content: /*
   * Copyright (C) 2016 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.extractor.wav;
  
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.Format;
  import com.google.android.exoplayer2.ParserException;
  import com.google.android.exoplayer2.extractor.Extractor;
  import com.google.android.exoplayer2.extractor.ExtractorInput;
  import com.google.android.exoplayer2.extractor.ExtractorOutput;
  import com.google.android.exoplayer2.extractor.ExtractorsFactory;
  import com.google.android.exoplayer2.extractor.PositionHolder;
  import com.google.android.exoplayer2.extractor.TrackOutput;
  import com.google.android.exoplayer2.util.MimeTypes;
  import java.io.IOException;
  
  /**
   * Extracts data from WAV byte streams.
   */
  public final class WavExtractor implements Extractor {
  
    /**
     * Factory for {@link WavExtractor} instances.
     */
    public static final ExtractorsFactory FACTORY = new ExtractorsFactory() {
  
      @Override
      public Extractor[] createExtractors() {
        return new Extractor[] {new WavExtractor()};
      }
  
    };
  
    /** Arbitrary maximum input size of 32KB, which is ~170ms of 16-bit stereo PCM audio at 48KHz. */
    private static final int MAX_INPUT_SIZE = 32 * 1024;
  
    private ExtractorOutput extractorOutput;
    private TrackOutput trackOutput;
    private WavHeader wavHeader;
    private int bytesPerFrame;
    private int pendingBytes;
  
    @Override
    public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
      return WavHeaderReader.peek(input) != null;
    }
  
    @Override
    public void init(ExtractorOutput output) {
      extractorOutput = output;
      trackOutput = output.track(0, C.TRACK_TYPE_AUDIO);
      wavHeader = null;
      output.endTracks();
    }
  
    @Override
    public void seek(long position, long timeUs) {
      pendingBytes = 0;
    }
  
    @Override
    public void release() {
      // Do nothing
    }
  
    @Override
    public int read(ExtractorInput input, PositionHolder seekPosition)
        throws IOException, InterruptedException {
      if (wavHeader == null) {
        wavHeader = WavHeaderReader.peek(input);
        if (wavHeader == null) {
          // Should only happen if the media wasn't sniffed.
          throw new ParserException("Unsupported or unrecognized wav header.");
        }
        Format format = Format.createAudioSampleFormat(null, MimeTypes.AUDIO_RAW, null,
            wavHeader.getBitrate(), MAX_INPUT_SIZE, wavHeader.getNumChannels(),
            wavHeader.getSampleRateHz(), wavHeader.getEncoding(), null, null, 0, null);
        trackOutput.format(format);
        bytesPerFrame = wavHeader.getBytesPerFrame();
      }
  
      if (!wavHeader.hasDataBounds()) {
        WavHeaderReader.skipToData(input, wavHeader);
        extractorOutput.seekMap(wavHeader);
      }
  
      int bytesAppended = trackOutput.sampleData(input, MAX_INPUT_SIZE - pendingBytes, true);
      if (bytesAppended != RESULT_END_OF_INPUT) {
        pendingBytes += bytesAppended;
      }
  
      // Samples must consist of a whole number of frames.
      int pendingFrames = pendingBytes / bytesPerFrame;
      if (pendingFrames > 0) {
        long timeUs = wavHeader.getTimeUs(input.getPosition() - pendingBytes);
        int size = pendingFrames * bytesPerFrame;
        pendingBytes -= size;
        trackOutput.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, size, pendingBytes, null);
      }
  
      return bytesAppended == RESULT_END_OF_INPUT ? RESULT_END_OF_INPUT : RESULT_CONTINUE;
    }
  
  }
  