelCount;
-  private int sampleRateHz;
   private int bytesPerFrame;
 
   private boolean enabled;
 
-  private ByteBuffer buffer;
-  private ByteBuffer outputBuffer;
-  private boolean inputEnded;
-
   /**
    * Buffers audio data that may be classified as silence while in {@link #STATE_MAYBE_SILENT}. If
    * the input becomes noisy before the buffer has filled, it will be output. Otherwise, the buffer
@@ -101,10 +93,6 @@ public final class SilenceSkippingAudioProcessor implements AudioProcessor {
 
   /** Creates a new silence trimming audio processor. */
   public SilenceSkippingAudioProcessor() {
-    buffer = EMPTY_BUFFER;
-    outputBuffer = EMPTY_BUFFER;
-    channelCount = Format.NO_VALUE;
-    sampleRateHz = Format.NO_VALUE;
     maybeSilenceBuffer = Util.EMPTY_BYTE_ARRAY;
     paddingBuffer = Util.EMPTY_BYTE_ARRAY;
   }
@@ -131,43 +119,23 @@ public final class SilenceSkippingAudioProcessor implements AudioProcessor {
   // AudioProcessor implementation.
 
   @Override
-  public boolean configure(int sampleRateHz, int channelCount, int encoding)
+  public boolean configure(int sampleRateHz, int channelCount, @C.PcmEncoding int encoding)
       throws UnhandledFormatException {
     if (encoding != C.ENCODING_PCM_16BIT) {
       throw new UnhandledFormatException(sampleRateHz, channelCount, encoding);
     }
-    if (this.sampleRateHz == sampleRateHz && this.channelCount == channelCount) {
-      return false;
-    }
-    this.sampleRateHz = sampleRateHz;
-    this.channelCount = channelCount;
     bytesPerFrame = channelCount * 2;
-    return true;
+    return setInputFormat(sampleRateHz, channelCount, encoding);
   }
 
   @Override
   public boolean isActive() {
-    return sampleRateHz != Format.NO_VALUE && enabled;
+    return super.isActive() && enabled;
-  }
-
-  @Override
-  public int getOutputChannelCount() {
-    return channelCount;
-  }
-
-  @Override
-  public @C.Encoding int getOutputEncoding() {
-    return C.ENCODING_PCM_16BIT;
-  }
-
-  @Override
-  public int getOutputSampleRateHz() {
-    return sampleRateHz;
   }
 
   @Override
   public void queueInput(ByteBuffer inputBuffer) {
-    while (inputBuffer.hasRemaining() && !outputBuffer.hasRemaining()) {
+    while (inputBuffer.hasRemaining() && !hasPendingOutput()) {
       switch (state) {
         case STATE_NOISY:
           processNoisy(inputBuffer);
@@ -185,8 +153,7 @@ public final class SilenceSkippingAudioProcessor implements AudioProcessor {
   }
 
   @Override
-  public void queueEndOfStream() {
+  protected void onQueueEndOfStream() {
-    inputEnded = true;
     if (maybeSilenceBufferSize > 0) {
       // We haven't received enough silence to transition to the silent state, so output the buffer.
       output(maybeSilenceBuffer, maybeSilenceBufferSize);
@@ -197,20 +164,7 @@ public final class SilenceSkippingAudioProcessor implements AudioProcessor {
   }
 
   @Override
-  public ByteBuffer getOutput() {
+  protected void onFlush() {
-    ByteBuffer outputBuffer = this.outputBuffer;
-    this.outputBuffer = EMPTY_BUFFER;
-    return outputBuffer;
-  }
-
-  @SuppressWarnings("ReferenceEquality")
-  @Override
-  public boolean isEnded() {
-    return inputEnded && outputBuffer == EMPTY_BUFFER;
-  }
-
-  @Override
-  public void flush() {
     if (isActive()) {
       int maybeSilenceBufferSize = durationUsToFrames(MINIMUM_SILENCE_DURATION_US) * bytesPerFrame;
       if (maybeSilenceBuffer.length != maybeSilenceBufferSize) {
@@ -222,20 +176,14 @@ public final class SilenceSkippingAudioProcessor implements AudioProcessor {
       }
     }
     state = STATE_NOISY;
-    outputBuffer = EMPTY_BUFFER;
-    inputEnded = false;
     skippedFrames = 0;
     maybeSilenceBufferSize = 0;
     hasOutputNoise = false;
   }
 
   @Override
-  public void reset() {
+  protected void onReset() {
     enabled = false;
-    flush();
-    buffer = EMPTY_BUFFER;
-    channelCount = Format.NO_VALUE;
-    sampleRateHz = Format.NO_VALUE;
     paddingSize = 0;
     maybeSilenceBuffer = Util.EMPTY_BYTE_ARRAY;
     paddingBuffer = Util.EMPTY_BYTE_ARRAY;
@@ -330,30 +278,19 @@ public final class SilenceSkippingAudioProcessor implements AudioProcessor {
    * processor.
    */
   private void output(byte[] data, int length) {
-    prepareForOutput(length);
+    replaceOutputBuffer(length).put(data, 0, length).flip();
-    buffer.put(data, 0, length);
+    if (length > 0) {
-    buffer.flip();
+      hasOutputNoise = true;
-    outputBuffer = buffer;
+    }
   }
 
   /**
    * Copies remaining bytes from {@code data} to populate a new output buffer from the processor.
    */
   private void output(ByteBuffer data) {
-    prepareForOutput(data.remaining());
+    int length = data.remaining();
-    buffer.put(data);
+    replaceOutputBuffer(length).put(data).flip();
-    buffer.flip();
+    if (length > 0) {
-    outputBuffer = buffer;
-  }
-
-  /** Prepares to output {@code size} bytes in {@code buffer}. */
-  private void prepareForOutput(int size) {
-    if (buffer.capacity() < size) {
-      buffer = ByteBuffer.allocateDirect(size).order(ByteOrder.nativeOrder());
-    } else {
-      buffer.clear();
-    }
-    if (size > 0) {
       hasOutputNoise = true;
     }
   }

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

@@ -17,7 +17,6 @@ package com.google.android.exoplayer2.audio;
 
 import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
-import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Log;
 import com.google.android.exoplayer2.util.Util;
@@ -36,13 +35,13 @@ import java.nio.ByteOrder;
  * custom {@link com.google.android.exoplayer2.audio.DefaultAudioSink.AudioProcessorChain} when
  * creating the audio sink, and include this audio processor after all other audio processors.
  */
-public final class TeeAudioProcessor implements AudioProcessor {
+public final class TeeAudioProcessor extends BaseAudioProcessor {
 
   /** A sink for audio buffers handled by the audio processor. */
   public interface AudioBufferSink {
 
     /** Called when the audio processor is flushed with a format of subsequent input. */
-    void flush(int sampleRateHz, int channelCount, @C.Encoding int encoding);
+    void flush(int sampleRateHz, int channelCount, @C.PcmEncoding int encoding);
 
     /**
      * Called when data is written to the audio processor.
@@ -54,14 +53,6 @@ public final class TeeAudioProcessor implements AudioProcessor {
 
   private final AudioBufferSink audioBufferSink;
 
-  private int sampleRateHz;
-  private int channelCount;
-  @C.Encoding private int encoding;
-
-  private ByteBuffer buffer;
-  private ByteBuffer outputBuffer;
-  private boolean inputEnded;
-
   /**
    * Creates a new tee audio processor, sending incoming data to the given {@link AudioBufferSink}.
    *
@@ -70,100 +61,28 @@ public final class TeeAudioProcessor implements AudioProcessor {
    */
   public TeeAudioProcessor(AudioBufferSink audioBufferSink) {
     this.audioBufferSink = Assertions.checkNotNull(audioBufferSink);
-
-    buffer = EMPTY_BUFFER;
-    outputBuffer = EMPTY_BUFFER;
-    channelCount = Format.NO_VALUE;
-    sampleRateHz = Format.NO_VALUE;
   }
 
   @Override
-  public boolean configure(int sampleRateHz, int channelCount, @C.Encoding int encoding) {
+  public boolean configure(int sampleRateHz, int channelCount, @C.PcmEncoding int encoding) {
-    boolean formatChanged =
+    return setInputFormat(sampleRateHz, channelCount, encoding);
-        sampleRateHz != this.sampleRateHz
-            || channelCount != this.channelCount
-            || encoding != this.encoding;
-    this.sampleRateHz = sampleRateHz;
-    this.channelCount = channelCount;
-    this.encoding = encoding;
-    // The sink always needs to be flushed if the format is changing.
-    return formatChanged;
   }
 
   @Override
-  public boolean isActive() {
+  public void queueInput(ByteBuffer inputBuffer) {
-    return sampleRateHz != Format.NO_VALUE;
+    int remaining = inputBuffer.remaining();
-  }
-
-  @Override
-  public int getOutputChannelCount() {
-    return channelCount;
-  }
-
-  @Override
-  public int getOutputEncoding() {
-    return encoding;
-  }
-
-  @Override
-  public int getOutputSampleRateHz() {
-    return sampleRateHz;
-  }
-
-  @Override
-  public void queueInput(ByteBuffer buffer) {
-    int remaining = buffer.remaining();
     if (remaining == 0) {
       return;
     }
+    audioBufferSink.handleBuffer(inputBuffer.asReadOnlyBuffer());
+    replaceOutputBuffer(remaining).put(inputBuffer).flip();
+  }
 
-    audioBufferSink.handleBuffer(buffer.asReadOnlyBuffer());
+  @Override
-
+  protected void onFlush() {
-    if (this.buffer.capacity() < remaining) {
+    if (isActive()) {
-      this.buffer = ByteBuffer.allocateDirect(remaining).order(ByteOrder.nativeOrder());
+      audioBufferSink.flush(sampleRateHz, channelCount, encoding);
-    } else {
-      this.buffer.clear();
     }
-
-    this.buffer.put(buffer);
-
-    this.buffer.flip();
-    outputBuffer = this.buffer;
-  }
-
-  @Override
-  public void queueEndOfStream() {
-    inputEnded = true;
-  }
-
-  @Override
-  public ByteBuffer getOutput() {
-    ByteBuffer outputBuffer = this.outputBuffer;
-    this.outputBuffer = EMPTY_BUFFER;
-    return outputBuffer;
-  }
-
-  @SuppressWarnings("ReferenceEquality")
-  @Override
-  public boolean isEnded() {
-    return inputEnded && outputBuffer == EMPTY_BUFFER;
-  }
-
-  @Override
-  public void flush() {
-    outputBuffer = EMPTY_BUFFER;
-    inputEnded = false;
-
-    audioBufferSink.flush(sampleRateHz, channelCount, encoding);
-  }
-
-  @Override
-  public void reset() {
-    flush();
-    buffer = EMPTY_BUFFER;
-    sampleRateHz = Format.NO_VALUE;
-    channelCount = Format.NO_VALUE;
-    encoding = Format.NO_VALUE;
   }
 
   /**
@@ -188,8 +107,8 @@ public final class TeeAudioProcessor implements AudioProcessor {
 
     private int sampleRateHz;
     private int channelCount;
-    private @C.Encoding int encoding;
+    @C.PcmEncoding private int encoding;
-    private @Nullable RandomAccessFile randomAccessFile;
+    @Nullable private RandomAccessFile randomAccessFile;
     private int counter;
     private int bytesWritten;
 
@@ -205,7 +124,7 @@ public final class TeeAudioProcessor implements AudioProcessor {
     }
 
     @Override
-    public void flush(int sampleRateHz, int channelCount, int encoding) {
+    public void flush(int sampleRateHz, int channelCount, @C.PcmEncoding int encoding) {
       try {
         reset();
       } catch (IOException e) {

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

@@ -16,39 +16,27 @@
 package com.google.android.exoplayer2.audio;
 
 import com.google.android.exoplayer2.C;
-import com.google.android.exoplayer2.C.Encoding;
-import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.util.Util;
 import java.nio.ByteBuffer;
-import java.nio.ByteOrder;
 
 /** Audio processor for trimming samples from the start/end of data. */
-/* package */ final class TrimmingAudioProcessor implements AudioProcessor {
+/* package */ final class TrimmingAudioProcessor extends BaseAudioProcessor {
 
-  @C.Encoding private static final int OUTPUT_ENCODING = C.ENCODING_PCM_16BIT;
+  @C.PcmEncoding private static final int OUTPUT_ENCODING = C.ENCODING_PCM_16BIT;
 
   private boolean isActive;
   private int trimStartFrames;
   private int trimEndFrames;
-  private int channelCount;
-  private int sampleRateHz;
   private int bytesPerFrame;
   private boolean receivedInputSinceConfigure;
 
   private int pendingTrimStartBytes;
-  private ByteBuffer buffer;
-  private ByteBuffer outputBuffer;
   private byte[] endBuffer;
   private int endBufferSize;
-  private boolean inputEnded;
   private long trimmedFrameCount;
 
   /** Creates a new audio processor for trimming samples from the start/end of data. */
   public TrimmingAudioProcessor() {
-    buffer = EMPTY_BUFFER;
-    outputBuffer = EMPTY_BUFFER;
-    channelCount = Format.NO_VALUE;
-    sampleRateHz = Format.NO_VALUE;
     endBuffer = Util.EMPTY_BYTE_ARRAY;
   }
 
@@ -80,7 +68,7 @@ import java.nio.ByteOrder;
   }
 
   @Override
-  public boolean configure(int sampleRateHz, int channelCount, @Encoding int encoding)
+  public boolean configure(int sampleRateHz, int channelCount, @C.PcmEncoding int encoding)
       throws UnhandledFormatException {
     if (encoding != OUTPUT_ENCODING) {
       throw new UnhandledFormatException(sampleRateHz, channelCount, encoding);
@@ -88,8 +76,6 @@ import java.nio.ByteOrder;
     if (endBufferSize > 0) {
       trimmedFrameCount += endBufferSize / bytesPerFrame;
     }
-    this.channelCount = channelCount;
-    this.sampleRateHz = sampleRateHz;
     bytesPerFrame = Util.getPcmFrameSize(OUTPUT_ENCODING, channelCount);
     endBuffer = new byte[trimEndFrames * bytesPerFrame];
     endBufferSize = 0;
@@ -97,6 +83,7 @@ import java.nio.ByteOrder;
     boolean wasActive = isActive;
     isActive = trimStartFrames != 0 || trimEndFrames != 0;
     receivedInputSinceConfigure = false;
+    setInputFormat(sampleRateHz, channelCount, encoding);
     return wasActive != isActive;
   }
 
@@ -105,21 +92,6 @@ import java.nio.ByteOrder;
     return isActive;
   }
 
-  @Override
-  public int getOutputChannelCount() {
-    return channelCount;
-  }
-
-  @Override
-  public int getOutputEncoding() {
-    return OUTPUT_ENCODING;
-  }
-
-  @Override
-  public int getOutputSampleRateHz() {
-    return sampleRateHz;
-  }
-
   @Override
   public void queueInput(ByteBuffer inputBuffer) {
     int position = inputBuffer.position();
@@ -147,11 +119,7 @@ import java.nio.ByteOrder;
     // endBuffer as full as possible, the output should be any surplus bytes currently in endBuffer
     // followed by any surplus bytes in the new inputBuffer.
     int remainingBytesToOutput = endBufferSize + remaining - endBuffer.length;
-    if (buffer.capacity() < remainingBytesToOutput) {
+    ByteBuffer buffer = replaceOutputBuffer(remainingBytesToOutput);
-      buffer = ByteBuffer.allocateDirect(remainingBytesToOutput).order(ByteOrder.nativeOrder());
-    } else {
-      buffer.clear();
-    }
 
     // Output from endBuffer.
     int endBufferBytesToOutput = Util.constrainValue(remainingBytesToOutput, 0, endBufferSize);
@@ -172,48 +140,31 @@ import java.nio.ByteOrder;
     endBufferSize += remaining;
 
     buffer.flip();
-    outputBuffer = buffer;
-  }
-
-  @Override
-  public void queueEndOfStream() {
-    inputEnded = true;
   }
 
   @SuppressWarnings("ReferenceEquality")
   @Override
   public ByteBuffer getOutput() {
-    ByteBuffer outputBuffer = this.outputBuffer;
+    if (super.isEnded() && endBufferSize > 0) {
-    if (inputEnded && endBufferSize > 0 && outputBuffer == EMPTY_BUFFER) {
       // Because audio processors may be drained in the middle of the stream we assume that the
       // contents of the end buffer need to be output. Gapless transitions don't involve a call to
       // queueEndOfStream so won't be affected. When audio is actually ending we play the padding
       // data which is incorrect. This behavior can be fixed once we have the timestamps associated
       // with input buffers.
-      if (buffer.capacity() < endBufferSize) {
+      replaceOutputBuffer(endBufferSize).put(endBuffer, 0, endBufferSize).flip();
-        buffer = ByteBuffer.allocateDirect(endBufferSize).order(ByteOrder.nativeOrder());
-      } else {
-        buffer.clear();
-      }
-      buffer.put(endBuffer, 0, endBufferSize);
       endBufferSize = 0;
-      buffer.flip();
-      outputBuffer = buffer;
     }
-    this.outputBuffer = EMPTY_BUFFER;
+    return super.getOutput();
-    return outputBuffer;
   }
 
   @SuppressWarnings("ReferenceEquality")
   @Override
   public boolean isEnded() {
-    return inputEnded && endBufferSize == 0 && outputBuffer == EMPTY_BUFFER;
+    return super.isEnded() && endBufferSize == 0;
   }
 
   @Override
-  public void flush() {
+  protected void onFlush() {
-    outputBuffer = EMPTY_BUFFER;
-    inputEnded = false;
     if (receivedInputSinceConfigure) {
       // Audio processors are flushed after initial configuration, so we leave the pending trim
       // start byte count unmodified if the processor was just configured. Otherwise we (possibly
@@ -226,11 +177,7 @@ import java.nio.ByteOrder;
   }
 
   @Override
-  public void reset() {
+  protected void onReset() {
-    flush();
-    buffer = EMPTY_BUFFER;
-    channelCount = Format.NO_VALUE;
-    sampleRateHz = Format.NO_VALUE;
     endBuffer = Util.EMPTY_BYTE_ARRAY;
   }