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.mkv;
  
  import static com.google.android.exoplayer2.util.Assertions.checkArgument;
  import static com.google.android.exoplayer2.util.Assertions.checkNotNull;
  import static com.google.android.exoplayer2.util.Assertions.checkState;
  import static com.google.android.exoplayer2.util.Assertions.checkStateNotNull;
  import static java.lang.Math.max;
  import static java.lang.Math.min;
  import static java.lang.annotation.ElementType.TYPE_USE;
  
  import android.util.Pair;
  import android.util.SparseArray;
  import androidx.annotation.CallSuper;
  import androidx.annotation.IntDef;
  import androidx.annotation.Nullable;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.Format;
  import com.google.android.exoplayer2.ParserException;
  import com.google.android.exoplayer2.audio.AacUtil;
  import com.google.android.exoplayer2.audio.MpegAudioUtil;
  import com.google.android.exoplayer2.drm.DrmInitData;
  import com.google.android.exoplayer2.drm.DrmInitData.SchemeData;
  import com.google.android.exoplayer2.extractor.ChunkIndex;
  import com.google.android.exoplayer2.extractor.Extractor;
  import com.google.android.exoplayer2.extractor.ExtractorInput;
  import com.google.android.exoplayer2.extractor.ExtractorOutput;
  import com.google.android.exoplayer2.extractor.ExtractorsFactory;
  import com.google.android.exoplayer2.extractor.PositionHolder;
  import com.google.android.exoplayer2.extractor.SeekMap;
  import com.google.android.exoplayer2.extractor.TrackOutput;
  import com.google.android.exoplayer2.extractor.TrueHdSampleRechunker;
  import com.google.android.exoplayer2.util.Log;
  import com.google.android.exoplayer2.util.LongArray;
  import com.google.android.exoplayer2.util.MimeTypes;
  import com.google.android.exoplayer2.util.NalUnitUtil;
  import com.google.android.exoplayer2.util.ParsableByteArray;
  import com.google.android.exoplayer2.util.Util;
  import com.google.android.exoplayer2.video.AvcConfig;
  import com.google.android.exoplayer2.video.ColorInfo;
  import com.google.android.exoplayer2.video.DolbyVisionConfig;
  import com.google.android.exoplayer2.video.HevcConfig;
  import com.google.common.collect.ImmutableList;
  import java.io.IOException;
  import java.lang.annotation.Documented;
  import java.lang.annotation.Retention;
  import java.lang.annotation.RetentionPolicy;
  import java.lang.annotation.Target;
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.UUID;
  import org.checkerframework.checker.nullness.compatqual.NullableType;
  import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
  import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
  import org.checkerframework.checker.nullness.qual.RequiresNonNull;
  
  /** Extracts data from the Matroska and WebM container formats. */
  public class MatroskaExtractor implements Extractor {
  
    /** Factory for {@link MatroskaExtractor} instances. */
    public static final ExtractorsFactory FACTORY = () -> new Extractor[] {new MatroskaExtractor()};
  
    /**
     * Flags controlling the behavior of the extractor. Possible flag value is {@link
     * #FLAG_DISABLE_SEEK_FOR_CUES}.
     */
    @Documented
    @Retention(RetentionPolicy.SOURCE)
    @Target(TYPE_USE)
    @IntDef(
        flag = true,
        value = {FLAG_DISABLE_SEEK_FOR_CUES})
    public @interface Flags {}
    /**
     * Flag to disable seeking for cues.
     *
     * <p>Normally (i.e. when this flag is not set) the extractor will seek to the cues element if its
     * position is specified in the seek head and if it's after the first cluster. Setting this flag
     * disables seeking to the cues element. If the cues element is after the first cluster then the
     * media is treated as being unseekable.
     */
    public static final int FLAG_DISABLE_SEEK_FOR_CUES = 1;
  
    private static final String TAG = "MatroskaExtractor";
  
    private static final int UNSET_ENTRY_ID = -1;
  
    private static final int BLOCK_STATE_START = 0;
    private static final int BLOCK_STATE_HEADER = 1;
    private static final int BLOCK_STATE_DATA = 2;
  
    private static final String DOC_TYPE_MATROSKA = "matroska";
    private static final String DOC_TYPE_WEBM = "webm";
    private static final String CODEC_ID_VP8 = "V_VP8";
    private static final String CODEC_ID_VP9 = "V_VP9";
    private static final String CODEC_ID_AV1 = "V_AV1";
    private static final String CODEC_ID_MPEG2 = "V_MPEG2";
    private static final String CODEC_ID_MPEG4_SP = "V_MPEG4/ISO/SP";
    private static final String CODEC_ID_MPEG4_ASP = "V_MPEG4/ISO/ASP";
    private static final String CODEC_ID_MPEG4_AP = "V_MPEG4/ISO/AP";
    private static final String CODEC_ID_H264 = "V_MPEG4/ISO/AVC";
    private static final String CODEC_ID_H265 = "V_MPEGH/ISO/HEVC";
    private static final String CODEC_ID_FOURCC = "V_MS/VFW/FOURCC";
    private static final String CODEC_ID_THEORA = "V_THEORA";
    private static final String CODEC_ID_VORBIS = "A_VORBIS";
    private static final String CODEC_ID_OPUS = "A_OPUS";
    private static final String CODEC_ID_AAC = "A_AAC";
    private static final String CODEC_ID_MP2 = "A_MPEG/L2";
    private static final String CODEC_ID_MP3 = "A_MPEG/L3";
    private static final String CODEC_ID_AC3 = "A_AC3";
    private static final String CODEC_ID_E_AC3 = "A_EAC3";
    private static final String CODEC_ID_TRUEHD = "A_TRUEHD";
    private static final String CODEC_ID_DTS = "A_DTS";
    private static final String CODEC_ID_DTS_EXPRESS = "A_DTS/EXPRESS";
    private static final String CODEC_ID_DTS_LOSSLESS = "A_DTS/LOSSLESS";
    private static final String CODEC_ID_FLAC = "A_FLAC";
    private static final String CODEC_ID_ACM = "A_MS/ACM";
    private static final String CODEC_ID_PCM_INT_LIT = "A_PCM/INT/LIT";
    private static final String CODEC_ID_PCM_INT_BIG = "A_PCM/INT/BIG";
    private static final String CODEC_ID_PCM_FLOAT = "A_PCM/FLOAT/IEEE";
    private static final String CODEC_ID_SUBRIP = "S_TEXT/UTF8";
    private static final String CODEC_ID_ASS = "S_TEXT/ASS";
    private static final String CODEC_ID_VTT = "S_TEXT/WEBVTT";
    private static final String CODEC_ID_VOBSUB = "S_VOBSUB";
    private static final String CODEC_ID_PGS = "S_HDMV/PGS";
    private static final String CODEC_ID_DVBSUB = "S_DVBSUB";
  
    private static final int VORBIS_MAX_INPUT_SIZE = 8192;
    private static final int OPUS_MAX_INPUT_SIZE = 5760;
    private static final int ENCRYPTION_IV_SIZE = 8;
    private static final int TRACK_TYPE_AUDIO = 2;
  
    private static final int ID_EBML = 0x1A45DFA3;
    private static final int ID_EBML_READ_VERSION = 0x42F7;
    private static final int ID_DOC_TYPE = 0x4282;
    private static final int ID_DOC_TYPE_READ_VERSION = 0x4285;
    private static final int ID_SEGMENT = 0x18538067;
    private static final int ID_SEGMENT_INFO = 0x1549A966;
    private static final int ID_SEEK_HEAD = 0x114D9B74;
    private static final int ID_SEEK = 0x4DBB;
    private static final int ID_SEEK_ID = 0x53AB;
    private static final int ID_SEEK_POSITION = 0x53AC;
    private static final int ID_INFO = 0x1549A966;
    private static final int ID_TIMECODE_SCALE = 0x2AD7B1;
    private static final int ID_DURATION = 0x4489;
    private static final int ID_CLUSTER = 0x1F43B675;
    private static final int ID_TIME_CODE = 0xE7;
    private static final int ID_SIMPLE_BLOCK = 0xA3;
    private static final int ID_BLOCK_GROUP = 0xA0;
    private static final int ID_BLOCK = 0xA1;
    private static final int ID_BLOCK_DURATION = 0x9B;
    private static final int ID_BLOCK_ADDITIONS = 0x75A1;
    private static final int ID_BLOCK_MORE = 0xA6;
    private static final int ID_BLOCK_ADD_ID = 0xEE;
    private static final int ID_BLOCK_ADDITIONAL = 0xA5;
    private static final int ID_REFERENCE_BLOCK = 0xFB;
    private static final int ID_TRACKS = 0x1654AE6B;
    private static final int ID_TRACK_ENTRY = 0xAE;
    private static final int ID_TRACK_NUMBER = 0xD7;
    private static final int ID_TRACK_TYPE = 0x83;
    private static final int ID_FLAG_DEFAULT = 0x88;
    private static final int ID_FLAG_FORCED = 0x55AA;
    private static final int ID_DEFAULT_DURATION = 0x23E383;
    private static final int ID_MAX_BLOCK_ADDITION_ID = 0x55EE;
    private static final int ID_BLOCK_ADDITION_MAPPING = 0x41E4;
    private static final int ID_BLOCK_ADD_ID_TYPE = 0x41E7;
    private static final int ID_BLOCK_ADD_ID_EXTRA_DATA = 0x41ED;
    private static final int ID_NAME = 0x536E;
    private static final int ID_CODEC_ID = 0x86;
    private static final int ID_CODEC_PRIVATE = 0x63A2;
    private static final int ID_CODEC_DELAY = 0x56AA;
    private static final int ID_SEEK_PRE_ROLL = 0x56BB;
    private static final int ID_DISCARD_PADDING = 0x75A2;
    private static final int ID_VIDEO = 0xE0;
    private static final int ID_PIXEL_WIDTH = 0xB0;
    private static final int ID_PIXEL_HEIGHT = 0xBA;
    private static final int ID_DISPLAY_WIDTH = 0x54B0;
    private static final int ID_DISPLAY_HEIGHT = 0x54BA;
    private static final int ID_DISPLAY_UNIT = 0x54B2;
    private static final int ID_AUDIO = 0xE1;
    private static final int ID_CHANNELS = 0x9F;
    private static final int ID_AUDIO_BIT_DEPTH = 0x6264;
    private static final int ID_SAMPLING_FREQUENCY = 0xB5;
    private static final int ID_CONTENT_ENCODINGS = 0x6D80;
    private static final int ID_CONTENT_ENCODING = 0x6240;
    private static final int ID_CONTENT_ENCODING_ORDER = 0x5031;
    private static final int ID_CONTENT_ENCODING_SCOPE = 0x5032;
    private static final int ID_CONTENT_COMPRESSION = 0x5034;
    private static final int ID_CONTENT_COMPRESSION_ALGORITHM = 0x4254;
    private static final int ID_CONTENT_COMPRESSION_SETTINGS = 0x4255;
    private static final int ID_CONTENT_ENCRYPTION = 0x5035;
    private static final int ID_CONTENT_ENCRYPTION_ALGORITHM = 0x47E1;
    private static final int ID_CONTENT_ENCRYPTION_KEY_ID = 0x47E2;
    private static final int ID_CONTENT_ENCRYPTION_AES_SETTINGS = 0x47E7;
    private static final int ID_CONTENT_ENCRYPTION_AES_SETTINGS_CIPHER_MODE = 0x47E8;
    private static final int ID_CUES = 0x1C53BB6B;
    private static final int ID_CUE_POINT = 0xBB;
    private static final int ID_CUE_TIME = 0xB3;
    private static final int ID_CUE_TRACK_POSITIONS = 0xB7;
    private static final int ID_CUE_CLUSTER_POSITION = 0xF1;
    private static final int ID_LANGUAGE = 0x22B59C;
    private static final int ID_PROJECTION = 0x7670;
    private static final int ID_PROJECTION_TYPE = 0x7671;
    private static final int ID_PROJECTION_PRIVATE = 0x7672;
    private static final int ID_PROJECTION_POSE_YAW = 0x7673;
    private static final int ID_PROJECTION_POSE_PITCH = 0x7674;
    private static final int ID_PROJECTION_POSE_ROLL = 0x7675;
    private static final int ID_STEREO_MODE = 0x53B8;
    private static final int ID_COLOUR = 0x55B0;
    private static final int ID_COLOUR_RANGE = 0x55B9;
    private static final int ID_COLOUR_TRANSFER = 0x55BA;
    private static final int ID_COLOUR_PRIMARIES = 0x55BB;
    private static final int ID_MAX_CLL = 0x55BC;
    private static final int ID_MAX_FALL = 0x55BD;
    private static final int ID_MASTERING_METADATA = 0x55D0;
    private static final int ID_PRIMARY_R_CHROMATICITY_X = 0x55D1;
    private static final int ID_PRIMARY_R_CHROMATICITY_Y = 0x55D2;
    private static final int ID_PRIMARY_G_CHROMATICITY_X = 0x55D3;
    private static final int ID_PRIMARY_G_CHROMATICITY_Y = 0x55D4;
    private static final int ID_PRIMARY_B_CHROMATICITY_X = 0x55D5;
    private static final int ID_PRIMARY_B_CHROMATICITY_Y = 0x55D6;
    private static final int ID_WHITE_POINT_CHROMATICITY_X = 0x55D7;
    private static final int ID_WHITE_POINT_CHROMATICITY_Y = 0x55D8;
    private static final int ID_LUMNINANCE_MAX = 0x55D9;
    private static final int ID_LUMNINANCE_MIN = 0x55DA;
  
    /**
     * BlockAddID value for ITU T.35 metadata in a VP9 track. See also
     * https://www.webmproject.org/docs/container/.
     */
    private static final int BLOCK_ADDITIONAL_ID_VP9_ITU_T_35 = 4;
  
    /**
     * BlockAddIdType value for Dolby Vision configuration with profile <= 7. See also
     * https://www.matroska.org/technical/codec_specs.html.
     */
    private static final int BLOCK_ADD_ID_TYPE_DVCC = 0x64766343;
    /**
     * BlockAddIdType value for Dolby Vision configuration with profile > 7. See also
     * https://www.matroska.org/technical/codec_specs.html.
     */
    private static final int BLOCK_ADD_ID_TYPE_DVVC = 0x64767643;
  
    private static final int LACING_NONE = 0;
    private static final int LACING_XIPH = 1;
    private static final int LACING_FIXED_SIZE = 2;
    private static final int LACING_EBML = 3;
  
    private static final int FOURCC_COMPRESSION_DIVX = 0x58564944;
    private static final int FOURCC_COMPRESSION_H263 = 0x33363248;
    private static final int FOURCC_COMPRESSION_VC1 = 0x31435657;
  
    /**
     * A template for the prefix that must be added to each subrip sample.
     *
     * <p>The display time of each subtitle is passed as {@code timeUs} to {@link
     * TrackOutput#sampleMetadata}. The start and end timecodes in this template are relative to
     * {@code timeUs}. Hence the start timecode is always zero. The 12 byte end timecode starting at
     * {@link #SUBRIP_PREFIX_END_TIMECODE_OFFSET} is set to a placeholder value, and must be replaced
     * with the duration of the subtitle.
     *
     * <p>Equivalent to the UTF-8 string: "1\n00:00:00,000 --> 00:00:00,000\n".
     */
    private static final byte[] SUBRIP_PREFIX =
        new byte[] {
          49, 10, 48, 48, 58, 48, 48, 58, 48, 48, 44, 48, 48, 48, 32, 45, 45, 62, 32, 48, 48, 58, 48,
          48, 58, 48, 48, 44, 48, 48, 48, 10
        };
    /** The byte offset of the end timecode in {@link #SUBRIP_PREFIX}. */
    private static final int SUBRIP_PREFIX_END_TIMECODE_OFFSET = 19;
    /**
     * The value by which to divide a time in microseconds to convert it to the unit of the last value
     * in a subrip timecode (milliseconds).
     */
    private static final long SUBRIP_TIMECODE_LAST_VALUE_SCALING_FACTOR = 1000;
    /** The format of a subrip timecode. */
    private static final String SUBRIP_TIMECODE_FORMAT = "%02d:%02d:%02d,%03d";
  
    /** Matroska specific format line for SSA subtitles. */
    private static final byte[] SSA_DIALOGUE_FORMAT =
        Util.getUtf8Bytes(
            "Format: Start, End, "
                + "ReadOrder, Layer, Style, Name, MarginL, MarginR, MarginV, Effect, Text");
    /**
     * A template for the prefix that must be added to each SSA sample.
     *
     * <p>The display time of each subtitle is passed as {@code timeUs} to {@link
     * TrackOutput#sampleMetadata}. The start and end timecodes in this template are relative to
     * {@code timeUs}. Hence the start timecode is always zero. The 12 byte end timecode starting at
     * {@link #SUBRIP_PREFIX_END_TIMECODE_OFFSET} is set to a placeholder value, and must be replaced
     * with the duration of the subtitle.
     *
     * <p>Equivalent to the UTF-8 string: "Dialogue: 0:00:00:00,0:00:00:00,".
     */
    private static final byte[] SSA_PREFIX =
        new byte[] {
          68, 105, 97, 108, 111, 103, 117, 101, 58, 32, 48, 58, 48, 48, 58, 48, 48, 58, 48, 48, 44,
          48, 58, 48, 48, 58, 48, 48, 58, 48, 48, 44
        };
    /** The byte offset of the end timecode in {@link #SSA_PREFIX}. */
    private static final int SSA_PREFIX_END_TIMECODE_OFFSET = 21;
    /**
     * The value by which to divide a time in microseconds to convert it to the unit of the last value
     * in an SSA timecode (1/100ths of a second).
     */
    private static final long SSA_TIMECODE_LAST_VALUE_SCALING_FACTOR = 10_000;
    /** The format of an SSA timecode. */
    private static final String SSA_TIMECODE_FORMAT = "%01d:%02d:%02d:%02d";
  
    /**
     * A template for the prefix that must be added to each VTT sample.
     *
     * <p>The display time of each subtitle is passed as {@code timeUs} to {@link
     * TrackOutput#sampleMetadata}. The start and end timecodes in this template are relative to
     * {@code timeUs}. Hence the start timecode is always zero. The 12 byte end timecode starting at
     * {@link #VTT_PREFIX_END_TIMECODE_OFFSET} is set to a placeholder value, and must be replaced
     * with the duration of the subtitle.
     *
     * <p>Equivalent to the UTF-8 string: "WEBVTT\n\n00:00:00.000 --> 00:00:00.000\n".
     */
    private static final byte[] VTT_PREFIX =
        new byte[] {
          87, 69, 66, 86, 84, 84, 10, 10, 48, 48, 58, 48, 48, 58, 48, 48, 46, 48, 48, 48, 32, 45, 45,
          62, 32, 48, 48, 58, 48, 48, 58, 48, 48, 46, 48, 48, 48, 10
        };
    /** The byte offset of the end timecode in {@link #VTT_PREFIX}. */
    private static final int VTT_PREFIX_END_TIMECODE_OFFSET = 25;
    /**
     * The value by which to divide a time in microseconds to convert it to the unit of the last value
     * in a VTT timecode (milliseconds).
     */
    private static final long VTT_TIMECODE_LAST_VALUE_SCALING_FACTOR = 1000;
    /** The format of a VTT timecode. */
    private static final String VTT_TIMECODE_FORMAT = "%02d:%02d:%02d.%03d";
  
    /** The length in bytes of a WAVEFORMATEX structure. */
    private static final int WAVE_FORMAT_SIZE = 18;
    /** Format tag indicating a WAVEFORMATEXTENSIBLE structure. */
    private static final int WAVE_FORMAT_EXTENSIBLE = 0xFFFE;
    /** Format tag for PCM. */
    private static final int WAVE_FORMAT_PCM = 1;
    /** Sub format for PCM. */
    private static final UUID WAVE_SUBFORMAT_PCM = new UUID(0x0100000000001000L, 0x800000AA00389B71L);
  
    /** Some HTC devices signal rotation in track names. */
    private static final Map<String, Integer> TRACK_NAME_TO_ROTATION_DEGREES;
  
    static {
      Map<String, Integer> trackNameToRotationDegrees = new HashMap<>();
      trackNameToRotationDegrees.put("htc_video_rotA-000", 0);
      trackNameToRotationDegrees.put("htc_video_rotA-090", 90);
      trackNameToRotationDegrees.put("htc_video_rotA-180", 180);
      trackNameToRotationDegrees.put("htc_video_rotA-270", 270);
      TRACK_NAME_TO_ROTATION_DEGREES = Collections.unmodifiableMap(trackNameToRotationDegrees);
    }
  
    private final EbmlReader reader;
    private final VarintReader varintReader;
    private final SparseArray<Track> tracks;
    private final boolean seekForCuesEnabled;
  
    // Temporary arrays.
    private final ParsableByteArray nalStartCode;
    private final ParsableByteArray nalLength;
    private final ParsableByteArray scratch;
    private final ParsableByteArray vorbisNumPageSamples;
    private final ParsableByteArray seekEntryIdBytes;
    private final ParsableByteArray sampleStrippedBytes;
    private final ParsableByteArray subtitleSample;
    private final ParsableByteArray encryptionInitializationVector;
    private final ParsableByteArray encryptionSubsampleData;
    private final ParsableByteArray supplementalData;
    private @MonotonicNonNull ByteBuffer encryptionSubsampleDataBuffer;
  
    private long segmentContentSize;
    private long segmentContentPosition = C.POSITION_UNSET;
    private long timecodeScale = C.TIME_UNSET;
    private long durationTimecode = C.TIME_UNSET;
    private long durationUs = C.TIME_UNSET;
  
    // The track corresponding to the current TrackEntry element, or null.
    @Nullable private Track currentTrack;
  
    // Whether a seek map has been sent to the output.
    private boolean sentSeekMap;
  
    // Master seek entry related elements.
    private int seekEntryId;
    private long seekEntryPosition;
  
    // Cue related elements.
    private boolean seekForCues;
    private long cuesContentPosition = C.POSITION_UNSET;
    private long seekPositionAfterBuildingCues = C.POSITION_UNSET;
    private long clusterTimecodeUs = C.TIME_UNSET;
    @Nullable private LongArray cueTimesUs;
    @Nullable private LongArray cueClusterPositions;
    private boolean seenClusterPositionForCurrentCuePoint;
  
    // Reading state.
    private boolean haveOutputSample;
  
    // Block reading state.
    private int blockState;
    private long blockTimeUs;
    private long blockDurationUs;
    private int blockSampleIndex;
    private int blockSampleCount;
    private int[] blockSampleSizes;
    private int blockTrackNumber;
    private int blockTrackNumberLength;
    private @C.BufferFlags int blockFlags;
    private int blockAdditionalId;
    private boolean blockHasReferenceBlock;
    private long blockGroupDiscardPaddingNs;
  
    // Sample writing state.
    private int sampleBytesRead;
    private int sampleBytesWritten;
    private int sampleCurrentNalBytesRemaining;
    private boolean sampleEncodingHandled;
    private boolean sampleSignalByteRead;
    private boolean samplePartitionCountRead;
    private int samplePartitionCount;
    private byte sampleSignalByte;
    private boolean sampleInitializationVectorRead;
  
    // Extractor outputs.
    private @MonotonicNonNull ExtractorOutput extractorOutput;
  
    public MatroskaExtractor() {
      this(0);
    }
  
    public MatroskaExtractor(@Flags int flags) {
      this(new DefaultEbmlReader(), flags);
    }
  
    /* package */ MatroskaExtractor(EbmlReader reader, @Flags int flags) {
      this.reader = reader;
      this.reader.init(new InnerEbmlProcessor());
      seekForCuesEnabled = (flags & FLAG_DISABLE_SEEK_FOR_CUES) == 0;
      varintReader = new VarintReader();
      tracks = new SparseArray<>();
      scratch = new ParsableByteArray(4);
      vorbisNumPageSamples = new ParsableByteArray(ByteBuffer.allocate(4).putInt(-1).array());
      seekEntryIdBytes = new ParsableByteArray(4);
      nalStartCode = new ParsableByteArray(NalUnitUtil.NAL_START_CODE);
      nalLength = new ParsableByteArray(4);
      sampleStrippedBytes = new ParsableByteArray();
      subtitleSample = new ParsableByteArray();
      encryptionInitializationVector = new ParsableByteArray(ENCRYPTION_IV_SIZE);
      encryptionSubsampleData = new ParsableByteArray();
      supplementalData = new ParsableByteArray();
      blockSampleSizes = new int[1];
    }
  
    @Override
    public final boolean sniff(ExtractorInput input) throws IOException {
      return new Sniffer().sniff(input);
    }
  
    @Override
    public final void init(ExtractorOutput output) {
      extractorOutput = output;
    }
  
    @CallSuper
    @Override
    public void seek(long position, long timeUs) {
      clusterTimecodeUs = C.TIME_UNSET;
      blockState = BLOCK_STATE_START;
      reader.reset();
      varintReader.reset();
      resetWriteSampleData();
      for (int i = 0; i < tracks.size(); i++) {
        tracks.valueAt(i).reset();
      }
    }
  
    @Override
    public final void release() {
      // Do nothing
    }
  
    @Override
    public final int read(ExtractorInput input, PositionHolder seekPosition) throws IOException {
      haveOutputSample = false;
      boolean continueReading = true;
      while (continueReading && !haveOutputSample) {
        continueReading = reader.read(input);
        if (continueReading && maybeSeekForCues(seekPosition, input.getPosition())) {
          return Extractor.RESULT_SEEK;
        }
      }
      if (!continueReading) {
        for (int i = 0; i < tracks.size(); i++) {
          Track track = tracks.valueAt(i);
          track.assertOutputInitialized();
          track.outputPendingSampleMetadata();
        }
        return Extractor.RESULT_END_OF_INPUT;
      }
      return Extractor.RESULT_CONTINUE;
    }
  
    /**
     * Maps an element ID to a corresponding type.
     *
     * @see EbmlProcessor#getElementType(int)
     */
    @CallSuper
    protected @EbmlProcessor.ElementType int getElementType(int id) {
      switch (id) {
        case ID_EBML:
        case ID_SEGMENT:
        case ID_SEEK_HEAD:
        case ID_SEEK:
        case ID_INFO:
        case ID_CLUSTER:
        case ID_TRACKS:
        case ID_TRACK_ENTRY:
        case ID_BLOCK_ADDITION_MAPPING:
        case ID_AUDIO:
        case ID_VIDEO:
        case ID_CONTENT_ENCODINGS:
        case ID_CONTENT_ENCODING:
        case ID_CONTENT_COMPRESSION:
        case ID_CONTENT_ENCRYPTION:
        case ID_CONTENT_ENCRYPTION_AES_SETTINGS:
        case ID_CUES:
        case ID_CUE_POINT:
        case ID_CUE_TRACK_POSITIONS:
        case ID_BLOCK_GROUP:
        case ID_BLOCK_ADDITIONS:
        case ID_BLOCK_MORE:
        case ID_PROJECTION:
        case ID_COLOUR:
        case ID_MASTERING_METADATA:
          return EbmlProcessor.ELEMENT_TYPE_MASTER;
        case ID_EBML_READ_VERSION:
        case ID_DOC_TYPE_READ_VERSION:
        case ID_SEEK_POSITION:
        case ID_TIMECODE_SCALE:
        case ID_TIME_CODE:
        case ID_BLOCK_DURATION:
        case ID_PIXEL_WIDTH:
        case ID_PIXEL_HEIGHT:
        case ID_DISPLAY_WIDTH:
        case ID_DISPLAY_HEIGHT:
        case ID_DISPLAY_UNIT:
        case ID_TRACK_NUMBER:
        case ID_TRACK_TYPE:
        case ID_FLAG_DEFAULT:
        case ID_FLAG_FORCED:
        case ID_DEFAULT_DURATION:
        case ID_MAX_BLOCK_ADDITION_ID:
        case ID_BLOCK_ADD_ID_TYPE:
        case ID_CODEC_DELAY:
        case ID_SEEK_PRE_ROLL:
        case ID_DISCARD_PADDING:
        case ID_CHANNELS:
        case ID_AUDIO_BIT_DEPTH:
        case ID_CONTENT_ENCODING_ORDER:
        case ID_CONTENT_ENCODING_SCOPE:
        case ID_CONTENT_COMPRESSION_ALGORITHM:
        case ID_CONTENT_ENCRYPTION_ALGORITHM:
        case ID_CONTENT_ENCRYPTION_AES_SETTINGS_CIPHER_MODE:
        case ID_CUE_TIME:
        case ID_CUE_CLUSTER_POSITION:
        case ID_REFERENCE_BLOCK:
        case ID_STEREO_MODE:
        case ID_COLOUR_RANGE:
        case ID_COLOUR_TRANSFER:
        case ID_COLOUR_PRIMARIES:
        case ID_MAX_CLL:
        case ID_MAX_FALL:
        case ID_PROJECTION_TYPE:
        case ID_BLOCK_ADD_ID:
          return EbmlProcessor.ELEMENT_TYPE_UNSIGNED_INT;
        case ID_DOC_TYPE:
        case ID_NAME:
        case ID_CODEC_ID:
        case ID_LANGUAGE:
          return EbmlProcessor.ELEMENT_TYPE_STRING;
        case ID_SEEK_ID:
        case ID_BLOCK_ADD_ID_EXTRA_DATA:
        case ID_CONTENT_COMPRESSION_SETTINGS:
        case ID_CONTENT_ENCRYPTION_KEY_ID:
        case ID_SIMPLE_BLOCK:
        case ID_BLOCK:
        case ID_CODEC_PRIVATE:
        case ID_PROJECTION_PRIVATE:
        case ID_BLOCK_ADDITIONAL:
          return EbmlProcessor.ELEMENT_TYPE_BINARY;
        case ID_DURATION:
        case ID_SAMPLING_FREQUENCY:
        case ID_PRIMARY_R_CHROMATICITY_X:
        case ID_PRIMARY_R_CHROMATICITY_Y:
        case ID_PRIMARY_G_CHROMATICITY_X:
        case ID_PRIMARY_G_CHROMATICITY_Y:
        case ID_PRIMARY_B_CHROMATICITY_X:
        case ID_PRIMARY_B_CHROMATICITY_Y:
        case ID_WHITE_POINT_CHROMATICITY_X:
        case ID_WHITE_POINT_CHROMATICITY_Y:
        case ID_LUMNINANCE_MAX:
        case ID_LUMNINANCE_MIN:
        case ID_PROJECTION_POSE_YAW:
        case ID_PROJECTION_POSE_PITCH:
        case ID_PROJECTION_POSE_ROLL:
          return EbmlProcessor.ELEMENT_TYPE_FLOAT;
        default:
          return EbmlProcessor.ELEMENT_TYPE_UNKNOWN;
      }
    }
  
    /**
     * Checks if the given id is that of a level 1 element.
     *
     * @see EbmlProcessor#isLevel1Element(int)
     */
    @CallSuper
    protected boolean isLevel1Element(int id) {
      return id == ID_SEGMENT_INFO || id == ID_CLUSTER || id == ID_CUES || id == ID_TRACKS;
    }
  
    /**
     * Called when the start of a master element is encountered.
     *
     * @see EbmlProcessor#startMasterElement(int, long, long)
     */
    @CallSuper
    protected void startMasterElement(int id, long contentPosition, long contentSize)
        throws ParserException {
      assertInitialized();
      switch (id) {
        case ID_SEGMENT:
          if (segmentContentPosition != C.POSITION_UNSET
              && segmentContentPosition != contentPosition) {
            throw ParserException.createForMalformedContainer(
                "Multiple Segment elements not supported", /* cause= */ null);
          }
          segmentContentPosition = contentPosition;
          segmentContentSize = contentSize;
          break;
        case ID_SEEK:
          seekEntryId = UNSET_ENTRY_ID;
          seekEntryPosition = C.POSITION_UNSET;
          break;
        case ID_CUES:
          cueTimesUs = new LongArray();
          cueClusterPositions = new LongArray();
          break;
        case ID_CUE_POINT:
          seenClusterPositionForCurrentCuePoint = false;
          break;
        case ID_CLUSTER:
          if (!sentSeekMap) {
            // We need to build cues before parsing the cluster.
            if (seekForCuesEnabled && cuesContentPosition != C.POSITION_UNSET) {
              // We know where the Cues element is located. Seek to request it.
              seekForCues = true;
            } else {
              // We don't know where the Cues element is located. It's most likely omitted. Allow
              // playback, but disable seeking.
              extractorOutput.seekMap(new SeekMap.Unseekable(durationUs));
              sentSeekMap = true;
            }
          }
          break;
        case ID_BLOCK_GROUP:
          blockHasReferenceBlock = false;
          blockGroupDiscardPaddingNs = 0L;
          break;
        case ID_CONTENT_ENCODING:
          // TODO: check and fail if more than one content encoding is present.
          break;
        case ID_CONTENT_ENCRYPTION:
          getCurrentTrack(id).hasContentEncryption = true;
          break;
        case ID_TRACK_ENTRY:
          currentTrack = new Track();
          break;
        case ID_MASTERING_METADATA:
          getCurrentTrack(id).hasColorInfo = true;
          break;
        default:
          break;
      }
    }
  
    /**
     * Called when the end of a master element is encountered.
     *
     * @see EbmlProcessor#endMasterElement(int)
     */
    @CallSuper
    protected void endMasterElement(int id) throws ParserException {
      assertInitialized();
      switch (id) {
        case ID_SEGMENT_INFO:
          if (timecodeScale == C.TIME_UNSET) {
            // timecodeScale was omitted. Use the default value.
            timecodeScale = 1000000;
          }
          if (durationTimecode != C.TIME_UNSET) {
            durationUs = scaleTimecodeToUs(durationTimecode);
          }
          break;
        case ID_SEEK:
          if (seekEntryId == UNSET_ENTRY_ID || seekEntryPosition == C.POSITION_UNSET) {
            throw ParserException.createForMalformedContainer(
                "Mandatory element SeekID or SeekPosition not found", /* cause= */ null);
          }
          if (seekEntryId == ID_CUES) {
            cuesContentPosition = seekEntryPosition;
          }
          break;
        case ID_CUES:
          if (!sentSeekMap) {
            extractorOutput.seekMap(buildSeekMap(cueTimesUs, cueClusterPositions));
            sentSeekMap = true;
          } else {
            // We have already built the cues. Ignore.
          }
          this.cueTimesUs = null;
          this.cueClusterPositions = null;
          break;
        case ID_BLOCK_GROUP:
          if (blockState != BLOCK_STATE_DATA) {
            // We've skipped this block (due to incompatible track number).
            return;
          }
          Track track = tracks.get(blockTrackNumber);
          track.assertOutputInitialized();
          if (blockGroupDiscardPaddingNs > 0L && CODEC_ID_OPUS.equals(track.codecId)) {
            // For Opus, attach DiscardPadding to the block group samples as supplemental data.
            supplementalData.reset(
                ByteBuffer.allocate(8)
                    .order(ByteOrder.LITTLE_ENDIAN)
                    .putLong(blockGroupDiscardPaddingNs)
                    .array());
          }
  
          // Commit sample metadata.
          int sampleOffset = 0;
          for (int i = 0; i < blockSampleCount; i++) {
            sampleOffset += blockSampleSizes[i];
          }
          for (int i = 0; i < blockSampleCount; i++) {
            long sampleTimeUs = blockTimeUs + (i * track.defaultSampleDurationNs) / 1000;
            int sampleFlags = blockFlags;
            if (i == 0 && !blockHasReferenceBlock) {
              // If the ReferenceBlock element was not found in this block, then the first frame is a
              // keyframe.
              sampleFlags |= C.BUFFER_FLAG_KEY_FRAME;
            }
            int sampleSize = blockSampleSizes[i];
            sampleOffset -= sampleSize; // The offset is to the end of the sample.
            commitSampleToOutput(track, sampleTimeUs, sampleFlags, sampleSize, sampleOffset);
          }
          blockState = BLOCK_STATE_START;
          break;
        case ID_CONTENT_ENCODING:
          assertInTrackEntry(id);
          if (currentTrack.hasContentEncryption) {
            if (currentTrack.cryptoData == null) {
              throw ParserException.createForMalformedContainer(
                  "Encrypted Track found but ContentEncKeyID was not found", /* cause= */ null);
            }
            currentTrack.drmInitData =
                new DrmInitData(
                    new SchemeData(
                        C.UUID_NIL, MimeTypes.VIDEO_WEBM, currentTrack.cryptoData.encryptionKey));
          }
          break;
        case ID_CONTENT_ENCODINGS:
          assertInTrackEntry(id);
          if (currentTrack.hasContentEncryption && currentTrack.sampleStrippedBytes != null) {
            throw ParserException.createForMalformedContainer(
                "Combining encryption and compression is not supported", /* cause= */ null);
          }
          break;
        case ID_TRACK_ENTRY:
          Track currentTrack = checkStateNotNull(this.currentTrack);
          if (currentTrack.codecId == null) {
            throw ParserException.createForMalformedContainer(
                "CodecId is missing in TrackEntry element", /* cause= */ null);
          } else {
            if (isCodecSupported(currentTrack.codecId)) {
              currentTrack.initializeOutput(extractorOutput, currentTrack.number);
              tracks.put(currentTrack.number, currentTrack);
            }
          }
          this.currentTrack = null;
          break;
        case ID_TRACKS:
          if (tracks.size() == 0) {
            throw ParserException.createForMalformedContainer(
                "No valid tracks were found", /* cause= */ null);
          }
          extractorOutput.endTracks();
          break;
        default:
          break;
      }
    }
  
    /**
     * Called when an integer element is encountered.
     *
     * @see EbmlProcessor#integerElement(int, long)
     */
    @CallSuper
    protected void integerElement(int id, long value) throws ParserException {
      switch (id) {
        case ID_EBML_READ_VERSION:
          // Validate that EBMLReadVersion is supported. This extractor only supports v1.
          if (value != 1) {
            throw ParserException.createForMalformedContainer(
                "EBMLReadVersion " + value + " not supported", /* cause= */ null);
          }
          break;
        case ID_DOC_TYPE_READ_VERSION:
          // Validate that DocTypeReadVersion is supported. This extractor only supports up to v2.
          if (value < 1 || value > 2) {
            throw ParserException.createForMalformedContainer(
                "DocTypeReadVersion " + value + " not supported", /* cause= */ null);
          }
          break;
        case ID_SEEK_POSITION:
          // Seek Position is the relative offset beginning from the Segment. So to get absolute
          // offset from the beginning of the file, we need to add segmentContentPosition to it.
          seekEntryPosition = value + segmentContentPosition;
          break;
        case ID_TIMECODE_SCALE:
          timecodeScale = value;
          break;
        case ID_PIXEL_WIDTH:
          getCurrentTrack(id).width = (int) value;
          break;
        case ID_PIXEL_HEIGHT:
          getCurrentTrack(id).height = (int) value;
          break;
        case ID_DISPLAY_WIDTH:
          getCurrentTrack(id).displayWidth = (int) value;
          break;
        case ID_DISPLAY_HEIGHT:
          getCurrentTrack(id).displayHeight = (int) value;
          break;
        case ID_DISPLAY_UNIT:
          getCurrentTrack(id).displayUnit = (int) value;
          break;
        case ID_TRACK_NUMBER:
          getCurrentTrack(id).number = (int) value;
          break;
        case ID_FLAG_DEFAULT:
          getCurrentTrack(id).flagDefault = value == 1;
          break;
        case ID_FLAG_FORCED:
          getCurrentTrack(id).flagForced = value == 1;
          break;
        case ID_TRACK_TYPE:
          getCurrentTrack(id).type = (int) value;
          break;
        case ID_DEFAULT_DURATION:
          getCurrentTrack(id).defaultSampleDurationNs = (int) value;
          break;
        case ID_MAX_BLOCK_ADDITION_ID:
          getCurrentTrack(id).maxBlockAdditionId = (int) value;
          break;
        case ID_BLOCK_ADD_ID_TYPE:
          getCurrentTrack(id).blockAddIdType = (int) value;
          break;
        case ID_CODEC_DELAY:
          getCurrentTrack(id).codecDelayNs = value;
          break;
        case ID_SEEK_PRE_ROLL:
          getCurrentTrack(id).seekPreRollNs = value;
          break;
        case ID_DISCARD_PADDING:
          blockGroupDiscardPaddingNs = value;
          break;
        case ID_CHANNELS:
          getCurrentTrack(id).channelCount = (int) value;
          break;
        case ID_AUDIO_BIT_DEPTH:
          getCurrentTrack(id).audioBitDepth = (int) value;
          break;
        case ID_REFERENCE_BLOCK:
          blockHasReferenceBlock = true;
          break;
        case ID_CONTENT_ENCODING_ORDER:
          // This extractor only supports one ContentEncoding element and hence the order has to be 0.
          if (value != 0) {
            throw ParserException.createForMalformedContainer(
                "ContentEncodingOrder " + value + " not supported", /* cause= */ null);
          }
          break;
        case ID_CONTENT_ENCODING_SCOPE:
          // This extractor only supports the scope of all frames.
          if (value != 1) {
            throw ParserException.createForMalformedContainer(
                "ContentEncodingScope " + value + " not supported", /* cause= */ null);
          }
          break;
        case ID_CONTENT_COMPRESSION_ALGORITHM:
          // This extractor only supports header stripping.
          if (value != 3) {
            throw ParserException.createForMalformedContainer(
                "ContentCompAlgo " + value + " not supported", /* cause= */ null);
          }
          break;
        case ID_CONTENT_ENCRYPTION_ALGORITHM:
          // Only the value 5 (AES) is allowed according to the WebM specification.
          if (value != 5) {
            throw ParserException.createForMalformedContainer(
                "ContentEncAlgo " + value + " not supported", /* cause= */ null);
          }
          break;
        case ID_CONTENT_ENCRYPTION_AES_SETTINGS_CIPHER_MODE:
          // Only the value 1 is allowed according to the WebM specification.
          if (value != 1) {
            throw ParserException.createForMalformedContainer(
                "AESSettingsCipherMode " + value + " not supported", /* cause= */ null);
          }
          break;
        case ID_CUE_TIME:
          assertInCues(id);
          cueTimesUs.add(scaleTimecodeToUs(value));
          break;
        case ID_CUE_CLUSTER_POSITION:
          if (!seenClusterPositionForCurrentCuePoint) {
            assertInCues(id);
            // If there's more than one video/audio track, then there could be more than one
            // CueTrackPositions within a single CuePoint. In such a case, ignore all but the first
            // one (since the cluster position will be quite close for all the tracks).
            cueClusterPositions.add(value);
            seenClusterPositionForCurrentCuePoint = true;
          }
          break;
        case ID_TIME_CODE:
          clusterTimecodeUs = scaleTimecodeToUs(value);
          break;
        case ID_BLOCK_DURATION:
          blockDurationUs = scaleTimecodeToUs(value);
          break;
        case ID_STEREO_MODE:
          int layout = (int) value;
          assertInTrackEntry(id);
          switch (layout) {
            case 0:
              currentTrack.stereoMode = C.STEREO_MODE_MONO;
              break;
            case 1:
              currentTrack.stereoMode = C.STEREO_MODE_LEFT_RIGHT;
              break;
            case 3:
              currentTrack.stereoMode = C.STEREO_MODE_TOP_BOTTOM;
              break;
            case 15:
              currentTrack.stereoMode = C.STEREO_MODE_STEREO_MESH;
              break;
            default:
              break;
          }
          break;
        case ID_COLOUR_PRIMARIES:
          assertInTrackEntry(id);
          currentTrack.hasColorInfo = true;
          int colorSpace = ColorInfo.isoColorPrimariesToColorSpace((int) value);
          if (colorSpace != Format.NO_VALUE) {
            currentTrack.colorSpace = colorSpace;
          }
          break;
        case ID_COLOUR_TRANSFER:
          assertInTrackEntry(id);
          int colorTransfer = ColorInfo.isoTransferCharacteristicsToColorTransfer((int) value);
          if (colorTransfer != Format.NO_VALUE) {
            currentTrack.colorTransfer = colorTransfer;
          }
          break;
        case ID_COLOUR_RANGE:
          assertInTrackEntry(id);
          switch ((int) value) {
            case 1: // Broadcast range.
              currentTrack.colorRange = C.COLOR_RANGE_LIMITED;
              break;
            case 2:
              currentTrack.colorRange = C.COLOR_RANGE_FULL;
              break;
            default:
              break;
          }
          break;
        case ID_MAX_CLL:
          getCurrentTrack(id).maxContentLuminance = (int) value;
          break;
        case ID_MAX_FALL:
          getCurrentTrack(id).maxFrameAverageLuminance = (int) value;
          break;
        case ID_PROJECTION_TYPE:
          assertInTrackEntry(id);
          switch ((int) value) {
            case 0:
              currentTrack.projectionType = C.PROJECTION_RECTANGULAR;
              break;
            case 1:
              currentTrack.projectionType = C.PROJECTION_EQUIRECTANGULAR;
              break;
            case 2:
              currentTrack.projectionType = C.PROJECTION_CUBEMAP;
              break;
            case 3:
              currentTrack.projectionType = C.PROJECTION_MESH;
              break;
            default:
              break;
          }
          break;
        case ID_BLOCK_ADD_ID:
          blockAdditionalId = (int) value;
          break;
        default:
          break;
      }
    }
  
    /**
     * Called when a float element is encountered.
     *
     * @see EbmlProcessor#floatElement(int, double)
     */
    @CallSuper
    protected void floatElement(int id, double value) throws ParserException {
      switch (id) {
        case ID_DURATION:
          durationTimecode = (long) value;
          break;
        case ID_SAMPLING_FREQUENCY:
          getCurrentTrack(id).sampleRate = (int) value;
          break;
        case ID_PRIMARY_R_CHROMATICITY_X:
          getCurrentTrack(id).primaryRChromaticityX = (float) value;
          break;
        case ID_PRIMARY_R_CHROMATICITY_Y:
          getCurrentTrack(id).primaryRChromaticityY = (float) value;
          break;
        case ID_PRIMARY_G_CHROMATICITY_X:
          getCurrentTrack(id).primaryGChromaticityX = (float) value;
          break;
        case ID_PRIMARY_G_CHROMATICITY_Y:
          getCurrentTrack(id).primaryGChromaticityY = (float) value;
          break;
        case ID_PRIMARY_B_CHROMATICITY_X:
          getCurrentTrack(id).primaryBChromaticityX = (float) value;
          break;
        case ID_PRIMARY_B_CHROMATICITY_Y:
          getCurrentTrack(id).primaryBChromaticityY = (float) value;
          break;
        case ID_WHITE_POINT_CHROMATICITY_X:
          getCurrentTrack(id).whitePointChromaticityX = (float) value;
          break;
        case ID_WHITE_POINT_CHROMATICITY_Y:
          getCurrentTrack(id).whitePointChromaticityY = (float) value;
          break;
        case ID_LUMNINANCE_MAX:
          getCurrentTrack(id).maxMasteringLuminance = (float) value;
          break;
        case ID_LUMNINANCE_MIN:
          getCurrentTrack(id).minMasteringLuminance = (float) value;
          break;
        case ID_PROJECTION_POSE_YAW:
          getCurrentTrack(id).projectionPoseYaw = (float) value;
          break;
        case ID_PROJECTION_POSE_PITCH:
          getCurrentTrack(id).projectionPosePitch = (float) value;
          break;
        case ID_PROJECTION_POSE_ROLL:
          getCurrentTrack(id).projectionPoseRoll = (float) value;
          break;
        default:
          break;
      }
    }
  
    /**
     * Called when a string element is encountered.
     *
     * @see EbmlProcessor#stringElement(int, String)
     */
    @CallSuper
    protected void stringElement(int id, String value) throws ParserException {
      switch (id) {
        case ID_DOC_TYPE:
          // Validate that DocType is supported.
          if (!DOC_TYPE_WEBM.equals(value) && !DOC_TYPE_MATROSKA.equals(value)) {
            throw ParserException.createForMalformedContainer(
                "DocType " + value + " not supported", /* cause= */ null);
          }
          break;
        case ID_NAME:
          getCurrentTrack(id).name = value;
          break;
        case ID_CODEC_ID:
          getCurrentTrack(id).codecId = value;
          break;
        case ID_LANGUAGE:
          getCurrentTrack(id).language = value;
          break;
        default:
          break;
      }
    }
  
    /**
     * Called when a binary element is encountered.
     *
     * @see EbmlProcessor#binaryElement(int, int, ExtractorInput)
     */
    @CallSuper
    protected void binaryElement(int id, int contentSize, ExtractorInput input) throws IOException {
      switch (id) {
        case ID_SEEK_ID:
          Arrays.fill(seekEntryIdBytes.getData(), (byte) 0);
          input.readFully(seekEntryIdBytes.getData(), 4 - contentSize, contentSize);
          seekEntryIdBytes.setPosition(0);
          seekEntryId = (int) seekEntryIdBytes.readUnsignedInt();
          break;
        case ID_BLOCK_ADD_ID_EXTRA_DATA:
          handleBlockAddIDExtraData(getCurrentTrack(id), input, contentSize);
          break;
        case ID_CODEC_PRIVATE:
          assertInTrackEntry(id);
          currentTrack.codecPrivate = new byte[contentSize];
          input.readFully(currentTrack.codecPrivate, 0, contentSize);
          break;
        case ID_PROJECTION_PRIVATE:
          assertInTrackEntry(id);
          currentTrack.projectionData = new byte[contentSize];
          input.readFully(currentTrack.projectionData, 0, contentSize);
          break;
        case ID_CONTENT_COMPRESSION_SETTINGS:
          assertInTrackEntry(id);
          // This extractor only supports header stripping, so the payload is the stripped bytes.
          currentTrack.sampleStrippedBytes = new byte[contentSize];
          input.readFully(currentTrack.sampleStrippedBytes, 0, contentSize);
          break;
        case ID_CONTENT_ENCRYPTION_KEY_ID:
          byte[] encryptionKey = new byte[contentSize];
          input.readFully(encryptionKey, 0, contentSize);
          getCurrentTrack(id).cryptoData =
              new TrackOutput.CryptoData(
                  C.CRYPTO_MODE_AES_CTR, encryptionKey, 0, 0); // We assume patternless AES-CTR.
          break;
        case ID_SIMPLE_BLOCK:
        case ID_BLOCK:
          // Please refer to http://www.matroska.org/technical/specs/index.html#simpleblock_structure
          // and http://matroska.org/technical/specs/index.html#block_structure
          // for info about how data is organized in SimpleBlock and Block elements respectively. They
          // differ only in the way flags are specified.
  
          if (blockState == BLOCK_STATE_START) {
            blockTrackNumber = (int) varintReader.readUnsignedVarint(input, false, true, 8);
            blockTrackNumberLength = varintReader.getLastLength();
            blockDurationUs = C.TIME_UNSET;
            blockState = BLOCK_STATE_HEADER;
            scratch.reset(/* limit= */ 0);
          }
  
          Track track = tracks.get(blockTrackNumber);
  
          // Ignore the block if we don't know about the track to which it belongs.
          if (track == null) {
            input.skipFully(contentSize - blockTrackNumberLength);
            blockState = BLOCK_STATE_START;
            return;
          }
  
          track.assertOutputInitialized();
  
          if (blockState == BLOCK_STATE_HEADER) {
            // Read the relative timecode (2 bytes) and flags (1 byte).
            readScratch(input, 3);
            int lacing = (scratch.getData()[2] & 0x06) >> 1;
            if (lacing == LACING_NONE) {
              blockSampleCount = 1;
              blockSampleSizes = ensureArrayCapacity(blockSampleSizes, 1);
              blockSampleSizes[0] = contentSize - blockTrackNumberLength - 3;
            } else {
              // Read the sample count (1 byte).
              readScratch(input, 4);
              blockSampleCount = (scratch.getData()[3] & 0xFF) + 1;
              blockSampleSizes = ensureArrayCapacity(blockSampleSizes, blockSampleCount);
              if (lacing == LACING_FIXED_SIZE) {
                int blockLacingSampleSize =
                    (contentSize - blockTrackNumberLength - 4) / blockSampleCount;
                Arrays.fill(blockSampleSizes, 0, blockSampleCount, blockLacingSampleSize);
              } else if (lacing == LACING_XIPH) {
                int totalSamplesSize = 0;
                int headerSize = 4;
                for (int sampleIndex = 0; sampleIndex < blockSampleCount - 1; sampleIndex++) {
                  blockSampleSizes[sampleIndex] = 0;
                  int byteValue;
                  do {
                    readScratch(input, ++headerSize);
                    byteValue = scratch.getData()[headerSize - 1] & 0xFF;
                    blockSampleSizes[sampleIndex] += byteValue;
                  } while (byteValue == 0xFF);
                  totalSamplesSize += blockSampleSizes[sampleIndex];
                }
                blockSampleSizes[blockSampleCount - 1] =
                    contentSize - blockTrackNumberLength - headerSize - totalSamplesSize;
              } else if (lacing == LACING_EBML) {
                int totalSamplesSize = 0;
                int headerSize = 4;
                for (int sampleIndex = 0; sampleIndex < blockSampleCount - 1; sampleIndex++) {
                  blockSampleSizes[sampleIndex] = 0;
                  readScratch(input, ++headerSize);
                  if (scratch.getData()[headerSize - 1] == 0) {
                    throw ParserException.createForMalformedContainer(
                        "No valid varint length mask found", /* cause= */ null);
                  }
                  long readValue = 0;
                  for (int i = 0; i < 8; i++) {
                    int lengthMask = 1 << (7 - i);
                    if ((scratch.getData()[headerSize - 1] & lengthMask) != 0) {
                      int readPosition = headerSize - 1;
                      headerSize += i;
                      readScratch(input, headerSize);
                      readValue = (scratch.getData()[readPosition++] & 0xFF) & ~lengthMask;
                      while (readPosition < headerSize) {
                        readValue <<= 8;
                        readValue |= (scratch.getData()[readPosition++] & 0xFF);
                      }
                      // The first read value is the first size. Later values are signed offsets.
                      if (sampleIndex > 0) {
                        readValue -= (1L << (6 + i * 7)) - 1;
                      }
                      break;
                    }
                  }
                  if (readValue < Integer.MIN_VALUE || readValue > Integer.MAX_VALUE) {
                    throw ParserException.createForMalformedContainer(
                        "EBML lacing sample size out of range.", /* cause= */ null);
                  }
                  int intReadValue = (int) readValue;
                  blockSampleSizes[sampleIndex] =
                      sampleIndex == 0
                          ? intReadValue
                          : blockSampleSizes[sampleIndex - 1] + intReadValue;
                  totalSamplesSize += blockSampleSizes[sampleIndex];
                }
                blockSampleSizes[blockSampleCount - 1] =
                    contentSize - blockTrackNumberLength - headerSize - totalSamplesSize;
              } else {
                // Lacing is always in the range 0--3.
                throw ParserException.createForMalformedContainer(
                    "Unexpected lacing value: " + lacing, /* cause= */ null);
              }
            }
  
            int timecode = (scratch.getData()[0] << 8) | (scratch.getData()[1] & 0xFF);
            blockTimeUs = clusterTimecodeUs + scaleTimecodeToUs(timecode);
            boolean isKeyframe =
                track.type == TRACK_TYPE_AUDIO
                    || (id == ID_SIMPLE_BLOCK && (scratch.getData()[2] & 0x80) == 0x80);
            blockFlags = isKeyframe ? C.BUFFER_FLAG_KEY_FRAME : 0;
            blockState = BLOCK_STATE_DATA;
            blockSampleIndex = 0;
          }
  
          if (id == ID_SIMPLE_BLOCK) {
            // For SimpleBlock, we can write sample data and immediately commit the corresponding
            // sample metadata.
            while (blockSampleIndex < blockSampleCount) {
              int sampleSize =
                  writeSampleData(
                      input, track, blockSampleSizes[blockSampleIndex], /* isBlockGroup= */ false);
              long sampleTimeUs =
                  blockTimeUs + (blockSampleIndex * track.defaultSampleDurationNs) / 1000;
              commitSampleToOutput(track, sampleTimeUs, blockFlags, sampleSize, /* offset= */ 0);
              blockSampleIndex++;
            }
            blockState = BLOCK_STATE_START;
          } else {
            // For Block, we need to wait until the end of the BlockGroup element before committing
            // sample metadata. This is so that we can handle ReferenceBlock (which can be used to
            // infer whether the first sample in the block is a keyframe), and BlockAdditions (which
            // can contain additional sample data to append) contained in the block group. Just output
            // the sample data, storing the final sample sizes for when we commit the metadata.
            while (blockSampleIndex < blockSampleCount) {
              blockSampleSizes[blockSampleIndex] =
                  writeSampleData(
                      input, track, blockSampleSizes[blockSampleIndex], /* isBlockGroup= */ true);
              blockSampleIndex++;
            }
          }
  
          break;
        case ID_BLOCK_ADDITIONAL:
          if (blockState != BLOCK_STATE_DATA) {
            return;
          }
          handleBlockAdditionalData(
              tracks.get(blockTrackNumber), blockAdditionalId, input, contentSize);
          break;
        default:
          throw ParserException.createForMalformedContainer(
              "Unexpected id: " + id, /* cause= */ null);
      }
    }
  
    protected void handleBlockAddIDExtraData(Track track, ExtractorInput input, int contentSize)
        throws IOException {
      if (track.blockAddIdType == BLOCK_ADD_ID_TYPE_DVVC
          || track.blockAddIdType == BLOCK_ADD_ID_TYPE_DVCC) {
        track.dolbyVisionConfigBytes = new byte[contentSize];
        input.readFully(track.dolbyVisionConfigBytes, 0, contentSize);
      } else {
        // Unhandled BlockAddIDExtraData.
        input.skipFully(contentSize);
      }
    }
  
    protected void handleBlockAdditionalData(
        Track track, int blockAdditionalId, ExtractorInput input, int contentSize)
        throws IOException {
      if (blockAdditionalId == BLOCK_ADDITIONAL_ID_VP9_ITU_T_35
          && CODEC_ID_VP9.equals(track.codecId)) {
        supplementalData.reset(contentSize);
        input.readFully(supplementalData.getData(), 0, contentSize);
      } else {
        // Unhandled block additional data.
        input.skipFully(contentSize);
      }
    }
  
    @EnsuresNonNull("currentTrack")
    private void assertInTrackEntry(int id) throws ParserException {
      if (currentTrack == null) {
        throw ParserException.createForMalformedContainer(
            "Element " + id + " must be in a TrackEntry", /* cause= */ null);
      }
    }
  
    @EnsuresNonNull({"cueTimesUs", "cueClusterPositions"})
    private void assertInCues(int id) throws ParserException {
      if (cueTimesUs == null || cueClusterPositions == null) {
        throw ParserException.createForMalformedContainer(
            "Element " + id + " must be in a Cues", /* cause= */ null);
      }
    }
  
    /**
     * Returns the track corresponding to the current TrackEntry element.
     *
     * @throws ParserException if the element id is not in a TrackEntry.
     */
    protected Track getCurrentTrack(int currentElementId) throws ParserException {
      assertInTrackEntry(currentElementId);
      return currentTrack;
    }
  
    @RequiresNonNull("#1.output")
    private void commitSampleToOutput(
        Track track, long timeUs, @C.BufferFlags int flags, int size, int offset) {
      if (track.trueHdSampleRechunker != null) {
        track.trueHdSampleRechunker.sampleMetadata(
            track.output, timeUs, flags, size, offset, track.cryptoData);
      } else {
        if (CODEC_ID_SUBRIP.equals(track.codecId)
            || CODEC_ID_ASS.equals(track.codecId)
            || CODEC_ID_VTT.equals(track.codecId)) {
          if (blockSampleCount > 1) {
            Log.w(TAG, "Skipping subtitle sample in laced block.");
          } else if (blockDurationUs == C.TIME_UNSET) {
            Log.w(TAG, "Skipping subtitle sample with no duration.");
          } else {
            setSubtitleEndTime(track.codecId, blockDurationUs, subtitleSample.getData());
            // The Matroska spec doesn't clearly define whether subtitle samples are null-terminated
            // or the sample should instead be sized precisely. We truncate the sample at a null-byte
            // to gracefully handle null-terminated strings followed by garbage bytes.
            for (int i = subtitleSample.getPosition(); i < subtitleSample.limit(); i++) {
              if (subtitleSample.getData()[i] == 0) {
                subtitleSample.setLimit(i);
                break;
              }
            }
            // Note: If we ever want to support DRM protected subtitles then we'll need to output the
            // appropriate encryption data here.
            track.output.sampleData(subtitleSample, subtitleSample.limit());
            size += subtitleSample.limit();
          }
        }
  
        if ((flags & C.BUFFER_FLAG_HAS_SUPPLEMENTAL_DATA) != 0) {
          if (blockSampleCount > 1) {
            // There were multiple samples in the block. Appending the additional data to the last
            // sample doesn't make sense. Skip instead.
            supplementalData.reset(/* limit= */ 0);
          } else {
            // Append supplemental data.
            int supplementalDataSize = supplementalData.limit();
            track.output.sampleData(
                supplementalData, supplementalDataSize, TrackOutput.SAMPLE_DATA_PART_SUPPLEMENTAL);
            size += supplementalDataSize;
          }
        }
        track.output.sampleMetadata(timeUs, flags, size, offset, track.cryptoData);
      }
      haveOutputSample = true;
    }
  
    /**
     * Ensures {@link #scratch} contains at least {@code requiredLength} bytes of data, reading from
     * the extractor input if necessary.
     */
    private void readScratch(ExtractorInput input, int requiredLength) throws IOException {
      if (scratch.limit() >= requiredLength) {
        return;
      }
      if (scratch.capacity() < requiredLength) {
        scratch.ensureCapacity(max(scratch.capacity() * 2, requiredLength));
      }
      input.readFully(scratch.getData(), scratch.limit(), requiredLength - scratch.limit());
      scratch.setLimit(requiredLength);
    }
  
    /**
     * Writes data for a single sample to the track output.
     *
     * @param input The input from which to read sample data.
     * @param track The track to output the sample to.
     * @param size The size of the sample data on the input side.
     * @param isBlockGroup Whether the samples are from a BlockGroup.
     * @return The final size of the written sample.
     * @throws IOException If an error occurs reading from the input.
     */
    @RequiresNonNull("#2.output")
    private int writeSampleData(ExtractorInput input, Track track, int size, boolean isBlockGroup)
        throws IOException {
      if (CODEC_ID_SUBRIP.equals(track.codecId)) {
        writeSubtitleSampleData(input, SUBRIP_PREFIX, size);
        return finishWriteSampleData();
      } else if (CODEC_ID_ASS.equals(track.codecId)) {
        writeSubtitleSampleData(input, SSA_PREFIX, size);
        return finishWriteSampleData();
      } else if (CODEC_ID_VTT.equals(track.codecId)) {
        writeSubtitleSampleData(input, VTT_PREFIX, size);
        return finishWriteSampleData();
      }
  
      TrackOutput output = track.output;
      if (!sampleEncodingHandled) {
        if (track.hasContentEncryption) {
          // If the sample is encrypted, read its encryption signal byte and set the IV size.
          // Clear the encrypted flag.
          blockFlags &= ~C.BUFFER_FLAG_ENCRYPTED;
          if (!sampleSignalByteRead) {
            input.readFully(scratch.getData(), 0, 1);
            sampleBytesRead++;
            if ((scratch.getData()[0] & 0x80) == 0x80) {
              throw ParserException.createForMalformedContainer(
                  "Extension bit is set in signal byte", /* cause= */ null);
            }
            sampleSignalByte = scratch.getData()[0];
            sampleSignalByteRead = true;
          }
          boolean isEncrypted = (sampleSignalByte & 0x01) == 0x01;
          if (isEncrypted) {
            boolean hasSubsampleEncryption = (sampleSignalByte & 0x02) == 0x02;
            blockFlags |= C.BUFFER_FLAG_ENCRYPTED;
            if (!sampleInitializationVectorRead) {
              input.readFully(encryptionInitializationVector.getData(), 0, ENCRYPTION_IV_SIZE);
              sampleBytesRead += ENCRYPTION_IV_SIZE;
              sampleInitializationVectorRead = true;
              // Write the signal byte, containing the IV size and the subsample encryption flag.
              scratch.getData()[0] =
                  (byte) (ENCRYPTION_IV_SIZE | (hasSubsampleEncryption ? 0x80 : 0x00));
              scratch.setPosition(0);
              output.sampleData(scratch, 1, TrackOutput.SAMPLE_DATA_PART_ENCRYPTION);
              sampleBytesWritten++;
              // Write the IV.
              encryptionInitializationVector.setPosition(0);
              output.sampleData(
                  encryptionInitializationVector,
                  ENCRYPTION_IV_SIZE,
                  TrackOutput.SAMPLE_DATA_PART_ENCRYPTION);
              sampleBytesWritten += ENCRYPTION_IV_SIZE;
            }
            if (hasSubsampleEncryption) {
              if (!samplePartitionCountRead) {
                input.readFully(scratch.getData(), 0, 1);
                sampleBytesRead++;
                scratch.setPosition(0);
                samplePartitionCount = scratch.readUnsignedByte();
                samplePartitionCountRead = true;
              }
              int samplePartitionDataSize = samplePartitionCount * 4;
              scratch.reset(samplePartitionDataSize);
              input.readFully(scratch.getData(), 0, samplePartitionDataSize);
              sampleBytesRead += samplePartitionDataSize;
              short subsampleCount = (short) (1 + (samplePartitionCount / 2));
              int subsampleDataSize = 2 + 6 * subsampleCount;
              if (encryptionSubsampleDataBuffer == null
                  || encryptionSubsampleDataBuffer.capacity() < subsampleDataSize) {
                encryptionSubsampleDataBuffer = ByteBuffer.allocate(subsampleDataSize);
              }
              encryptionSubsampleDataBuffer.position(0);
              encryptionSubsampleDataBuffer.putShort(subsampleCount);
              // Loop through the partition offsets and write out the data in the way ExoPlayer
              // wants it (ISO 23001-7 Part 7):
              //   2 bytes - sub sample count.
              //   for each sub sample:
              //     2 bytes - clear data size.
              //     4 bytes - encrypted data size.
              int partitionOffset = 0;
              for (int i = 0; i < samplePartitionCount; i++) {
                int previousPartitionOffset = partitionOffset;
                partitionOffset = scratch.readUnsignedIntToInt();
                if ((i % 2) == 0) {
                  encryptionSubsampleDataBuffer.putShort(
                      (short) (partitionOffset - previousPartitionOffset));
                } else {
                  encryptionSubsampleDataBuffer.putInt(partitionOffset - previousPartitionOffset);
                }
              }
              int finalPartitionSize = size - sampleBytesRead - partitionOffset;
              if ((samplePartitionCount % 2) == 1) {
                encryptionSubsampleDataBuffer.putInt(finalPartitionSize);
              } else {
                encryptionSubsampleDataBuffer.putShort((short) finalPartitionSize);
                encryptionSubsampleDataBuffer.putInt(0);
              }
              encryptionSubsampleData.reset(encryptionSubsampleDataBuffer.array(), subsampleDataSize);
              output.sampleData(
                  encryptionSubsampleData,
                  subsampleDataSize,
                  TrackOutput.SAMPLE_DATA_PART_ENCRYPTION);
              sampleBytesWritten += subsampleDataSize;
            }
          }
        } else if (track.sampleStrippedBytes != null) {
          // If the sample has header stripping, prepare to read/output the stripped bytes first.
          sampleStrippedBytes.reset(track.sampleStrippedBytes, track.sampleStrippedBytes.length);
        }
  
        if (track.samplesHaveSupplementalData(isBlockGroup)) {
          blockFlags |= C.BUFFER_FLAG_HAS_SUPPLEMENTAL_DATA;
          supplementalData.reset(/* limit= */ 0);
          // If there is supplemental data, the structure of the sample data is:
          // encryption data (if any) || sample size (4 bytes) || sample data || supplemental data
          int sampleSize = size + sampleStrippedBytes.limit() - sampleBytesRead;
          scratch.reset(/* limit= */ 4);
          scratch.getData()[0] = (byte) ((sampleSize >> 24) & 0xFF);
          scratch.getData()[1] = (byte) ((sampleSize >> 16) & 0xFF);
          scratch.getData()[2] = (byte) ((sampleSize >> 8) & 0xFF);
          scratch.getData()[3] = (byte) (sampleSize & 0xFF);
          output.sampleData(scratch, 4, TrackOutput.SAMPLE_DATA_PART_SUPPLEMENTAL);
          sampleBytesWritten += 4;
        }
  
        sampleEncodingHandled = true;
      }
      size += sampleStrippedBytes.limit();
  
      if (CODEC_ID_H264.equals(track.codecId) || CODEC_ID_H265.equals(track.codecId)) {
        // TODO: Deduplicate with Mp4Extractor.
  
        // Zero the top three bytes of the array that we'll use to decode nal unit lengths, in case
        // they're only 1 or 2 bytes long.
        byte[] nalLengthData = nalLength.getData();
        nalLengthData[0] = 0;
        nalLengthData[1] = 0;
        nalLengthData[2] = 0;
        int nalUnitLengthFieldLength = track.nalUnitLengthFieldLength;
        int nalUnitLengthFieldLengthDiff = 4 - track.nalUnitLengthFieldLength;
        // NAL units are length delimited, but the decoder requires start code delimited units.
        // Loop until we've written the sample to the track output, replacing length delimiters with
        // start codes as we encounter them.
        while (sampleBytesRead < size) {
          if (sampleCurrentNalBytesRemaining == 0) {
            // Read the NAL length so that we know where we find the next one.
            writeToTarget(
                input, nalLengthData, nalUnitLengthFieldLengthDiff, nalUnitLengthFieldLength);
            sampleBytesRead += nalUnitLengthFieldLength;
            nalLength.setPosition(0);
            sampleCurrentNalBytesRemaining = nalLength.readUnsignedIntToInt();
            // Write a start code for the current NAL unit.
            nalStartCode.setPosition(0);
            output.sampleData(nalStartCode, 4);
            sampleBytesWritten += 4;
          } else {
            // Write the payload of the NAL unit.
            int bytesWritten = writeToOutput(input, output, sampleCurrentNalBytesRemaining);
            sampleBytesRead += bytesWritten;
            sampleBytesWritten += bytesWritten;
            sampleCurrentNalBytesRemaining -= bytesWritten;
          }
        }
      } else {
        if (track.trueHdSampleRechunker != null) {
          checkState(sampleStrippedBytes.limit() == 0);
          track.trueHdSampleRechunker.startSample(input);
        }
        while (sampleBytesRead < size) {
          int bytesWritten = writeToOutput(input, output, size - sampleBytesRead);
          sampleBytesRead += bytesWritten;
          sampleBytesWritten += bytesWritten;
        }
      }
  
      if (CODEC_ID_VORBIS.equals(track.codecId)) {
        // Vorbis decoder in android MediaCodec [1] expects the last 4 bytes of the sample to be the
        // number of samples in the current page. This definition holds good only for Ogg and
        // irrelevant for Matroska. So we always set this to -1 (the decoder will ignore this value if
        // we set it to -1). The android platform media extractor [2] does the same.
        // [1]
        // https://android.googlesource.com/platform/frameworks/av/+/lollipop-release/media/libstagefright/codecs/vorbis/dec/SoftVorbis.cpp#314
        // [2]
        // https://android.googlesource.com/platform/frameworks/av/+/lollipop-release/media/libstagefright/NuMediaExtractor.cpp#474
        vorbisNumPageSamples.setPosition(0);
        output.sampleData(vorbisNumPageSamples, 4);
        sampleBytesWritten += 4;
      }
  
      return finishWriteSampleData();
    }
  
    /**
     * Called by {@link #writeSampleData(ExtractorInput, Track, int, boolean)} when the sample has
     * been written. Returns the final sample size and resets state for the next sample.
     */
    private int finishWriteSampleData() {
      int sampleSize = sampleBytesWritten;
      resetWriteSampleData();
      return sampleSize;
    }
  
    /** Resets state used by {@link #writeSampleData(ExtractorInput, Track, int, boolean)}. */
    private void resetWriteSampleData() {
      sampleBytesRead = 0;
      sampleBytesWritten = 0;
      sampleCurrentNalBytesRemaining = 0;
      sampleEncodingHandled = false;
      sampleSignalByteRead = false;
      samplePartitionCountRead = false;
      samplePartitionCount = 0;
      sampleSignalByte = (byte) 0;
      sampleInitializationVectorRead = false;
      sampleStrippedBytes.reset(/* limit= */ 0);
    }
  
    private void writeSubtitleSampleData(ExtractorInput input, byte[] samplePrefix, int size)
        throws IOException {
      int sizeWithPrefix = samplePrefix.length + size;
      if (subtitleSample.capacity() < sizeWithPrefix) {
        // Initialize subripSample to contain the required prefix and have space to hold a subtitle
        // twice as long as this one.
        subtitleSample.reset(Arrays.copyOf(samplePrefix, sizeWithPrefix + size));
      } else {
        System.arraycopy(samplePrefix, 0, subtitleSample.getData(), 0, samplePrefix.length);
      }
      input.readFully(subtitleSample.getData(), samplePrefix.length, size);
      subtitleSample.setPosition(0);
      subtitleSample.setLimit(sizeWithPrefix);
      // Defer writing the data to the track output. We need to modify the sample data by setting
      // the correct end timecode, which we might not have yet.
    }
  
    /**
     * Overwrites the end timecode in {@code subtitleData} with the correctly formatted time derived
     * from {@code durationUs}.
     *
     * <p>See documentation on {@link #SSA_DIALOGUE_FORMAT} and {@link #SUBRIP_PREFIX} for why we use
     * the duration as the end timecode.
     *
     * @param codecId The subtitle codec; must be {@link #CODEC_ID_SUBRIP}, {@link #CODEC_ID_ASS} or
     *     {@link #CODEC_ID_VTT}.
     * @param durationUs The duration of the sample, in microseconds.
     * @param subtitleData The subtitle sample in which to overwrite the end timecode (output
     *     parameter).
     */
    private static void setSubtitleEndTime(String codecId, long durationUs, byte[] subtitleData) {
      byte[] endTimecode;
      int endTimecodeOffset;
      switch (codecId) {
        case CODEC_ID_SUBRIP:
          endTimecode =
              formatSubtitleTimecode(
                  durationUs, SUBRIP_TIMECODE_FORMAT, SUBRIP_TIMECODE_LAST_VALUE_SCALING_FACTOR);
          endTimecodeOffset = SUBRIP_PREFIX_END_TIMECODE_OFFSET;
          break;
        case CODEC_ID_ASS:
          endTimecode =
              formatSubtitleTimecode(
                  durationUs, SSA_TIMECODE_FORMAT, SSA_TIMECODE_LAST_VALUE_SCALING_FACTOR);
          endTimecodeOffset = SSA_PREFIX_END_TIMECODE_OFFSET;
          break;
        case CODEC_ID_VTT:
          endTimecode =
              formatSubtitleTimecode(
                  durationUs, VTT_TIMECODE_FORMAT, VTT_TIMECODE_LAST_VALUE_SCALING_FACTOR);
          endTimecodeOffset = VTT_PREFIX_END_TIMECODE_OFFSET;
          break;
        default:
          throw new IllegalArgumentException();
      }
      System.arraycopy(endTimecode, 0, subtitleData, endTimecodeOffset, endTimecode.length);
    }
  
    /**
     * Formats {@code timeUs} using {@code timecodeFormat}, and sets it as the end timecode in {@code
     * subtitleSampleData}.
     */
    private static byte[] formatSubtitleTimecode(
        long timeUs, String timecodeFormat, long lastTimecodeValueScalingFactor) {
      checkArgument(timeUs != C.TIME_UNSET);
      byte[] timeCodeData;
      int hours = (int) (timeUs / (3600 * C.MICROS_PER_SECOND));
      timeUs -= (hours * 3600L * C.MICROS_PER_SECOND);
      int minutes = (int) (timeUs / (60 * C.MICROS_PER_SECOND));
      timeUs -= (minutes * 60L * C.MICROS_PER_SECOND);
      int seconds = (int) (timeUs / C.MICROS_PER_SECOND);
      timeUs -= (seconds * C.MICROS_PER_SECOND);
      int lastValue = (int) (timeUs / lastTimecodeValueScalingFactor);
      timeCodeData =
          Util.getUtf8Bytes(
              String.format(Locale.US, timecodeFormat, hours, minutes, seconds, lastValue));
      return timeCodeData;
    }
  
    /**
     * Writes {@code length} bytes of sample data into {@code target} at {@code offset}, consisting of
     * pending {@link #sampleStrippedBytes} and any remaining data read from {@code input}.
     */
    private void writeToTarget(ExtractorInput input, byte[] target, int offset, int length)
        throws IOException {
      int pendingStrippedBytes = min(length, sampleStrippedBytes.bytesLeft());
      input.readFully(target, offset + pendingStrippedBytes, length - pendingStrippedBytes);
      if (pendingStrippedBytes > 0) {
        sampleStrippedBytes.readBytes(target, offset, pendingStrippedBytes);
      }
    }
  
    /**
     * Outputs up to {@code length} bytes of sample data to {@code output}, consisting of either
     * {@link #sampleStrippedBytes} or data read from {@code input}.
     */
    private int writeToOutput(ExtractorInput input, TrackOutput output, int length)
        throws IOException {
      int bytesWritten;
      int strippedBytesLeft = sampleStrippedBytes.bytesLeft();
      if (strippedBytesLeft > 0) {
        bytesWritten = min(length, strippedBytesLeft);
        output.sampleData(sampleStrippedBytes, bytesWritten);
      } else {
        bytesWritten = output.sampleData(input, length, false);
      }
      return bytesWritten;
    }
  
    /**
     * Builds a {@link SeekMap} from the recently gathered Cues information.
     *
     * @return The built {@link SeekMap}. The returned {@link SeekMap} may be unseekable if cues
     *     information was missing or incomplete.
     */
    private SeekMap buildSeekMap(
        @Nullable LongArray cueTimesUs, @Nullable LongArray cueClusterPositions) {
      if (segmentContentPosition == C.POSITION_UNSET
          || durationUs == C.TIME_UNSET
          || cueTimesUs == null
          || cueTimesUs.size() == 0
          || cueClusterPositions == null
          || cueClusterPositions.size() != cueTimesUs.size()) {
        // Cues information is missing or incomplete.
        return new SeekMap.Unseekable(durationUs);
      }
      int cuePointsSize = cueTimesUs.size();
      int[] sizes = new int[cuePointsSize];
      long[] offsets = new long[cuePointsSize];
      long[] durationsUs = new long[cuePointsSize];
      long[] timesUs = new long[cuePointsSize];
      for (int i = 0; i < cuePointsSize; i++) {
        timesUs[i] = cueTimesUs.get(i);
        offsets[i] = segmentContentPosition + cueClusterPositions.get(i);
      }
      for (int i = 0; i < cuePointsSize - 1; i++) {
        sizes[i] = (int) (offsets[i + 1] - offsets[i]);
        durationsUs[i] = timesUs[i + 1] - timesUs[i];
      }
      sizes[cuePointsSize - 1] =
          (int) (segmentContentPosition + segmentContentSize - offsets[cuePointsSize - 1]);
      durationsUs[cuePointsSize - 1] = durationUs - timesUs[cuePointsSize - 1];
  
      long lastDurationUs = durationsUs[cuePointsSize - 1];
      if (lastDurationUs <= 0) {
        Log.w(TAG, "Discarding last cue point with unexpected duration: " + lastDurationUs);
        sizes = Arrays.copyOf(sizes, sizes.length - 1);
        offsets = Arrays.copyOf(offsets, offsets.length - 1);
        durationsUs = Arrays.copyOf(durationsUs, durationsUs.length - 1);
        timesUs = Arrays.copyOf(timesUs, timesUs.length - 1);
      }
  
      return new ChunkIndex(sizes, offsets, durationsUs, timesUs);
    }
  
    /**
     * Updates the position of the holder to Cues element's position if the extractor configuration
     * permits use of master seek entry. After building Cues sets the holder's position back to where
     * it was before.
     *
     * @param seekPosition The holder whose position will be updated.
     * @param currentPosition Current position of the input.
     * @return Whether the seek position was updated.
     */
    private boolean maybeSeekForCues(PositionHolder seekPosition, long currentPosition) {
      if (seekForCues) {
        seekPositionAfterBuildingCues = currentPosition;
        seekPosition.position = cuesContentPosition;
        seekForCues = false;
        return true;
      }
      // After parsing Cues, seek back to original position if available. We will not do this unless
      // we seeked to get to the Cues in the first place.
      if (sentSeekMap && seekPositionAfterBuildingCues != C.POSITION_UNSET) {
        seekPosition.position = seekPositionAfterBuildingCues;
        seekPositionAfterBuildingCues = C.POSITION_UNSET;
        return true;
      }
      return false;
    }
  
    private long scaleTimecodeToUs(long unscaledTimecode) throws ParserException {
      if (timecodeScale == C.TIME_UNSET) {
        throw ParserException.createForMalformedContainer(
            "Can't scale timecode prior to timecodeScale being set.", /* cause= */ null);
      }
      return Util.scaleLargeTimestamp(unscaledTimecode, timecodeScale, 1000);
    }
  
    private static boolean isCodecSupported(String codecId) {
      switch (codecId) {
        case CODEC_ID_VP8:
        case CODEC_ID_VP9:
        case CODEC_ID_AV1:
        case CODEC_ID_MPEG2:
        case CODEC_ID_MPEG4_SP:
        case CODEC_ID_MPEG4_ASP:
        case CODEC_ID_MPEG4_AP:
        case CODEC_ID_H264:
        case CODEC_ID_H265:
        case CODEC_ID_FOURCC:
        case CODEC_ID_THEORA:
        case CODEC_ID_OPUS:
        case CODEC_ID_VORBIS:
        case CODEC_ID_AAC:
        case CODEC_ID_MP2:
        case CODEC_ID_MP3:
        case CODEC_ID_AC3:
        case CODEC_ID_E_AC3:
        case CODEC_ID_TRUEHD:
        case CODEC_ID_DTS:
        case CODEC_ID_DTS_EXPRESS:
        case CODEC_ID_DTS_LOSSLESS:
        case CODEC_ID_FLAC:
        case CODEC_ID_ACM:
        case CODEC_ID_PCM_INT_LIT:
        case CODEC_ID_PCM_INT_BIG:
        case CODEC_ID_PCM_FLOAT:
        case CODEC_ID_SUBRIP:
        case CODEC_ID_ASS:
        case CODEC_ID_VTT:
        case CODEC_ID_VOBSUB:
        case CODEC_ID_PGS:
        case CODEC_ID_DVBSUB:
          return true;
        default:
          return false;
      }
    }
  
    /**
     * Returns an array that can store (at least) {@code length} elements, which will be either a new
     * array or {@code array} if it's not null and large enough.
     */
    private static int[] ensureArrayCapacity(@Nullable int[] array, int length) {
      if (array == null) {
        return new int[length];
      } else if (array.length >= length) {
        return array;
      } else {
        // Double the size to avoid allocating constantly if the required length increases gradually.
        return new int[max(array.length * 2, length)];
      }
    }
  
    @EnsuresNonNull("extractorOutput")
    private void assertInitialized() {
      checkStateNotNull(extractorOutput);
    }
  
    /** Passes events through to the outer {@link MatroskaExtractor}. */
    private final class InnerEbmlProcessor implements EbmlProcessor {
  
      @Override
      public @ElementType int getElementType(int id) {
        return MatroskaExtractor.this.getElementType(id);
      }
  
      @Override
      public boolean isLevel1Element(int id) {
        return MatroskaExtractor.this.isLevel1Element(id);
      }
  
      @Override
      public void startMasterElement(int id, long contentPosition, long contentSize)
          throws ParserException {
        MatroskaExtractor.this.startMasterElement(id, contentPosition, contentSize);
      }
  
      @Override
      public void endMasterElement(int id) throws ParserException {
        MatroskaExtractor.this.endMasterElement(id);
      }
  
      @Override
      public void integerElement(int id, long value) throws ParserException {
        MatroskaExtractor.this.integerElement(id, value);
      }
  
      @Override
      public void floatElement(int id, double value) throws ParserException {
        MatroskaExtractor.this.floatElement(id, value);
      }
  
      @Override
      public void stringElement(int id, String value) throws ParserException {
        MatroskaExtractor.this.stringElement(id, value);
      }
  
      @Override
      public void binaryElement(int id, int contentsSize, ExtractorInput input) throws IOException {
        MatroskaExtractor.this.binaryElement(id, contentsSize, input);
      }
    }
  
    /** Holds data corresponding to a single track. */
    protected static final class Track {
  
      private static final int DISPLAY_UNIT_PIXELS = 0;
      private static final int MAX_CHROMATICITY = 50_000; // Defined in CTA-861.3.
      /** Default max content light level (CLL) that should be encoded into hdrStaticInfo. */
      private static final int DEFAULT_MAX_CLL = 1000; // nits.
  
      /** Default frame-average light level (FALL) that should be encoded into hdrStaticInfo. */
      private static final int DEFAULT_MAX_FALL = 200; // nits.
  
      // Common elements.
      public @MonotonicNonNull String name;
      public @MonotonicNonNull String codecId;
      public int number;
      public int type;
      public int defaultSampleDurationNs;
      public int maxBlockAdditionId;
      private int blockAddIdType;
      public boolean hasContentEncryption;
      public byte @MonotonicNonNull [] sampleStrippedBytes;
      public TrackOutput.@MonotonicNonNull CryptoData cryptoData;
      public byte @MonotonicNonNull [] codecPrivate;
      public @MonotonicNonNull DrmInitData drmInitData;
  
      // Video elements.
      public int width = Format.NO_VALUE;
      public int height = Format.NO_VALUE;
      public int displayWidth = Format.NO_VALUE;
      public int displayHeight = Format.NO_VALUE;
      public int displayUnit = DISPLAY_UNIT_PIXELS;
      public @C.Projection int projectionType = Format.NO_VALUE;
      public float projectionPoseYaw = 0f;
      public float projectionPosePitch = 0f;
      public float projectionPoseRoll = 0f;
      public byte @MonotonicNonNull [] projectionData = null;
      public @C.StereoMode int stereoMode = Format.NO_VALUE;
      public boolean hasColorInfo = false;
      public @C.ColorSpace int colorSpace = Format.NO_VALUE;
      public @C.ColorTransfer int colorTransfer = Format.NO_VALUE;
      public @C.ColorRange int colorRange = Format.NO_VALUE;
      public int maxContentLuminance = DEFAULT_MAX_CLL;
      public int maxFrameAverageLuminance = DEFAULT_MAX_FALL;
      public float primaryRChromaticityX = Format.NO_VALUE;
      public float primaryRChromaticityY = Format.NO_VALUE;
      public float primaryGChromaticityX = Format.NO_VALUE;
      public float primaryGChromaticityY = Format.NO_VALUE;
      public float primaryBChromaticityX = Format.NO_VALUE;
      public float primaryBChromaticityY = Format.NO_VALUE;
      public float whitePointChromaticityX = Format.NO_VALUE;
      public float whitePointChromaticityY = Format.NO_VALUE;
      public float maxMasteringLuminance = Format.NO_VALUE;
      public float minMasteringLuminance = Format.NO_VALUE;
      public byte @MonotonicNonNull [] dolbyVisionConfigBytes;
  
      // Audio elements. Initially set to their default values.
      public int channelCount = 1;
      public int audioBitDepth = Format.NO_VALUE;
      public int sampleRate = 8000;
      public long codecDelayNs = 0;
      public long seekPreRollNs = 0;
      public @MonotonicNonNull TrueHdSampleRechunker trueHdSampleRechunker;
  
      // Text elements.
      public boolean flagForced;
      public boolean flagDefault = true;
      private String language = "eng";
  
      // Set when the output is initialized. nalUnitLengthFieldLength is only set for H264/H265.
      public @MonotonicNonNull TrackOutput output;
      public int nalUnitLengthFieldLength;
  
      /** Initializes the track with an output. */
      @RequiresNonNull("codecId")
      @EnsuresNonNull("this.output")
      public void initializeOutput(ExtractorOutput output, int trackId) throws ParserException {
        String mimeType;
        int maxInputSize = Format.NO_VALUE;
        @C.PcmEncoding int pcmEncoding = Format.NO_VALUE;
        @Nullable List<byte[]> initializationData = null;
        @Nullable String codecs = null;
        switch (codecId) {
          case CODEC_ID_VP8:
            mimeType = MimeTypes.VIDEO_VP8;
            break;
          case CODEC_ID_VP9:
            mimeType = MimeTypes.VIDEO_VP9;
            break;
          case CODEC_ID_AV1:
            mimeType = MimeTypes.VIDEO_AV1;
            break;
          case CODEC_ID_MPEG2:
            mimeType = MimeTypes.VIDEO_MPEG2;
            break;
          case CODEC_ID_MPEG4_SP:
          case CODEC_ID_MPEG4_ASP:
          case CODEC_ID_MPEG4_AP:
            mimeType = MimeTypes.VIDEO_MP4V;
            initializationData =
                codecPrivate == null ? null : Collections.singletonList(codecPrivate);
            break;
          case CODEC_ID_H264:
            mimeType = MimeTypes.VIDEO_H264;
            AvcConfig avcConfig = AvcConfig.parse(new ParsableByteArray(getCodecPrivate(codecId)));
            initializationData = avcConfig.initializationData;
            nalUnitLengthFieldLength = avcConfig.nalUnitLengthFieldLength;
            codecs = avcConfig.codecs;
            break;
          case CODEC_ID_H265:
            mimeType = MimeTypes.VIDEO_H265;
            HevcConfig hevcConfig = HevcConfig.parse(new ParsableByteArray(getCodecPrivate(codecId)));
            initializationData = hevcConfig.initializationData;
            nalUnitLengthFieldLength = hevcConfig.nalUnitLengthFieldLength;
            codecs = hevcConfig.codecs;
            break;
          case CODEC_ID_FOURCC:
            Pair<String, @NullableType List<byte[]>> pair =
                parseFourCcPrivate(new ParsableByteArray(getCodecPrivate(codecId)));
            mimeType = pair.first;
            initializationData = pair.second;
            break;
          case CODEC_ID_THEORA:
            // TODO: This can be set to the real mimeType if/when we work out what initializationData
            // should be set to for this case.
            mimeType = MimeTypes.VIDEO_UNKNOWN;
            break;
          case CODEC_ID_VORBIS:
            mimeType = MimeTypes.AUDIO_VORBIS;
            maxInputSize = VORBIS_MAX_INPUT_SIZE;
            initializationData = parseVorbisCodecPrivate(getCodecPrivate(codecId));
            break;
          case CODEC_ID_OPUS:
            mimeType = MimeTypes.AUDIO_OPUS;
            maxInputSize = OPUS_MAX_INPUT_SIZE;
            initializationData = new ArrayList<>(3);
            initializationData.add(getCodecPrivate(codecId));
            initializationData.add(
                ByteBuffer.allocate(8).order(ByteOrder.LITTLE_ENDIAN).putLong(codecDelayNs).array());
            initializationData.add(
                ByteBuffer.allocate(8).order(ByteOrder.LITTLE_ENDIAN).putLong(seekPreRollNs).array());
            break;
          case CODEC_ID_AAC:
            mimeType = MimeTypes.AUDIO_AAC;
            initializationData = Collections.singletonList(getCodecPrivate(codecId));
            AacUtil.Config aacConfig = AacUtil.parseAudioSpecificConfig(codecPrivate);
            // Update sampleRate and channelCount from the AudioSpecificConfig initialization data,
            // which is more reliable. See [Internal: b/10903778].
            sampleRate = aacConfig.sampleRateHz;
            channelCount = aacConfig.channelCount;
            codecs = aacConfig.codecs;
            break;
          case CODEC_ID_MP2:
            mimeType = MimeTypes.AUDIO_MPEG_L2;
            maxInputSize = MpegAudioUtil.MAX_FRAME_SIZE_BYTES;
            break;
          case CODEC_ID_MP3:
            mimeType = MimeTypes.AUDIO_MPEG;
            maxInputSize = MpegAudioUtil.MAX_FRAME_SIZE_BYTES;
            break;
          case CODEC_ID_AC3:
            mimeType = MimeTypes.AUDIO_AC3;
            break;
          case CODEC_ID_E_AC3:
            mimeType = MimeTypes.AUDIO_E_AC3;
            break;
          case CODEC_ID_TRUEHD:
            mimeType = MimeTypes.AUDIO_TRUEHD;
            trueHdSampleRechunker = new TrueHdSampleRechunker();
            break;
          case CODEC_ID_DTS:
          case CODEC_ID_DTS_EXPRESS:
            mimeType = MimeTypes.AUDIO_DTS;
            break;
          case CODEC_ID_DTS_LOSSLESS:
            mimeType = MimeTypes.AUDIO_DTS_HD;
            break;
          case CODEC_ID_FLAC:
            mimeType = MimeTypes.AUDIO_FLAC;
            initializationData = Collections.singletonList(getCodecPrivate(codecId));
            break;
          case CODEC_ID_ACM:
            mimeType = MimeTypes.AUDIO_RAW;
            if (parseMsAcmCodecPrivate(new ParsableByteArray(getCodecPrivate(codecId)))) {
              pcmEncoding = Util.getPcmEncoding(audioBitDepth);
              if (pcmEncoding == C.ENCODING_INVALID) {
                pcmEncoding = Format.NO_VALUE;
                mimeType = MimeTypes.AUDIO_UNKNOWN;
                Log.w(
                    TAG,
                    "Unsupported PCM bit depth: "
                        + audioBitDepth
                        + ". Setting mimeType to "
                        + mimeType);
              }
            } else {
              mimeType = MimeTypes.AUDIO_UNKNOWN;
              Log.w(TAG, "Non-PCM MS/ACM is unsupported. Setting mimeType to " + mimeType);
            }
            break;
          case CODEC_ID_PCM_INT_LIT:
            mimeType = MimeTypes.AUDIO_RAW;
            pcmEncoding = Util.getPcmEncoding(audioBitDepth);
            if (pcmEncoding == C.ENCODING_INVALID) {
              pcmEncoding = Format.NO_VALUE;
              mimeType = MimeTypes.AUDIO_UNKNOWN;
              Log.w(
                  TAG,
                  "Unsupported little endian PCM bit depth: "
                      + audioBitDepth
                      + ". Setting mimeType to "
                      + mimeType);
            }
            break;
          case CODEC_ID_PCM_INT_BIG:
            mimeType = MimeTypes.AUDIO_RAW;
            if (audioBitDepth == 8) {
              pcmEncoding = C.ENCODING_PCM_8BIT;
            } else if (audioBitDepth == 16) {
              pcmEncoding = C.ENCODING_PCM_16BIT_BIG_ENDIAN;
            } else {
              pcmEncoding = Format.NO_VALUE;
              mimeType = MimeTypes.AUDIO_UNKNOWN;
              Log.w(
                  TAG,
                  "Unsupported big endian PCM bit depth: "
                      + audioBitDepth
                      + ". Setting mimeType to "
                      + mimeType);
            }
            break;
          case CODEC_ID_PCM_FLOAT:
            mimeType = MimeTypes.AUDIO_RAW;
            if (audioBitDepth == 32) {
              pcmEncoding = C.ENCODING_PCM_FLOAT;
            } else {
              pcmEncoding = Format.NO_VALUE;
              mimeType = MimeTypes.AUDIO_UNKNOWN;
              Log.w(
                  TAG,
                  "Unsupported floating point PCM bit depth: "
                      + audioBitDepth
                      + ". Setting mimeType to "
                      + mimeType);
            }
            break;
          case CODEC_ID_SUBRIP:
            mimeType = MimeTypes.APPLICATION_SUBRIP;
            break;
          case CODEC_ID_ASS:
            mimeType = MimeTypes.TEXT_SSA;
            initializationData = ImmutableList.of(SSA_DIALOGUE_FORMAT, getCodecPrivate(codecId));
            break;
          case CODEC_ID_VTT:
            mimeType = MimeTypes.TEXT_VTT;
            break;
          case CODEC_ID_VOBSUB:
            mimeType = MimeTypes.APPLICATION_VOBSUB;
            initializationData = ImmutableList.of(getCodecPrivate(codecId));
            break;
          case CODEC_ID_PGS:
            mimeType = MimeTypes.APPLICATION_PGS;
            break;
          case CODEC_ID_DVBSUB:
            mimeType = MimeTypes.APPLICATION_DVBSUBS;
            // Init data: composition_page (2), ancillary_page (2)
            byte[] initializationDataBytes = new byte[4];
            System.arraycopy(getCodecPrivate(codecId), 0, initializationDataBytes, 0, 4);
            initializationData = ImmutableList.of(initializationDataBytes);
            break;
          default:
            throw ParserException.createForMalformedContainer(
                "Unrecognized codec identifier.", /* cause= */ null);
        }
  
        if (dolbyVisionConfigBytes != null) {
          @Nullable
          DolbyVisionConfig dolbyVisionConfig =
              DolbyVisionConfig.parse(new ParsableByteArray(this.dolbyVisionConfigBytes));
          if (dolbyVisionConfig != null) {
            codecs = dolbyVisionConfig.codecs;
            mimeType = MimeTypes.VIDEO_DOLBY_VISION;
          }
        }
  
        @C.SelectionFlags int selectionFlags = 0;
        selectionFlags |= flagDefault ? C.SELECTION_FLAG_DEFAULT : 0;
        selectionFlags |= flagForced ? C.SELECTION_FLAG_FORCED : 0;
  
        int type;
        Format.Builder formatBuilder = new Format.Builder();
        // TODO: Consider reading the name elements of the tracks and, if present, incorporating them
        // into the trackId passed when creating the formats.
        if (MimeTypes.isAudio(mimeType)) {
          type = C.TRACK_TYPE_AUDIO;
          formatBuilder
              .setChannelCount(channelCount)
              .setSampleRate(sampleRate)
              .setPcmEncoding(pcmEncoding);
        } else if (MimeTypes.isVideo(mimeType)) {
          type = C.TRACK_TYPE_VIDEO;
          if (displayUnit == Track.DISPLAY_UNIT_PIXELS) {
            displayWidth = displayWidth == Format.NO_VALUE ? width : displayWidth;
            displayHeight = displayHeight == Format.NO_VALUE ? height : displayHeight;
          }
          float pixelWidthHeightRatio = Format.NO_VALUE;
          if (displayWidth != Format.NO_VALUE && displayHeight != Format.NO_VALUE) {
            pixelWidthHeightRatio = ((float) (height * displayWidth)) / (width * displayHeight);
          }
          @Nullable ColorInfo colorInfo = null;
          if (hasColorInfo) {
            @Nullable byte[] hdrStaticInfo = getHdrStaticInfo();
            colorInfo = new ColorInfo(colorSpace, colorRange, colorTransfer, hdrStaticInfo);
          }
          int rotationDegrees = Format.NO_VALUE;
  
          if (name != null && TRACK_NAME_TO_ROTATION_DEGREES.containsKey(name)) {
            rotationDegrees = TRACK_NAME_TO_ROTATION_DEGREES.get(name);
          }
          if (projectionType == C.PROJECTION_RECTANGULAR
              && Float.compare(projectionPoseYaw, 0f) == 0
              && Float.compare(projectionPosePitch, 0f) == 0) {
            // The range of projectionPoseRoll is [-180, 180].
            if (Float.compare(projectionPoseRoll, 0f) == 0) {
              rotationDegrees = 0;
            } else if (Float.compare(projectionPosePitch, 90f) == 0) {
              rotationDegrees = 90;
            } else if (Float.compare(projectionPosePitch, -180f) == 0
                || Float.compare(projectionPosePitch, 180f) == 0) {
              rotationDegrees = 180;
            } else if (Float.compare(projectionPosePitch, -90f) == 0) {
              rotationDegrees = 270;
            }
          }
          formatBuilder
              .setWidth(width)
              .setHeight(height)
              .setPixelWidthHeightRatio(pixelWidthHeightRatio)
              .setRotationDegrees(rotationDegrees)
              .setProjectionData(projectionData)
              .setStereoMode(stereoMode)
              .setColorInfo(colorInfo);
        } else if (MimeTypes.APPLICATION_SUBRIP.equals(mimeType)
            || MimeTypes.TEXT_SSA.equals(mimeType)
            || MimeTypes.TEXT_VTT.equals(mimeType)
            || MimeTypes.APPLICATION_VOBSUB.equals(mimeType)
            || MimeTypes.APPLICATION_PGS.equals(mimeType)
            || MimeTypes.APPLICATION_DVBSUBS.equals(mimeType)) {
          type = C.TRACK_TYPE_TEXT;
        } else {
          throw ParserException.createForMalformedContainer(
              "Unexpected MIME type.", /* cause= */ null);
        }
  
        if (name != null && !TRACK_NAME_TO_ROTATION_DEGREES.containsKey(name)) {
          formatBuilder.setLabel(name);
        }
  
        Format format =
            formatBuilder
                .setId(trackId)
                .setSampleMimeType(mimeType)
                .setMaxInputSize(maxInputSize)
                .setLanguage(language)
                .setSelectionFlags(selectionFlags)
                .setInitializationData(initializationData)
                .setCodecs(codecs)
                .setDrmInitData(drmInitData)
                .build();
  
        this.output = output.track(number, type);
        this.output.format(format);
      }
  
      /** Forces any pending sample metadata to be flushed to the output. */
      @RequiresNonNull("output")
      public void outputPendingSampleMetadata() {
        if (trueHdSampleRechunker != null) {
          trueHdSampleRechunker.outputPendingSampleMetadata(output, cryptoData);
        }
      }
  
      /** Resets any state stored in the track in response to a seek. */
      public void reset() {
        if (trueHdSampleRechunker != null) {
          trueHdSampleRechunker.reset();
        }
      }
  
      /**
       * Returns true if supplemental data will be attached to the samples.
       *
       * @param isBlockGroup Whether the samples are from a BlockGroup.
       */
      private boolean samplesHaveSupplementalData(boolean isBlockGroup) {
        if (CODEC_ID_OPUS.equals(codecId)) {
          // At the end of a BlockGroup, a positive DiscardPadding value will be written out as
          // supplemental data for Opus codec. Otherwise (i.e. DiscardPadding <= 0) supplemental data
          // size will be 0.
          return isBlockGroup;
        }
        return maxBlockAdditionId > 0;
      }
  
      /** Returns the HDR Static Info as defined in CTA-861.3. */
      @Nullable
      private byte[] getHdrStaticInfo() {
        // Are all fields present.
        if (primaryRChromaticityX == Format.NO_VALUE
            || primaryRChromaticityY == Format.NO_VALUE
            || primaryGChromaticityX == Format.NO_VALUE
            || primaryGChromaticityY == Format.NO_VALUE
            || primaryBChromaticityX == Format.NO_VALUE
            || primaryBChromaticityY == Format.NO_VALUE
            || whitePointChromaticityX == Format.NO_VALUE
            || whitePointChromaticityY == Format.NO_VALUE
            || maxMasteringLuminance == Format.NO_VALUE
            || minMasteringLuminance == Format.NO_VALUE) {
          return null;
        }
  
        byte[] hdrStaticInfoData = new byte[25];
        ByteBuffer hdrStaticInfo = ByteBuffer.wrap(hdrStaticInfoData).order(ByteOrder.LITTLE_ENDIAN);
        hdrStaticInfo.put((byte) 0); // Type.
        hdrStaticInfo.putShort((short) ((primaryRChromaticityX * MAX_CHROMATICITY) + 0.5f));
        hdrStaticInfo.putShort((short) ((primaryRChromaticityY * MAX_CHROMATICITY) + 0.5f));
        hdrStaticInfo.putShort((short) ((primaryGChromaticityX * MAX_CHROMATICITY) + 0.5f));
        hdrStaticInfo.putShort((short) ((primaryGChromaticityY * MAX_CHROMATICITY) + 0.5f));
        hdrStaticInfo.putShort((short) ((primaryBChromaticityX * MAX_CHROMATICITY) + 0.5f));
        hdrStaticInfo.putShort((short) ((primaryBChromaticityY * MAX_CHROMATICITY) + 0.5f));
        hdrStaticInfo.putShort((short) ((whitePointChromaticityX * MAX_CHROMATICITY) + 0.5f));
        hdrStaticInfo.putShort((short) ((whitePointChromaticityY * MAX_CHROMATICITY) + 0.5f));
        hdrStaticInfo.putShort((short) (maxMasteringLuminance + 0.5f));
        hdrStaticInfo.putShort((short) (minMasteringLuminance + 0.5f));
        hdrStaticInfo.putShort((short) maxContentLuminance);
        hdrStaticInfo.putShort((short) maxFrameAverageLuminance);
        return hdrStaticInfoData;
      }
  
      /**
       * Builds initialization data for a {@link Format} from FourCC codec private data.
       *
       * @return The codec mime type and initialization data. If the compression type is not supported
       *     then the mime type is set to {@link MimeTypes#VIDEO_UNKNOWN} and the initialization data
       *     is {@code null}.
       * @throws ParserException If the initialization data could not be built.
       */
      private static Pair<String, @NullableType List<byte[]>> parseFourCcPrivate(
          ParsableByteArray buffer) throws ParserException {
        try {
          buffer.skipBytes(16); // size(4), width(4), height(4), planes(2), bitcount(2).
          long compression = buffer.readLittleEndianUnsignedInt();
          if (compression == FOURCC_COMPRESSION_DIVX) {
            return new Pair<>(MimeTypes.VIDEO_DIVX, null);
          } else if (compression == FOURCC_COMPRESSION_H263) {
            return new Pair<>(MimeTypes.VIDEO_H263, null);
          } else if (compression == FOURCC_COMPRESSION_VC1) {
            // Search for the initialization data from the end of the BITMAPINFOHEADER. The last 20
            // bytes of which are: sizeImage(4), xPel/m (4), yPel/m (4), clrUsed(4), clrImportant(4).
            int startOffset = buffer.getPosition() + 20;
            byte[] bufferData = buffer.getData();
            for (int offset = startOffset; offset < bufferData.length - 4; offset++) {
              if (bufferData[offset] == 0x00
                  && bufferData[offset + 1] == 0x00
                  && bufferData[offset + 2] == 0x01
                  && bufferData[offset + 3] == 0x0F) {
                // We've found the initialization data.
                byte[] initializationData = Arrays.copyOfRange(bufferData, offset, bufferData.length);
                return new Pair<>(MimeTypes.VIDEO_VC1, Collections.singletonList(initializationData));
              }
            }
            throw ParserException.createForMalformedContainer(
                "Failed to find FourCC VC1 initialization data", /* cause= */ null);
          }
        } catch (ArrayIndexOutOfBoundsException e) {
          throw ParserException.createForMalformedContainer(
              "Error parsing FourCC private data", /* cause= */ null);
        }
  
        Log.w(TAG, "Unknown FourCC. Setting mimeType to " + MimeTypes.VIDEO_UNKNOWN);
        return new Pair<>(MimeTypes.VIDEO_UNKNOWN, null);
      }
  
      /**
       * Builds initialization data for a {@link Format} from Vorbis codec private data.
       *
       * @return The initialization data for the {@link Format}.
       * @throws ParserException If the initialization data could not be built.
       */
      private static List<byte[]> parseVorbisCodecPrivate(byte[] codecPrivate)
          throws ParserException {
        try {
          if (codecPrivate[0] != 0x02) {
            throw ParserException.createForMalformedContainer(
                "Error parsing vorbis codec private", /* cause= */ null);
          }
          int offset = 1;
          int vorbisInfoLength = 0;
          while ((codecPrivate[offset] & 0xFF) == 0xFF) {
            vorbisInfoLength += 0xFF;
            offset++;
          }
          vorbisInfoLength += codecPrivate[offset++] & 0xFF;
  
          int vorbisSkipLength = 0;
          while ((codecPrivate[offset] & 0xFF) == 0xFF) {
            vorbisSkipLength += 0xFF;
            offset++;
          }
          vorbisSkipLength += codecPrivate[offset++] & 0xFF;
  
          if (codecPrivate[offset] != 0x01) {
            throw ParserException.createForMalformedContainer(
                "Error parsing vorbis codec private", /* cause= */ null);
          }
          byte[] vorbisInfo = new byte[vorbisInfoLength];
          System.arraycopy(codecPrivate, offset, vorbisInfo, 0, vorbisInfoLength);
          offset += vorbisInfoLength;
          if (codecPrivate[offset] != 0x03) {
            throw ParserException.createForMalformedContainer(
                "Error parsing vorbis codec private", /* cause= */ null);
          }
          offset += vorbisSkipLength;
          if (codecPrivate[offset] != 0x05) {
            throw ParserException.createForMalformedContainer(
                "Error parsing vorbis codec private", /* cause= */ null);
          }
          byte[] vorbisBooks = new byte[codecPrivate.length - offset];
          System.arraycopy(codecPrivate, offset, vorbisBooks, 0, codecPrivate.length - offset);
          List<byte[]> initializationData = new ArrayList<>(2);
          initializationData.add(vorbisInfo);
          initializationData.add(vorbisBooks);
          return initializationData;
        } catch (ArrayIndexOutOfBoundsException e) {
          throw ParserException.createForMalformedContainer(
              "Error parsing vorbis codec private", /* cause= */ null);
        }
      }
  
      /**
       * Parses an MS/ACM codec private, returning whether it indicates PCM audio.
       *
       * @return Whether the codec private indicates PCM audio.
       * @throws ParserException If a parsing error occurs.
       */
      private static boolean parseMsAcmCodecPrivate(ParsableByteArray buffer) throws ParserException {
        try {
          int formatTag = buffer.readLittleEndianUnsignedShort();
          if (formatTag == WAVE_FORMAT_PCM) {
            return true;
          } else if (formatTag == WAVE_FORMAT_EXTENSIBLE) {
            buffer.setPosition(WAVE_FORMAT_SIZE + 6); // unionSamples(2), channelMask(4)
            return buffer.readLong() == WAVE_SUBFORMAT_PCM.getMostSignificantBits()
                && buffer.readLong() == WAVE_SUBFORMAT_PCM.getLeastSignificantBits();
          } else {
            return false;
          }
        } catch (ArrayIndexOutOfBoundsException e) {
          throw ParserException.createForMalformedContainer(
              "Error parsing MS/ACM codec private", /* cause= */ null);
        }
      }
  
      /**
       * Checks that the track has an output.
       *
       * <p>It is unfortunately not possible to mark {@link MatroskaExtractor#tracks} as only
       * containing tracks with output with the nullness checker. This method is used to check that
       * fact at runtime.
       */
      @EnsuresNonNull("output")
      private void assertOutputInitialized() {
        checkNotNull(output);
      }
  
      @EnsuresNonNull("codecPrivate")
      private byte[] getCodecPrivate(String codecId) throws ParserException {
        if (codecPrivate == null) {
          throw ParserException.createForMalformedContainer(
              "Missing CodecPrivate for codec " + codecId, /* cause= */ null);
        }
        return codecPrivate;
      }
    }
  }
  