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.mp4;
  
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.util.Util;
  
  /**
   * Rechunks fixed sample size media in which every sample is a key frame (e.g. uncompressed audio).
   */
  /* package */ final class FixedSampleSizeRechunker {
  
    /**
     * The result of a rechunking operation.
     */
    public static final class Results {
  
      public final long[] offsets;
      public final int[] sizes;
      public final int maximumSize;
      public final long[] timestamps;
      public final int[] flags;
      public final long duration;
  
      private Results(
          long[] offsets,
          int[] sizes,
          int maximumSize,
          long[] timestamps,
          int[] flags,
          long duration) {
        this.offsets = offsets;
        this.sizes = sizes;
        this.maximumSize = maximumSize;
        this.timestamps = timestamps;
        this.flags = flags;
        this.duration = duration;
      }
  
    }
  
    /**
     * Maximum number of bytes for each buffer in rechunked output.
     */
    private static final int MAX_SAMPLE_SIZE = 8 * 1024;
  
    /**
     * Rechunk the given fixed sample size input to produce a new sequence of samples.
     *
     * @param fixedSampleSize Size in bytes of each sample.
     * @param chunkOffsets Chunk offsets in the MP4 stream to rechunk.
     * @param chunkSampleCounts Sample counts for each of the MP4 stream's chunks.
     * @param timestampDeltaInTimeUnits Timestamp delta between each sample in time units.
     */
    public static Results rechunk(int fixedSampleSize, long[] chunkOffsets, int[] chunkSampleCounts,
        long timestampDeltaInTimeUnits) {
      int maxSampleCount = MAX_SAMPLE_SIZE / fixedSampleSize;
  
      // Count the number of new, rechunked buffers.
      int rechunkedSampleCount = 0;
      for (int chunkSampleCount : chunkSampleCounts) {
        rechunkedSampleCount += Util.ceilDivide(chunkSampleCount, maxSampleCount);
      }
  
      long[] offsets = new long[rechunkedSampleCount];
      int[] sizes = new int[rechunkedSampleCount];
      int maximumSize = 0;
      long[] timestamps = new long[rechunkedSampleCount];
      int[] flags = new int[rechunkedSampleCount];
  
      int originalSampleIndex = 0;
      int newSampleIndex = 0;
      for (int chunkIndex = 0; chunkIndex < chunkSampleCounts.length; chunkIndex++) {
        int chunkSamplesRemaining = chunkSampleCounts[chunkIndex];
        long sampleOffset = chunkOffsets[chunkIndex];
  
        while (chunkSamplesRemaining > 0) {
          int bufferSampleCount = Math.min(maxSampleCount, chunkSamplesRemaining);
  
          offsets[newSampleIndex] = sampleOffset;
          sizes[newSampleIndex] = fixedSampleSize * bufferSampleCount;
          maximumSize = Math.max(maximumSize, sizes[newSampleIndex]);
          timestamps[newSampleIndex] = (timestampDeltaInTimeUnits * originalSampleIndex);
          flags[newSampleIndex] = C.BUFFER_FLAG_KEY_FRAME;
  
          sampleOffset += sizes[newSampleIndex];
          originalSampleIndex += bufferSampleCount;
  
          chunkSamplesRemaining -= bufferSampleCount;
          newSampleIndex++;
        }
      }
      long duration = timestampDeltaInTimeUnits * originalSampleIndex;
  
      return new Results(offsets, sizes, maximumSize, timestamps, flags, duration);
    }
  
  }
  