android-34/com/google/android/exoplayer2/extractor/mp4/TrackFragment.java

/*
 * 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 androidx.annotation.Nullable;
import com.google.android.exoplayer2.extractor.ExtractorInput;
import com.google.android.exoplayer2.util.ParsableByteArray;
import java.io.IOException;
import org.checkerframework.checker.nullness.qual.MonotonicNonNull;

/** A holder for information corresponding to a single fragment of an mp4 file. */
/* package */ final class TrackFragment {

  /** The default values for samples from the track fragment header. */
  public @MonotonicNonNull DefaultSampleValues header;
  /** The position (byte offset) of the start of fragment. */
  public long atomPosition;
  /** The position (byte offset) of the start of data contained in the fragment. */
  public long dataPosition;
  /** The position (byte offset) of the start of auxiliary data. */
  public long auxiliaryDataPosition;
  /** The number of track runs of the fragment. */
  public int trunCount;
  /** The total number of samples in the fragment. */
  public int sampleCount;
  /** The position (byte offset) of the start of sample data of each track run in the fragment. */
  public long[] trunDataPosition;
  /** The number of samples contained by each track run in the fragment. */
  public int[] trunLength;
  /** The size of each sample in the fragment. */
  public int[] sampleSizeTable;
  /** The presentation time of each sample in the fragment, in microseconds. */
  public long[] samplePresentationTimesUs;
  /** Indicates which samples are sync frames. */
  public boolean[] sampleIsSyncFrameTable;
  /** Whether the fragment defines encryption data. */
  public boolean definesEncryptionData;
  /**
   * If {@link #definesEncryptionData} is true, indicates which samples use sub-sample encryption.
   * Undefined otherwise.
   */
  public boolean[] sampleHasSubsampleEncryptionTable;
  /** Fragment specific track encryption. May be null. */
  @Nullable public TrackEncryptionBox trackEncryptionBox;
  /**
   * If {@link #definesEncryptionData} is true, contains binary sample encryption data. Undefined
   * otherwise.
   */
  public final ParsableByteArray sampleEncryptionData;
  /** Whether {@link #sampleEncryptionData} needs populating with the actual encryption data. */
  public boolean sampleEncryptionDataNeedsFill;
  /**
   * The duration of all the samples defined in the fragments up to and including this one, plus the
   * duration of the samples defined in the moov atom if {@link #nextFragmentDecodeTimeIncludesMoov}
   * is {@code true}.
   */
  public long nextFragmentDecodeTime;
  /**
   * Whether {@link #nextFragmentDecodeTime} includes the duration of the samples referred to by the
   * moov atom.
   */
  public boolean nextFragmentDecodeTimeIncludesMoov;

  public TrackFragment() {
    trunDataPosition = new long[0];
    trunLength = new int[0];
    sampleSizeTable = new int[0];
    samplePresentationTimesUs = new long[0];
    sampleIsSyncFrameTable = new boolean[0];
    sampleHasSubsampleEncryptionTable = new boolean[0];
    sampleEncryptionData = new ParsableByteArray();
  }

  /**
   * Resets the fragment.
   *
   * <p>{@link #sampleCount} and {@link #nextFragmentDecodeTime} are set to 0, and both {@link
   * #definesEncryptionData} and {@link #sampleEncryptionDataNeedsFill} is set to false, and {@link
   * #trackEncryptionBox} is set to null.
   */
  public void reset() {
    trunCount = 0;
    nextFragmentDecodeTime = 0;
    nextFragmentDecodeTimeIncludesMoov = false;
    definesEncryptionData = false;
    sampleEncryptionDataNeedsFill = false;
    trackEncryptionBox = null;
  }

  /**
   * Configures the fragment for the specified number of samples.
   *
   * <p>The {@link #sampleCount} of the fragment is set to the specified sample count, and the
   * contained tables are resized if necessary such that they are at least this length.
   *
   * @param sampleCount The number of samples in the new run.
   */
  public void initTables(int trunCount, int sampleCount) {
    this.trunCount = trunCount;
    this.sampleCount = sampleCount;
    if (trunLength.length < trunCount) {
      trunDataPosition = new long[trunCount];
      trunLength = new int[trunCount];
    }
    if (sampleSizeTable.length < sampleCount) {
      // Size the tables 25% larger than needed, so as to make future resize operations less
      // likely. The choice of 25% is relatively arbitrary.
      int tableSize = (sampleCount * 125) / 100;
      sampleSizeTable = new int[tableSize];
      samplePresentationTimesUs = new long[tableSize];
      sampleIsSyncFrameTable = new boolean[tableSize];
      sampleHasSubsampleEncryptionTable = new boolean[tableSize];
    }
  }

  /**
   * Configures the fragment to be one that defines encryption data of the specified length.
   *
   * <p>{@link #definesEncryptionData} is set to true, and the {@link ParsableByteArray#limit()
   * limit} of {@link #sampleEncryptionData} is set to the specified length.
   *
   * @param length The length in bytes of the encryption data.
   */
  public void initEncryptionData(int length) {
    sampleEncryptionData.reset(length);
    definesEncryptionData = true;
    sampleEncryptionDataNeedsFill = true;
  }

  /**
   * Fills {@link #sampleEncryptionData} from the provided input.
   *
   * @param input An {@link ExtractorInput} from which to read the encryption data.
   */
  public void fillEncryptionData(ExtractorInput input) throws IOException {
    input.readFully(sampleEncryptionData.getData(), 0, sampleEncryptionData.limit());
    sampleEncryptionData.setPosition(0);
    sampleEncryptionDataNeedsFill = false;
  }

  /**
   * Fills {@link #sampleEncryptionData} from the provided source.
   *
   * @param source A source from which to read the encryption data.
   */
  public void fillEncryptionData(ParsableByteArray source) {
    source.readBytes(sampleEncryptionData.getData(), 0, sampleEncryptionData.limit());
    sampleEncryptionData.setPosition(0);
    sampleEncryptionDataNeedsFill = false;
  }

  /**
   * Returns the sample presentation timestamp in microseconds.
   *
   * @param index The sample index.
   * @return The presentation timestamps of this sample in microseconds.
   */
  public long getSamplePresentationTimeUs(int index) {
    return samplePresentationTimesUs[index];
  }

  /** Returns whether the sample at the given index has a subsample encryption table. */
  public boolean sampleHasSubsampleEncryptionTable(int index) {
    return definesEncryptionData && sampleHasSubsampleEncryptionTable[index];
  }
}