Java Code Examples for com.google.android.exoplayer2.util.ParsableBitArray#skipBits()

/**
 * Returns the DTS format given {@code data} containing the DTS frame according to ETSI TS 102 114
 * subsections 5.3/5.4.
 *
 * @param frame The DTS frame to parse.
 * @param trackId The track identifier to set on the format.
 * @param language The language to set on the format.
 * @param drmInitData {@link DrmInitData} to be included in the format.
 * @return The DTS format parsed from data in the header.
 */
public static Format parseDtsFormat(
    byte[] frame, String trackId, String language, DrmInitData drmInitData) {
  ParsableBitArray frameBits = getNormalizedFrameHeader(frame);
  frameBits.skipBits(32 + 1 + 5 + 1 + 7 + 14); // SYNC, FTYPE, SHORT, CPF, NBLKS, FSIZE
  int amode = frameBits.readBits(6);
  int channelCount = CHANNELS_BY_AMODE[amode];
  int sfreq = frameBits.readBits(4);
  int sampleRate = SAMPLE_RATE_BY_SFREQ[sfreq];
  int rate = frameBits.readBits(5);
  int bitrate = rate >= TWICE_BITRATE_KBPS_BY_RATE.length ? Format.NO_VALUE
      : TWICE_BITRATE_KBPS_BY_RATE[rate] * 1000 / 2;
  frameBits.skipBits(10); // MIX, DYNF, TIMEF, AUXF, HDCD, EXT_AUDIO_ID, EXT_AUDIO, ASPF
  channelCount += frameBits.readBits(2) > 0 ? 1 : 0; // LFF
  return Format.createAudioSampleFormat(trackId, MimeTypes.AUDIO_DTS, null, bitrate,
      Format.NO_VALUE, channelCount, sampleRate, null, drmInitData, 0, language);
}
 

/**
 * Returns the DTS format given {@code data} containing the DTS frame according to ETSI TS 102 114
 * subsections 5.3/5.4.
 *
 * @param frame The DTS frame to parse.
 * @param trackId The track identifier to set on the format.
 * @param language The language to set on the format.
 * @param drmInitData {@link DrmInitData} to be included in the format.
 * @return The DTS format parsed from data in the header.
 */
public static Format parseDtsFormat(
    byte[] frame, String trackId, String language, DrmInitData drmInitData) {
  ParsableBitArray frameBits = getNormalizedFrameHeader(frame);
  frameBits.skipBits(32 + 1 + 5 + 1 + 7 + 14); // SYNC, FTYPE, SHORT, CPF, NBLKS, FSIZE
  int amode = frameBits.readBits(6);
  int channelCount = CHANNELS_BY_AMODE[amode];
  int sfreq = frameBits.readBits(4);
  int sampleRate = SAMPLE_RATE_BY_SFREQ[sfreq];
  int rate = frameBits.readBits(5);
  int bitrate = rate >= TWICE_BITRATE_KBPS_BY_RATE.length ? Format.NO_VALUE
      : TWICE_BITRATE_KBPS_BY_RATE[rate] * 1000 / 2;
  frameBits.skipBits(10); // MIX, DYNF, TIMEF, AUXF, HDCD, EXT_AUDIO_ID, EXT_AUDIO, ASPF
  channelCount += frameBits.readBits(2) > 0 ? 1 : 0; // LFF
  return Format.createAudioSampleFormat(trackId, MimeTypes.AUDIO_DTS, null, bitrate,
      Format.NO_VALUE, channelCount, sampleRate, null, drmInitData, 0, language);
}
 

/**
 * Parses an AudioMuxElement as defined in 14496-3:2009, Section 1.7.3.1, Table 1.41.
 *
 * @param data A {@link ParsableBitArray} containing the AudioMuxElement's bytes.
 */
private void parseAudioMuxElement(ParsableBitArray data) throws ParserException {
  boolean useSameStreamMux = data.readBit();
  if (!useSameStreamMux) {
    streamMuxRead = true;
    parseStreamMuxConfig(data);
  } else if (!streamMuxRead) {
    return; // Parsing cannot continue without StreamMuxConfig information.
  }

  if (audioMuxVersionA == 0) {
    if (numSubframes != 0) {
      throw new ParserException();
    }
    int muxSlotLengthBytes = parsePayloadLengthInfo(data);
    parsePayloadMux(data, muxSlotLengthBytes);
    if (otherDataPresent) {
      data.skipBits((int) otherDataLenBits);
    }
  } else {
    throw new ParserException(); // Not defined by ISO/IEC 14496-3:2009.
  }
}
 

/**
 * Returns the DTS format given {@code data} containing the DTS frame according to ETSI TS 102 114
 * subsections 5.3/5.4.
 *
 * @param frame The DTS frame to parse.
 * @param trackId The track identifier to set on the format.
 * @param language The language to set on the format.
 * @param drmInitData {@link DrmInitData} to be included in the format.
 * @return The DTS format parsed from data in the header.
 */
public static Format parseDtsFormat(
    byte[] frame, String trackId, String language, DrmInitData drmInitData) {
  ParsableBitArray frameBits = getNormalizedFrameHeader(frame);
  frameBits.skipBits(32 + 1 + 5 + 1 + 7 + 14); // SYNC, FTYPE, SHORT, CPF, NBLKS, FSIZE
  int amode = frameBits.readBits(6);
  int channelCount = CHANNELS_BY_AMODE[amode];
  int sfreq = frameBits.readBits(4);
  int sampleRate = SAMPLE_RATE_BY_SFREQ[sfreq];
  int rate = frameBits.readBits(5);
  int bitrate = rate >= TWICE_BITRATE_KBPS_BY_RATE.length ? Format.NO_VALUE
      : TWICE_BITRATE_KBPS_BY_RATE[rate] * 1000 / 2;
  frameBits.skipBits(10); // MIX, DYNF, TIMEF, AUXF, HDCD, EXT_AUDIO_ID, EXT_AUDIO, ASPF
  channelCount += frameBits.readBits(2) > 0 ? 1 : 0; // LFF
  return Format.createAudioSampleFormat(trackId, MimeTypes.AUDIO_DTS, null, bitrate,
      Format.NO_VALUE, channelCount, sampleRate, null, drmInitData, 0, language);
}
 

/**
 * Parses a page composition segment, as defined by ETSI EN 300 743 7.2.2.
 */
private static PageComposition parsePageComposition(ParsableBitArray data, int length) {
  int timeoutSecs = data.readBits(8);
  int version = data.readBits(4);
  int state = data.readBits(2);
  data.skipBits(2);
  int remainingLength = length - 2;

  SparseArray<PageRegion> regions = new SparseArray<>();
  while (remainingLength > 0) {
    int regionId = data.readBits(8);
    data.skipBits(8); // Skip reserved.
    int regionHorizontalAddress = data.readBits(16);
    int regionVerticalAddress = data.readBits(16);
    remainingLength -= 6;
    regions.put(regionId, new PageRegion(regionHorizontalAddress, regionVerticalAddress));
  }

  return new PageComposition(timeoutSecs, version, state, regions);
}
 

/**
 * Parses an AudioMuxElement as defined in 14496-3:2009, Section 1.7.3.1, Table 1.41.
 *
 * @param data A {@link ParsableBitArray} containing the AudioMuxElement's bytes.
 */
private void parseAudioMuxElement(ParsableBitArray data) throws ParserException {
  boolean useSameStreamMux = data.readBit();
  if (!useSameStreamMux) {
    streamMuxRead = true;
    parseStreamMuxConfig(data);
  } else if (!streamMuxRead) {
    return; // Parsing cannot continue without StreamMuxConfig information.
  }

  if (audioMuxVersionA == 0) {
    if (numSubframes != 0) {
      throw new ParserException();
    }
    int muxSlotLengthBytes = parsePayloadLengthInfo(data);
    parsePayloadMux(data, muxSlotLengthBytes);
    if (otherDataPresent) {
      data.skipBits((int) otherDataLenBits);
    }
  } else {
    throw new ParserException(); // Not defined by ISO/IEC 14496-3:2009.
  }
}
 

private void parseFrameLength(ParsableBitArray data) {
  frameLengthType = data.readBits(3);
  switch (frameLengthType) {
    case 0:
      data.skipBits(8); // latmBufferFullness.
      break;
    case 1:
      data.skipBits(9); // frameLength.
      break;
    case 3:
    case 4:
    case 5:
      data.skipBits(6); // CELPframeLengthTableIndex.
      break;
    case 6:
    case 7:
      data.skipBits(1); // HVXCframeLengthTableIndex.
      break;
  }
}
 

/**
 * Parses a page composition segment, as defined by ETSI EN 300 743 7.2.2.
 */
private static PageComposition parsePageComposition(ParsableBitArray data, int length) {
  int timeoutSecs = data.readBits(8);
  int version = data.readBits(4);
  int state = data.readBits(2);
  data.skipBits(2);
  int remainingLength = length - 2;

  SparseArray<PageRegion> regions = new SparseArray<>();
  while (remainingLength > 0) {
    int regionId = data.readBits(8);
    data.skipBits(8); // Skip reserved.
    int regionHorizontalAddress = data.readBits(16);
    int regionVerticalAddress = data.readBits(16);
    remainingLength -= 6;
    regions.put(regionId, new PageRegion(regionHorizontalAddress, regionVerticalAddress));
  }

  return new PageComposition(timeoutSecs, version, state, regions);
}
 

/**
 * Returns the DTS format given {@code data} containing the DTS frame according to ETSI TS 102 114
 * subsections 5.3/5.4.
 *
 * @param frame The DTS frame to parse.
 * @param trackId The track identifier to set on the format.
 * @param language The language to set on the format.
 * @param drmInitData {@link DrmInitData} to be included in the format.
 * @return The DTS format parsed from data in the header.
 */
public static Format parseDtsFormat(
    byte[] frame, String trackId, String language, DrmInitData drmInitData) {
  ParsableBitArray frameBits = getNormalizedFrameHeader(frame);
  frameBits.skipBits(32 + 1 + 5 + 1 + 7 + 14); // SYNC, FTYPE, SHORT, CPF, NBLKS, FSIZE
  int amode = frameBits.readBits(6);
  int channelCount = CHANNELS_BY_AMODE[amode];
  int sfreq = frameBits.readBits(4);
  int sampleRate = SAMPLE_RATE_BY_SFREQ[sfreq];
  int rate = frameBits.readBits(5);
  int bitrate = rate >= TWICE_BITRATE_KBPS_BY_RATE.length ? Format.NO_VALUE
      : TWICE_BITRATE_KBPS_BY_RATE[rate] * 1000 / 2;
  frameBits.skipBits(10); // MIX, DYNF, TIMEF, AUXF, HDCD, EXT_AUDIO_ID, EXT_AUDIO, ASPF
  channelCount += frameBits.readBits(2) > 0 ? 1 : 0; // LFF
  return Format.createAudioSampleFormat(trackId, MimeTypes.AUDIO_DTS, null, bitrate,
      Format.NO_VALUE, channelCount, sampleRate, null, drmInitData, 0, language);
}
 

private static ParsableBitArray getNormalizedFrameHeader(byte[] frameHeader) {
  if (frameHeader[0] == FIRST_BYTE_BE) {
    // The frame is already 16-bit mode, big endian.
    return new ParsableBitArray(frameHeader);
  }
  // Data is not normalized, but we don't want to modify frameHeader.
  frameHeader = Arrays.copyOf(frameHeader, frameHeader.length);
  if (isLittleEndianFrameHeader(frameHeader)) {
    // Change endianness.
    for (int i = 0; i < frameHeader.length - 1; i += 2) {
      byte temp = frameHeader[i];
      frameHeader[i] = frameHeader[i + 1];
      frameHeader[i + 1] = temp;
    }
  }
  ParsableBitArray frameBits = new ParsableBitArray(frameHeader);
  if (frameHeader[0] == (byte) (SYNC_VALUE_14B_BE >> 24)) {
    // Discard the 2 most significant bits of each 16 bit word.
    ParsableBitArray scratchBits = new ParsableBitArray(frameHeader);
    while (scratchBits.bitsLeft() >= 16) {
      scratchBits.skipBits(2);
      frameBits.putInt(scratchBits.readBits(14), 14);
    }
  }
  frameBits.reset(frameHeader);
  return frameBits;
}
 

/**
 * Parses a display definition segment, as defined by ETSI EN 300 743 7.2.1.
 */
private static DisplayDefinition parseDisplayDefinition(ParsableBitArray data) {
  data.skipBits(4); // dds_version_number (4).
  boolean displayWindowFlag = data.readBit();
  data.skipBits(3); // Skip reserved.
  int width = data.readBits(16);
  int height = data.readBits(16);

  int horizontalPositionMinimum;
  int horizontalPositionMaximum;
  int verticalPositionMinimum;
  int verticalPositionMaximum;
  if (displayWindowFlag) {
    horizontalPositionMinimum = data.readBits(16);
    horizontalPositionMaximum = data.readBits(16);
    verticalPositionMinimum = data.readBits(16);
    verticalPositionMaximum = data.readBits(16);
  } else {
    horizontalPositionMinimum = 0;
    horizontalPositionMaximum = width;
    verticalPositionMinimum = 0;
    verticalPositionMaximum = height;
  }

  return new DisplayDefinition(width, height, horizontalPositionMinimum,
      horizontalPositionMaximum, verticalPositionMinimum, verticalPositionMaximum);
}
 

/**
 * Parses an object data segment, as defined by ETSI EN 300 743 7.2.5.
 *
 * @return The parsed object data.
 */
private static ObjectData parseObjectData(ParsableBitArray data) {
  int objectId = data.readBits(16);
  data.skipBits(4); // Skip object_version_number
  int objectCodingMethod = data.readBits(2);
  boolean nonModifyingColorFlag = data.readBit();
  data.skipBits(1); // Skip reserved.

  @Nullable byte[] topFieldData = null;
  @Nullable byte[] bottomFieldData = null;

  if (objectCodingMethod == OBJECT_CODING_STRING) {
    int numberOfCodes = data.readBits(8);
    // TODO: Parse and use character_codes.
    data.skipBits(numberOfCodes * 16); // Skip character_codes.
  } else if (objectCodingMethod == OBJECT_CODING_PIXELS) {
    int topFieldDataLength = data.readBits(16);
    int bottomFieldDataLength = data.readBits(16);
    if (topFieldDataLength > 0) {
      topFieldData = new byte[topFieldDataLength];
      data.readBytes(topFieldData, 0, topFieldDataLength);
    }
    if (bottomFieldDataLength > 0) {
      bottomFieldData = new byte[bottomFieldDataLength];
      data.readBytes(bottomFieldData, 0, bottomFieldDataLength);
    } else {
      bottomFieldData = topFieldData;
    }
  }

  return new ObjectData(objectId, nonModifyingColorFlag, topFieldData, bottomFieldData);
}
 

private static ParsableBitArray getNormalizedFrameHeader(byte[] frameHeader) {
  if (frameHeader[0] == FIRST_BYTE_BE) {
    // The frame is already 16-bit mode, big endian.
    return new ParsableBitArray(frameHeader);
  }
  // Data is not normalized, but we don't want to modify frameHeader.
  frameHeader = Arrays.copyOf(frameHeader, frameHeader.length);
  if (isLittleEndianFrameHeader(frameHeader)) {
    // Change endianness.
    for (int i = 0; i < frameHeader.length - 1; i += 2) {
      byte temp = frameHeader[i];
      frameHeader[i] = frameHeader[i + 1];
      frameHeader[i + 1] = temp;
    }
  }
  ParsableBitArray frameBits = new ParsableBitArray(frameHeader);
  if (frameHeader[0] == (byte) (SYNC_VALUE_14B_BE >> 24)) {
    // Discard the 2 most significant bits of each 16 bit word.
    ParsableBitArray scratchBits = new ParsableBitArray(frameHeader);
    while (scratchBits.bitsLeft() >= 16) {
      scratchBits.skipBits(2);
      frameBits.putInt(scratchBits.readBits(14), 14);
    }
  }
  frameBits.reset(frameHeader);
  return frameBits;
}
 

/**
 * Parses a display definition segment, as defined by ETSI EN 300 743 7.2.1.
 */
private static DisplayDefinition parseDisplayDefinition(ParsableBitArray data) {
  data.skipBits(4); // dds_version_number (4).
  boolean displayWindowFlag = data.readBit();
  data.skipBits(3); // Skip reserved.
  int width = data.readBits(16);
  int height = data.readBits(16);

  int horizontalPositionMinimum;
  int horizontalPositionMaximum;
  int verticalPositionMinimum;
  int verticalPositionMaximum;
  if (displayWindowFlag) {
    horizontalPositionMinimum = data.readBits(16);
    horizontalPositionMaximum = data.readBits(16);
    verticalPositionMinimum = data.readBits(16);
    verticalPositionMaximum = data.readBits(16);
  } else {
    horizontalPositionMinimum = 0;
    horizontalPositionMaximum = width;
    verticalPositionMinimum = 0;
    verticalPositionMaximum = height;
  }

  return new DisplayDefinition(width, height, horizontalPositionMinimum,
      horizontalPositionMaximum, verticalPositionMinimum, verticalPositionMaximum);
}
 

/**
 * Parses an object data segment, as defined by ETSI EN 300 743 7.2.5.
 *
 * @return The parsed object data.
 */
private static ObjectData parseObjectData(ParsableBitArray data) {
  int objectId = data.readBits(16);
  data.skipBits(4); // Skip object_version_number
  int objectCodingMethod = data.readBits(2);
  boolean nonModifyingColorFlag = data.readBit();
  data.skipBits(1); // Skip reserved.

  byte[] topFieldData = null;
  byte[] bottomFieldData = null;

  if (objectCodingMethod == OBJECT_CODING_STRING) {
    int numberOfCodes = data.readBits(8);
    // TODO: Parse and use character_codes.
    data.skipBits(numberOfCodes * 16); // Skip character_codes.
  } else if (objectCodingMethod == OBJECT_CODING_PIXELS) {
    int topFieldDataLength = data.readBits(16);
    int bottomFieldDataLength = data.readBits(16);
    if (topFieldDataLength > 0) {
      topFieldData = new byte[topFieldDataLength];
      data.readBytes(topFieldData, 0, topFieldDataLength);
    }
    if (bottomFieldDataLength > 0) {
      bottomFieldData = new byte[bottomFieldDataLength];
      data.readBytes(bottomFieldData, 0, bottomFieldDataLength);
    } else {
      bottomFieldData = topFieldData;
    }
  }

  return new ObjectData(objectId, nonModifyingColorFlag, topFieldData, bottomFieldData);
}
 

/**
 * Parses a display definition segment, as defined by ETSI EN 300 743 7.2.1.
 */
private static DisplayDefinition parseDisplayDefinition(ParsableBitArray data) {
  data.skipBits(4); // dds_version_number (4).
  boolean displayWindowFlag = data.readBit();
  data.skipBits(3); // Skip reserved.
  int width = data.readBits(16);
  int height = data.readBits(16);

  int horizontalPositionMinimum;
  int horizontalPositionMaximum;
  int verticalPositionMinimum;
  int verticalPositionMaximum;
  if (displayWindowFlag) {
    horizontalPositionMinimum = data.readBits(16);
    horizontalPositionMaximum = data.readBits(16);
    verticalPositionMinimum = data.readBits(16);
    verticalPositionMaximum = data.readBits(16);
  } else {
    horizontalPositionMinimum = 0;
    horizontalPositionMaximum = width;
    verticalPositionMinimum = 0;
    verticalPositionMaximum = height;
  }

  return new DisplayDefinition(width, height, horizontalPositionMinimum,
      horizontalPositionMaximum, verticalPositionMinimum, verticalPositionMaximum);
}
 

/**
 * Parses a CLUT definition segment, as defined by ETSI EN 300 743 7.2.4.
 */
private static ClutDefinition parseClutDefinition(ParsableBitArray data, int length) {
  int clutId = data.readBits(8);
  data.skipBits(8); // Skip clut_version_number (4), reserved (4)
  int remainingLength = length - 2;

  int[] clutEntries2Bit = generateDefault2BitClutEntries();
  int[] clutEntries4Bit = generateDefault4BitClutEntries();
  int[] clutEntries8Bit = generateDefault8BitClutEntries();

  while (remainingLength > 0) {
    int entryId = data.readBits(8);
    int entryFlags = data.readBits(8);
    remainingLength -= 2;

    int[] clutEntries;
    if ((entryFlags & 0x80) != 0) {
      clutEntries = clutEntries2Bit;
    } else if ((entryFlags & 0x40) != 0) {
      clutEntries = clutEntries4Bit;
    } else {
      clutEntries = clutEntries8Bit;
    }

    int y;
    int cr;
    int cb;
    int t;
    if ((entryFlags & 0x01) != 0) {
      y = data.readBits(8);
      cr = data.readBits(8);
      cb = data.readBits(8);
      t = data.readBits(8);
      remainingLength -= 4;
    } else {
      y = data.readBits(6) << 2;
      cr = data.readBits(4) << 4;
      cb = data.readBits(4) << 4;
      t = data.readBits(2) << 6;
      remainingLength -= 2;
    }

    if (y == 0x00) {
      cr = 0x00;
      cb = 0x00;
      t = 0xFF;
    }

    int a = (byte) (0xFF - (t & 0xFF));
    int r = (int) (y + (1.40200 * (cr - 128)));
    int g = (int) (y - (0.34414 * (cb - 128)) - (0.71414 * (cr - 128)));
    int b = (int) (y + (1.77200 * (cb - 128)));
    clutEntries[entryId] = getColor(a, Util.constrainValue(r, 0, 255),
        Util.constrainValue(g, 0, 255), Util.constrainValue(b, 0, 255));
  }

  return new ClutDefinition(clutId, clutEntries2Bit, clutEntries4Bit, clutEntries8Bit);
}
 

/**
 * Returns AC-4 format information given {@code data} containing a syncframe. The reading position
 * of {@code data} will be modified.
 *
 * @param data The data to parse, positioned at the start of the syncframe.
 * @return The AC-4 format data parsed from the header.
 */
public static SyncFrameInfo parseAc4SyncframeInfo(ParsableBitArray data) {
  int headerSize = 0;
  int syncWord = data.readBits(16);
  headerSize += 2;
  int frameSize = data.readBits(16);
  headerSize += 2;
  if (frameSize == 0xFFFF) {
    frameSize = data.readBits(24);
    headerSize += 3; // Extended frame_size
  }
  frameSize += headerSize;
  if (syncWord == AC41_SYNCWORD) {
    frameSize += 2; // crc_word
  }
  int bitstreamVersion = data.readBits(2);
  if (bitstreamVersion == 3) {
    bitstreamVersion += readVariableBits(data, /* bitsPerRead= */ 2);
  }
  int sequenceCounter = data.readBits(10);
  if (data.readBit()) { // b_wait_frames
    if (data.readBits(3) > 0) { // wait_frames
      data.skipBits(2); // reserved
    }
  }
  int sampleRate = data.readBit() ? 48000 : 44100;
  int frameRateIndex = data.readBits(4);
  int sampleCount = 0;
  if (sampleRate == 44100 && frameRateIndex == 13) {
    sampleCount = SAMPLE_COUNT[frameRateIndex];
  } else if (sampleRate == 48000 && frameRateIndex < SAMPLE_COUNT.length) {
    sampleCount = SAMPLE_COUNT[frameRateIndex];
    switch (sequenceCounter % 5) {
      case 1: // fall through
      case 3:
        if (frameRateIndex == 3 || frameRateIndex == 8) {
          sampleCount++;
        }
        break;
      case 2:
        if (frameRateIndex == 8 || frameRateIndex == 11) {
          sampleCount++;
        }
        break;
      case 4:
        if (frameRateIndex == 3 || frameRateIndex == 8 || frameRateIndex == 11) {
          sampleCount++;
        }
        break;
      default:
        break;
    }
  }
  return new SyncFrameInfo(bitstreamVersion, CHANNEL_COUNT_2, sampleRate, frameSize, sampleCount);
}
 

/**
 * Parses a CLUT definition segment, as defined by ETSI EN 300 743 7.2.4.
 */
private static ClutDefinition parseClutDefinition(ParsableBitArray data, int length) {
  int clutId = data.readBits(8);
  data.skipBits(8); // Skip clut_version_number (4), reserved (4)
  int remainingLength = length - 2;

  int[] clutEntries2Bit = generateDefault2BitClutEntries();
  int[] clutEntries4Bit = generateDefault4BitClutEntries();
  int[] clutEntries8Bit = generateDefault8BitClutEntries();

  while (remainingLength > 0) {
    int entryId = data.readBits(8);
    int entryFlags = data.readBits(8);
    remainingLength -= 2;

    int[] clutEntries;
    if ((entryFlags & 0x80) != 0) {
      clutEntries = clutEntries2Bit;
    } else if ((entryFlags & 0x40) != 0) {
      clutEntries = clutEntries4Bit;
    } else {
      clutEntries = clutEntries8Bit;
    }

    int y;
    int cr;
    int cb;
    int t;
    if ((entryFlags & 0x01) != 0) {
      y = data.readBits(8);
      cr = data.readBits(8);
      cb = data.readBits(8);
      t = data.readBits(8);
      remainingLength -= 4;
    } else {
      y = data.readBits(6) << 2;
      cr = data.readBits(4) << 4;
      cb = data.readBits(4) << 4;
      t = data.readBits(2) << 6;
      remainingLength -= 2;
    }

    if (y == 0x00) {
      cr = 0x00;
      cb = 0x00;
      t = 0xFF;
    }

    int a = (byte) (0xFF - (t & 0xFF));
    int r = (int) (y + (1.40200 * (cr - 128)));
    int g = (int) (y - (0.34414 * (cb - 128)) - (0.71414 * (cr - 128)));
    int b = (int) (y + (1.77200 * (cb - 128)));
    clutEntries[entryId] = getColor(a, Util.constrainValue(r, 0, 255),
        Util.constrainValue(g, 0, 255), Util.constrainValue(b, 0, 255));
  }

  return new ClutDefinition(clutId, clutEntries2Bit, clutEntries4Bit, clutEntries8Bit);
}
 

/**
 * Returns AC-4 format information given {@code data} containing a syncframe. The reading position
 * of {@code data} will be modified.
 *
 * @param data The data to parse, positioned at the start of the syncframe.
 * @return The AC-4 format data parsed from the header.
 */
public static SyncFrameInfo parseAc4SyncframeInfo(ParsableBitArray data) {
  int headerSize = 0;
  int syncWord = data.readBits(16);
  headerSize += 2;
  int frameSize = data.readBits(16);
  headerSize += 2;
  if (frameSize == 0xFFFF) {
    frameSize = data.readBits(24);
    headerSize += 3; // Extended frame_size
  }
  frameSize += headerSize;
  if (syncWord == AC41_SYNCWORD) {
    frameSize += 2; // crc_word
  }
  int bitstreamVersion = data.readBits(2);
  if (bitstreamVersion == 3) {
    bitstreamVersion += readVariableBits(data, /* bitsPerRead= */ 2);
  }
  int sequenceCounter = data.readBits(10);
  if (data.readBit()) { // b_wait_frames
    if (data.readBits(3) > 0) { // wait_frames
      data.skipBits(2); // reserved
    }
  }
  int sampleRate = data.readBit() ? 48000 : 44100;
  int frameRateIndex = data.readBits(4);
  int sampleCount = 0;
  if (sampleRate == 44100 && frameRateIndex == 13) {
    sampleCount = SAMPLE_COUNT[frameRateIndex];
  } else if (sampleRate == 48000 && frameRateIndex < SAMPLE_COUNT.length) {
    sampleCount = SAMPLE_COUNT[frameRateIndex];
    switch (sequenceCounter % 5) {
      case 1: // fall through
      case 3:
        if (frameRateIndex == 3 || frameRateIndex == 8) {
          sampleCount++;
        }
        break;
      case 2:
        if (frameRateIndex == 8 || frameRateIndex == 11) {
          sampleCount++;
        }
        break;
      case 4:
        if (frameRateIndex == 3 || frameRateIndex == 8 || frameRateIndex == 11) {
          sampleCount++;
        }
        break;
      default:
        break;
    }
  }
  return new SyncFrameInfo(bitstreamVersion, CHANNEL_COUNT_2, sampleRate, frameSize, sampleCount);
}