content: /*
   * Copyright 2002-2019 Drew Noakes and contributors
   *
   *    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
   *
   *        https://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.
   *
   * More information about this project is available at:
   *
   *    https://drewnoakes.com/code/exif/
   *    https://github.com/drewnoakes/metadata-extractor
   */
  package com.drew.metadata.mp4.media;
  
  import com.drew.lang.SequentialReader;
  import com.drew.lang.annotations.NotNull;
  import com.drew.metadata.Metadata;
  import com.drew.metadata.mp4.Mp4BoxTypes;
  import com.drew.metadata.mp4.Mp4Context;
  import com.drew.metadata.mp4.Mp4Dictionary;
  import com.drew.metadata.mp4.Mp4MediaHandler;
  
  import java.io.IOException;
  
  public class Mp4SoundHandler extends Mp4MediaHandler<Mp4SoundDirectory>
  {
      public Mp4SoundHandler(Metadata metadata, Mp4Context context)
      {
          super(metadata, context);
      }
  
      @NotNull
      @Override
      protected Mp4SoundDirectory getDirectory()
      {
          return new Mp4SoundDirectory();
      }
  
      @Override
      protected String getMediaInformation()
      {
          return Mp4BoxTypes.BOX_SOUND_MEDIA_INFO;
      }
  
      @Override
      public void processSampleDescription(@NotNull SequentialReader reader) throws IOException
      {
          // ISO/IED 14496-12:2015 pg.7
  
          reader.skip(4); // one byte version, three bytes flags
  
          // ISO/IED 14496-12:2015 pg.33
  
          long numberOfEntries = reader.getUInt32();
          long sampleDescriptionSize = reader.getUInt32();
          String format = reader.getString(4);
          reader.skip(6); // Reserved
          int dataReferenceIndex = reader.getUInt16();
  
          // ISO/IED 14496-12:2015 pg.161
  
          reader.skip(8); // Reserved
          int channelCount = reader.getUInt16();
          int sampleSize = reader.getInt16();
          reader.skip(2); // Pre-defined
          reader.skip(2); // Reserved
          long sampleRate = reader.getUInt32();
          // ChannelLayout()
          // DownMix and/or DRC boxes
          // More boxes as needed
  
          // TODO review this
          Mp4Dictionary.setLookup(Mp4SoundDirectory.TAG_AUDIO_FORMAT, format, directory);
  
          directory.setInt(Mp4SoundDirectory.TAG_NUMBER_OF_CHANNELS, channelCount);
          directory.setInt(Mp4SoundDirectory.TAG_AUDIO_SAMPLE_SIZE, sampleSize);
      }
  
      @Override
      public void processMediaInformation(@NotNull SequentialReader reader) throws IOException
      {
          // ISO/IED 14496-12:2015 pg.7
  
          reader.skip(4); // one byte version, three bytes flags
  
          // ISO/IED 14496-12:2015 pg.159
  
          int balance = reader.getInt16();
          reader.skip(2); // Reserved
  
          double integer = balance & 0xFFFF0000;
          double fraction = (balance & 0x0000FFFF) / Math.pow(2, 4);
          directory.setDouble(Mp4SoundDirectory.TAG_SOUND_BALANCE, integer + fraction);
      }
  
      @Override
      protected void processTimeToSample(@NotNull SequentialReader reader, Mp4Context context) throws IOException
      {
          // ISO/IED 14496-12:2015 pg.7
  
          reader.skip(4); // one byte version, three bytes flags
  
          // ISO/IED 14496-12:2015 pg.37
  
          long entryCount = reader.getUInt32();
  
          // skip entries (4 bytes sample count, 4 bytes sample delta, per entry)
          reader.skip(entryCount * 8);
  
          if (context.timeScale != null) {
              directory.setDouble(Mp4SoundDirectory.TAG_AUDIO_SAMPLE_RATE, context.timeScale);
          }
      }
  }
  