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.video;
  
  import com.google.android.exoplayer2.Format;
  import com.google.android.exoplayer2.ParserException;
  import com.google.android.exoplayer2.util.CodecSpecificDataUtil;
  import com.google.android.exoplayer2.util.NalUnitUtil;
  import com.google.android.exoplayer2.util.NalUnitUtil.SpsData;
  import com.google.android.exoplayer2.util.ParsableByteArray;
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * AVC configuration data.
   */
  public final class AvcConfig {
  
    public final List<byte[]> initializationData;
    public final int nalUnitLengthFieldLength;
    public final int width;
    public final int height;
    public final float pixelWidthAspectRatio;
  
    /**
     * Parses AVC configuration data.
     *
     * @param data A {@link ParsableByteArray}, whose position is set to the start of the AVC
     *     configuration data to parse.
     * @return A parsed representation of the HEVC configuration data.
     * @throws ParserException If an error occurred parsing the data.
     */
    public static AvcConfig parse(ParsableByteArray data) throws ParserException {
      try {
        data.skipBytes(4); // Skip to the AVCDecoderConfigurationRecord (defined in 14496-15)
        int nalUnitLengthFieldLength = (data.readUnsignedByte() & 0x3) + 1;
        if (nalUnitLengthFieldLength == 3) {
          throw new IllegalStateException();
        }
        List<byte[]> initializationData = new ArrayList<>();
        int numSequenceParameterSets = data.readUnsignedByte() & 0x1F;
        for (int j = 0; j < numSequenceParameterSets; j++) {
          initializationData.add(buildNalUnitForChild(data));
        }
        int numPictureParameterSets = data.readUnsignedByte();
        for (int j = 0; j < numPictureParameterSets; j++) {
          initializationData.add(buildNalUnitForChild(data));
        }
  
        int width = Format.NO_VALUE;
        int height = Format.NO_VALUE;
        float pixelWidthAspectRatio = 1;
        if (numSequenceParameterSets > 0) {
          byte[] sps = initializationData.get(0);
          SpsData spsData = NalUnitUtil.parseSpsNalUnit(initializationData.get(0),
              nalUnitLengthFieldLength, sps.length);
          width = spsData.width;
          height = spsData.height;
          pixelWidthAspectRatio = spsData.pixelWidthAspectRatio;
        }
        return new AvcConfig(initializationData, nalUnitLengthFieldLength, width, height,
            pixelWidthAspectRatio);
      } catch (ArrayIndexOutOfBoundsException e) {
        throw new ParserException("Error parsing AVC config", e);
      }
    }
  
    private AvcConfig(List<byte[]> initializationData, int nalUnitLengthFieldLength,
        int width, int height, float pixelWidthAspectRatio) {
      this.initializationData = initializationData;
      this.nalUnitLengthFieldLength = nalUnitLengthFieldLength;
      this.width = width;
      this.height = height;
      this.pixelWidthAspectRatio = pixelWidthAspectRatio;
    }
  
    private static byte[] buildNalUnitForChild(ParsableByteArray data) {
      int length = data.readUnsignedShort();
      int offset = data.getPosition();
      data.skipBytes(length);
      return CodecSpecificDataUtil.buildNalUnit(data.data, offset, length);
    }
  
  }
  