Add TrimmingAudioProcessor for gapless

Remove gapless functionality that relies on MediaCodec, and implement this in
an AudioProcessor instead.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=168547487

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

@@ -529,8 +529,6 @@ public final class Format implements Parcelable {
     maybeSetIntegerV16(format, "rotation-degrees", rotationDegrees);
     maybeSetIntegerV16(format, MediaFormat.KEY_CHANNEL_COUNT, channelCount);
     maybeSetIntegerV16(format, MediaFormat.KEY_SAMPLE_RATE, sampleRate);
-    maybeSetIntegerV16(format, "encoder-delay", encoderDelay);
-    maybeSetIntegerV16(format, "encoder-padding", encoderPadding);
     for (int i = 0; i < initializationData.size(); i++) {
       format.setByteBuffer("csd-" + i, ByteBuffer.wrap(initializationData.get(i)));
     }

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

@@ -40,21 +40,23 @@ import java.util.LinkedList;
  * playback position smoothing, non-blocking writes and reconfiguration.
  * <p>
  * Before starting playback, specify the input format by calling
- * {@link #configure(String, int, int, int, int)}. Optionally call {@link #setAudioSessionId(int)},
- * {@link #setAudioAttributes(AudioAttributes)}, {@link #enableTunnelingV21(int)} and
- * {@link #disableTunneling()} to configure audio playback. These methods may be called after
- * writing data to the track, in which case it will be reinitialized as required.
+ * {@link #configure(String, int, int, int, int, int[], int, int)}. Optionally call
+ * {@link #setAudioSessionId(int)}, {@link #setAudioAttributes(AudioAttributes)},
+ * {@link #enableTunnelingV21(int)} and {@link #disableTunneling()} to configure audio playback.
+ * These methods may be called after writing data to the track, in which case it will be
+ * reinitialized as required.
  * <p>
  * Call {@link #handleBuffer(ByteBuffer, long)} to write data, and {@link #handleDiscontinuity()}
  * when the data being fed is discontinuous. Call {@link #play()} to start playing the written data.
  * <p>
- * Call {@link #configure(String, int, int, int, int)} whenever the input format changes. The track
- * will be reinitialized on the next call to {@link #handleBuffer(ByteBuffer, long)}.
+ * Call {@link #configure(String, int, int, int, int, int[], int, int)} whenever the input format
+ * changes. The track will be reinitialized on the next call to
+ * {@link #handleBuffer(ByteBuffer, long)}.
  * <p>
  * Calling {@link #reset()} releases the underlying {@link android.media.AudioTrack} (and so does
- * calling {@link #configure(String, int, int, int, int)} unless the format is unchanged). It is
- * safe to call {@link #handleBuffer(ByteBuffer, long)} after {@link #reset()} without calling
- * {@link #configure(String, int, int, int, int)}.
+ * calling {@link #configure(String, int, int, int, int, int[], int, int)} unless the format is
+ * unchanged). It is safe to call {@link #handleBuffer(ByteBuffer, long)} after {@link #reset()}
+ * without calling {@link #configure(String, int, int, int, int, int[], int, int)}.
  * <p>
  * Call {@link #playToEndOfStream()} repeatedly to play out all data when no more input buffers will
  * be provided via {@link #handleBuffer(ByteBuffer, long)} until the next {@link #reset}. Call
@@ -280,6 +282,7 @@ public final class AudioTrack {
 
   @Nullable private final AudioCapabilities audioCapabilities;
   private final ChannelMappingAudioProcessor channelMappingAudioProcessor;
+  private final TrimmingAudioProcessor trimmingAudioProcessor;
   private final SonicAudioProcessor sonicAudioProcessor;
   private final AudioProcessor[] availableAudioProcessors;
   private final Listener listener;
@@ -375,12 +378,14 @@ public final class AudioTrack {
       audioTrackUtil = new AudioTrackUtil();
     }
     channelMappingAudioProcessor = new ChannelMappingAudioProcessor();
+    trimmingAudioProcessor = new TrimmingAudioProcessor();
     sonicAudioProcessor = new SonicAudioProcessor();
-    availableAudioProcessors = new AudioProcessor[3 + audioProcessors.length];
+    availableAudioProcessors = new AudioProcessor[4 + audioProcessors.length];
     availableAudioProcessors[0] = new ResamplingAudioProcessor();
     availableAudioProcessors[1] = channelMappingAudioProcessor;
-    System.arraycopy(audioProcessors, 0, availableAudioProcessors, 2, audioProcessors.length);
-    availableAudioProcessors[2 + audioProcessors.length] = sonicAudioProcessor;
+    availableAudioProcessors[2] = trimmingAudioProcessor;
+    System.arraycopy(audioProcessors, 0, availableAudioProcessors, 3, audioProcessors.length);
+    availableAudioProcessors[3 + audioProcessors.length] = sonicAudioProcessor;
     playheadOffsets = new long[MAX_PLAYHEAD_OFFSET_COUNT];
     volume = 1.0f;
     startMediaTimeState = START_NOT_SET;
@@ -450,24 +455,6 @@ public final class AudioTrack {
     return startMediaTimeUs + applySpeedup(positionUs);
   }
 
-  /**
-   * Configures (or reconfigures) the audio track.
-   *
-   * @param mimeType The mime type.
-   * @param channelCount The number of channels.
-   * @param sampleRate The sample rate in Hz.
-   * @param pcmEncoding For PCM formats, the encoding used. One of {@link C#ENCODING_PCM_16BIT},
-   *     {@link C#ENCODING_PCM_16BIT}, {@link C#ENCODING_PCM_24BIT} and
-   *     {@link C#ENCODING_PCM_32BIT}.
-   * @param specifiedBufferSize A specific size for the playback buffer in bytes, or 0 to infer a
-   *     suitable buffer size automatically.
-   * @throws ConfigurationException If an error occurs configuring the track.
-   */
-  public void configure(String mimeType, int channelCount, int sampleRate,
-      @C.PcmEncoding int pcmEncoding, int specifiedBufferSize) throws ConfigurationException {
-    configure(mimeType, channelCount, sampleRate, pcmEncoding, specifiedBufferSize, null);
-  }
-
   /**
    * Configures (or reconfigures) the audio track.
    *
@@ -484,16 +471,22 @@ public final class AudioTrack {
    *     input unchanged. Otherwise, the element at index {@code i} specifies index of the input
    *     channel to map to output channel {@code i} when preprocessing input buffers. After the
    *     map is applied the audio data will have {@code outputChannels.length} channels.
+   * @param trimStartSamples The number of audio samples to trim from the start of data written to
+   *     the track after this call.
+   * @param trimEndSamples The number of audio samples to trim from data written to the track
+   *     immediately preceding the next call to {@link #reset()} or
+   *     {@link #configure(String, int, int, int, int, int[], int, int)}.
    * @throws ConfigurationException If an error occurs configuring the track.
    */
   public void configure(String mimeType, int channelCount, int sampleRate,
-      @C.PcmEncoding int pcmEncoding, int specifiedBufferSize, int[] outputChannels)
-      throws ConfigurationException {
+      @C.PcmEncoding int pcmEncoding, int specifiedBufferSize, @Nullable int[] outputChannels,
+      int trimStartSamples, int trimEndSamples) throws ConfigurationException {
     boolean passthrough = !MimeTypes.AUDIO_RAW.equals(mimeType);
     @C.Encoding int encoding = passthrough ? getEncodingForMimeType(mimeType) : pcmEncoding;
     boolean flush = false;
     if (!passthrough) {
       pcmFrameSize = Util.getPcmFrameSize(pcmEncoding, channelCount);
+      trimmingAudioProcessor.setTrimSampleCount(trimStartSamples, trimEndSamples);
       channelMappingAudioProcessor.setChannelMap(outputChannels);
       for (AudioProcessor audioProcessor : availableAudioProcessors) {
         try {
@@ -689,7 +682,8 @@ public final class AudioTrack {
    * Returns whether the data was handled in full. If the data was not handled in full then the same
    * {@link ByteBuffer} must be provided to subsequent calls until it has been fully consumed,
    * except in the case of an interleaving call to {@link #reset()} (or an interleaving call to
-   * {@link #configure(String, int, int, int, int)} that caused the track to be reset).
+   * {@link #configure(String, int, int, int, int, int[], int, int)} that caused the track to be
+   * reset).
    *
    * @param buffer The buffer containing audio data.
    * @param presentationTimeUs The presentation timestamp of the buffer in microseconds.

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

@@ -52,7 +52,7 @@ import java.util.Arrays;
    * Resets the channel mapping. After calling this method, call {@link #configure(int, int, int)}
    * to start using the new channel map.
    *
-   * @see AudioTrack#configure(String, int, int, int, int, int[])
+   * @see AudioTrack#configure(String, int, int, int, int, int[], int, int)
    */
   public void setChannelMap(int[] outputChannels) {
     pendingOutputChannels = outputChannels;

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

@@ -53,6 +53,8 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
   private android.media.MediaFormat passthroughMediaFormat;
   private int pcmEncoding;
   private int channelCount;
+  private int encoderDelay;
+  private int encoderPadding;
   private long currentPositionUs;
   private boolean allowPositionDiscontinuity;
 
@@ -134,8 +136,8 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
       @Nullable AudioRendererEventListener eventListener,
       @Nullable AudioCapabilities audioCapabilities, AudioProcessor... audioProcessors) {
     super(C.TRACK_TYPE_AUDIO, mediaCodecSelector, drmSessionManager, playClearSamplesWithoutKeys);
-    audioTrack = new AudioTrack(audioCapabilities, audioProcessors, new AudioTrackListener());
     eventDispatcher = new EventDispatcher(eventHandler, eventListener);
+    audioTrack = new AudioTrack(audioCapabilities, audioProcessors, new AudioTrackListener());
   }
 
   @Override
@@ -240,6 +242,8 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
     pcmEncoding = MimeTypes.AUDIO_RAW.equals(newFormat.sampleMimeType) ? newFormat.pcmEncoding
         : C.ENCODING_PCM_16BIT;
     channelCount = newFormat.channelCount;
+    encoderDelay = newFormat.encoderDelay != Format.NO_VALUE ? newFormat.encoderDelay : 0;
+    encoderPadding = newFormat.encoderPadding != Format.NO_VALUE ? newFormat.encoderPadding : 0;
   }
 
   @Override
@@ -262,7 +266,8 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
     }
 
     try {
-      audioTrack.configure(mimeType, channelCount, sampleRate, pcmEncoding, 0, channelMap);
+      audioTrack.configure(mimeType, channelCount, sampleRate, pcmEncoding, 0, channelMap,
+          encoderDelay, encoderPadding);
     } catch (AudioTrack.ConfigurationException e) {
       throw ExoPlaybackException.createForRenderer(e, getIndex());
     }

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

@@ -78,6 +78,8 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
 
   private DecoderCounters decoderCounters;
   private Format inputFormat;
+  private int encoderDelay;
+  private int encoderPadding;
   private SimpleDecoder<DecoderInputBuffer, ? extends SimpleOutputBuffer,
         ? extends AudioDecoderException> decoder;
   private DecoderInputBuffer inputBuffer;
@@ -308,7 +310,7 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
     if (audioTrackNeedsConfigure) {
       Format outputFormat = getOutputFormat();
       audioTrack.configure(outputFormat.sampleMimeType, outputFormat.channelCount,
-          outputFormat.sampleRate, outputFormat.pcmEncoding, 0);
+          outputFormat.sampleRate, outputFormat.pcmEncoding, 0, null, encoderDelay, encoderPadding);
       audioTrackNeedsConfigure = false;
     }
 
@@ -587,6 +589,9 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
       audioTrackNeedsConfigure = true;
     }
 
+    encoderDelay = newFormat.encoderDelay == Format.NO_VALUE ? 0 : newFormat.encoderDelay;
+    encoderPadding = newFormat.encoderPadding == Format.NO_VALUE ? 0 : newFormat.encoderPadding;
+
     eventDispatcher.inputFormatChanged(newFormat);
   }
 

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

@@ -0,0 +1,180 @@
+/*
+ * Copyright (C) 2017 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 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 {
+
+  private boolean isActive;
+  private int trimStartSamples;
+  private int trimEndSamples;
+  private int channelCount;
+
+  private int pendingTrimStartBytes;
+  private ByteBuffer buffer;
+  private ByteBuffer outputBuffer;
+  private byte[] endBuffer;
+  private int endBufferSize;
+  private boolean inputEnded;
+
+  /**
+   * 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;
+  }
+
+  /**
+   * Sets the number of audio samples to trim from the start and end of audio passed to this
+   * processor. After calling this method, call {@link #configure(int, int, int)} to apply the new
+   * trimming sample counts.
+   *
+   * @param trimStartSamples The number of audio samples to trim from the start of audio.
+   * @param trimEndSamples The number of audio samples to trim from the end of audio.
+   * @see AudioTrack#configure(String, int, int, int, int, int[], int, int)
+   */
+  public void setTrimSampleCount(int trimStartSamples, int trimEndSamples) {
+    this.trimStartSamples = trimStartSamples;
+    this.trimEndSamples = trimEndSamples;
+  }
+
+  @Override
+  public boolean configure(int sampleRateHz, int channelCount, @Encoding int encoding)
+      throws UnhandledFormatException {
+    if (encoding != C.ENCODING_PCM_16BIT) {
+      throw new UnhandledFormatException(sampleRateHz, channelCount, encoding);
+    }
+    this.channelCount = channelCount;
+    endBuffer = new byte[trimEndSamples * channelCount * 2];
+    endBufferSize = 0;
+    pendingTrimStartBytes = trimStartSamples * channelCount * 2;
+    boolean wasActive = isActive;
+    isActive = trimStartSamples != 0 || trimEndSamples != 0;
+    return wasActive != isActive;
+  }
+
+  @Override
+  public boolean isActive() {
+    return isActive;
+  }
+
+  @Override
+  public int getOutputChannelCount() {
+    return channelCount;
+  }
+
+  @Override
+  public int getOutputEncoding() {
+    return C.ENCODING_PCM_16BIT;
+  }
+
+  @Override
+  public void queueInput(ByteBuffer inputBuffer) {
+    int position = inputBuffer.position();
+    int limit = inputBuffer.limit();
+    int remaining = limit - position;
+
+    // Trim any pending start bytes from the input buffer.
+    int trimBytes = Math.min(remaining, pendingTrimStartBytes);
+    pendingTrimStartBytes -= trimBytes;
+    inputBuffer.position(position + trimBytes);
+    if (pendingTrimStartBytes > 0) {
+      // Nothing to output yet.
+      return;
+    }
+    remaining -= trimBytes;
+
+    // endBuffer must be kept as full as possible, so that we trim the right amount of media if we
+    // don't receive any more input. After taking into account the number of bytes needed to keep
+    // 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) {
+      buffer = ByteBuffer.allocateDirect(remainingBytesToOutput).order(ByteOrder.nativeOrder());
+    } else {
+      buffer.clear();
+    }
+
+    // Output from endBuffer.
+    int endBufferBytesToOutput = Util.constrainValue(remainingBytesToOutput, 0, endBufferSize);
+    buffer.put(endBuffer, 0, endBufferBytesToOutput);
+    remainingBytesToOutput -= endBufferBytesToOutput;
+
+    // Output from inputBuffer, restoring its limit afterwards.
+    int inputBufferBytesToOutput = Util.constrainValue(remainingBytesToOutput, 0, remaining);
+    inputBuffer.limit(inputBuffer.position() + inputBufferBytesToOutput);
+    buffer.put(inputBuffer);
+    inputBuffer.limit(limit);
+    remaining -= inputBufferBytesToOutput;
+
+    // Compact endBuffer, then repopulate it using the new input.
+    endBufferSize -= endBufferBytesToOutput;
+    System.arraycopy(endBuffer, endBufferBytesToOutput, endBuffer, 0, endBufferSize);
+    inputBuffer.get(endBuffer, endBufferSize, remaining);
+    endBufferSize += remaining;
+
+    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;
+    // It's no longer necessary to trim any media from the start, but it is necessary to clear the
+    // end buffer and refill it.
+    pendingTrimStartBytes = 0;
+    endBufferSize = 0;
+  }
+
+  @Override
+  public void reset() {
+    flush();
+    buffer = EMPTY_BUFFER;
+    channelCount = Format.NO_VALUE;
+    endBuffer = null;
+  }
+
+}