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.flv;
  
  import android.util.Pair;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.Format;
  import com.google.android.exoplayer2.ParserException;
  import com.google.android.exoplayer2.extractor.TrackOutput;
  import com.google.android.exoplayer2.util.CodecSpecificDataUtil;
  import com.google.android.exoplayer2.util.MimeTypes;
  import com.google.android.exoplayer2.util.ParsableByteArray;
  import java.util.Collections;
  
  /**
   * Parses audio tags from an FLV stream and extracts AAC frames.
   */
  /* package */ final class AudioTagPayloadReader extends TagPayloadReader {
  
    private static final int AUDIO_FORMAT_MP3 = 2;
    private static final int AUDIO_FORMAT_ALAW = 7;
    private static final int AUDIO_FORMAT_ULAW = 8;
    private static final int AUDIO_FORMAT_AAC = 10;
  
    private static final int AAC_PACKET_TYPE_SEQUENCE_HEADER = 0;
    private static final int AAC_PACKET_TYPE_AAC_RAW = 1;
  
    private static final int[] AUDIO_SAMPLING_RATE_TABLE = new int[] {5512, 11025, 22050, 44100};
  
    // State variables
    private boolean hasParsedAudioDataHeader;
    private boolean hasOutputFormat;
    private int audioFormat;
  
    public AudioTagPayloadReader(TrackOutput output) {
      super(output);
    }
  
    @Override
    public void seek() {
      // Do nothing.
    }
  
    @Override
    protected boolean parseHeader(ParsableByteArray data) throws UnsupportedFormatException {
      if (!hasParsedAudioDataHeader) {
        int header = data.readUnsignedByte();
        audioFormat = (header >> 4) & 0x0F;
        if (audioFormat == AUDIO_FORMAT_MP3) {
          int sampleRateIndex = (header >> 2) & 0x03;
          int sampleRate = AUDIO_SAMPLING_RATE_TABLE[sampleRateIndex];
          Format format = Format.createAudioSampleFormat(null, MimeTypes.AUDIO_MPEG, null,
              Format.NO_VALUE, Format.NO_VALUE, 1, sampleRate, null, null, 0, null);
          output.format(format);
          hasOutputFormat = true;
        } else if (audioFormat == AUDIO_FORMAT_ALAW || audioFormat == AUDIO_FORMAT_ULAW) {
          String type = audioFormat == AUDIO_FORMAT_ALAW ? MimeTypes.AUDIO_ALAW
              : MimeTypes.AUDIO_MLAW;
          int pcmEncoding = (header & 0x01) == 1 ? C.ENCODING_PCM_16BIT : C.ENCODING_PCM_8BIT;
          Format format = Format.createAudioSampleFormat(null, type, null, Format.NO_VALUE,
              Format.NO_VALUE, 1, 8000, pcmEncoding, null, null, 0, null);
          output.format(format);
          hasOutputFormat = true;
        } else if (audioFormat != AUDIO_FORMAT_AAC) {
          throw new UnsupportedFormatException("Audio format not supported: " + audioFormat);
        }
        hasParsedAudioDataHeader = true;
      } else {
        // Skip header if it was parsed previously.
        data.skipBytes(1);
      }
      return true;
    }
  
    @Override
    protected void parsePayload(ParsableByteArray data, long timeUs) throws ParserException {
      if (audioFormat == AUDIO_FORMAT_MP3) {
        int sampleSize = data.bytesLeft();
        output.sampleData(data, sampleSize);
        output.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
      } else {
        int packetType = data.readUnsignedByte();
        if (packetType == AAC_PACKET_TYPE_SEQUENCE_HEADER && !hasOutputFormat) {
          // Parse the sequence header.
          byte[] audioSpecificConfig = new byte[data.bytesLeft()];
          data.readBytes(audioSpecificConfig, 0, audioSpecificConfig.length);
          Pair<Integer, Integer> audioParams = CodecSpecificDataUtil.parseAacAudioSpecificConfig(
              audioSpecificConfig);
          Format format = Format.createAudioSampleFormat(null, MimeTypes.AUDIO_AAC, null,
              Format.NO_VALUE, Format.NO_VALUE, audioParams.second, audioParams.first,
              Collections.singletonList(audioSpecificConfig), null, 0, null);
          output.format(format);
          hasOutputFormat = true;
        } else if (audioFormat != AUDIO_FORMAT_AAC || packetType == AAC_PACKET_TYPE_AAC_RAW) {
          int sampleSize = data.bytesLeft();
          output.sampleData(data, sampleSize);
          output.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
        }
      }
    }
  
  }
  