public class

MatroskaExtractor

extends java.lang.Object

implements Extractor

 java.lang.Object

↳androidx.media3.extractor.mkv.MatroskaExtractor

Gradle dependencies

compile group: 'androidx.media3', name: 'media3-extractor', version: '1.5.0-alpha01'

  • groupId: androidx.media3
  • artifactId: media3-extractor
  • version: 1.5.0-alpha01

Artifact androidx.media3:media3-extractor:1.5.0-alpha01 it located at Google repository (https://maven.google.com/)

Overview

Extracts data from the Matroska and WebM container formats.

Summary

Fields
public static final ExtractorsFactoryFACTORY

public static final intFLAG_DISABLE_SEEK_FOR_CUES

Flag to disable seeking for cues.

public static final intFLAG_EMIT_RAW_SUBTITLE_DATA

Flag to use the source subtitle formats without modification.

Constructors
publicMatroskaExtractor()

publicMatroskaExtractor(int flags)

publicMatroskaExtractor(SubtitleParser.Factory subtitleParserFactory)

Constructs an instance.

publicMatroskaExtractor(SubtitleParser.Factory subtitleParserFactory, int flags)

Constructs an instance.

Methods
protected voidbinaryElement(int id, int contentSize, ExtractorInput input)

Called when a binary element is encountered.

protected voidendMasterElement(int id)

Called when the end of a master element is encountered.

protected voidfloatElement(int id, double value)

Called when a float element is encountered.

protected MatroskaExtractor.TrackgetCurrentTrack(int currentElementId)

Returns the track corresponding to the current TrackEntry element.

protected intgetElementType(int id)

Maps an element ID to a corresponding type.

protected voidhandleBlockAddIDExtraData(MatroskaExtractor.Track track, ExtractorInput input, int contentSize)

protected voidhandleBlockAdditionalData(MatroskaExtractor.Track track, int blockAdditionalId, ExtractorInput input, int contentSize)

public final voidinit(ExtractorOutput output)

protected voidintegerElement(int id, long value)

Called when an integer element is encountered.

protected booleanisLevel1Element(int id)

Checks if the given id is that of a level 1 element.

public static ExtractorsFactorynewFactory(SubtitleParser.Factory subtitleParserFactory)

Creates a factory for MatroskaExtractor instances with the provided .

public final intread(ExtractorInput input, PositionHolder seekPosition)

public final voidrelease()

public voidseek(long position, long timeUs)

public final booleansniff(ExtractorInput input)

protected voidstartMasterElement(int id, long contentPosition, long contentSize)

Called when the start of a master element is encountered.

protected voidstringElement(int id, java.lang.String value)

Called when a string element is encountered.

from java.lang.Objectclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Fields

public static final int FLAG_DISABLE_SEEK_FOR_CUES

Flag to disable seeking for cues.

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_EMIT_RAW_SUBTITLE_DATA

Flag to use the source subtitle formats without modification. If unset, subtitles will be transcoded to MimeTypes.APPLICATION_MEDIA3_CUES during extraction.

public static final ExtractorsFactory FACTORY

Deprecated: Use MatroskaExtractor.newFactory(SubtitleParser.Factory) instead.

Constructors

public MatroskaExtractor()

Deprecated: Use MatroskaExtractor.MatroskaExtractor(SubtitleParser.Factory) instead.

public MatroskaExtractor(int flags)

Deprecated: Use MatroskaExtractor.MatroskaExtractor(SubtitleParser.Factory, int) instead.

public MatroskaExtractor(SubtitleParser.Factory subtitleParserFactory)

Constructs an instance.

Parameters:

subtitleParserFactory: The for parsing subtitles during extraction.

public MatroskaExtractor(SubtitleParser.Factory subtitleParserFactory, int flags)

Constructs an instance.

Parameters:

subtitleParserFactory: The for parsing subtitles during extraction.
flags: Flags that control the extractor's behavior.

Methods

public static ExtractorsFactory newFactory(SubtitleParser.Factory subtitleParserFactory)

Creates a factory for MatroskaExtractor instances with the provided .

public final boolean sniff(ExtractorInput input)

public final void init(ExtractorOutput output)

public void seek(long position, long timeUs)

public final void release()

public final int read(ExtractorInput input, PositionHolder seekPosition)

protected int getElementType(int id)

Maps an element ID to a corresponding type.

See also: EbmlProcessor.getElementType(int)

protected boolean isLevel1Element(int id)

Checks if the given id is that of a level 1 element.

See also: EbmlProcessor.isLevel1Element(int)

protected void startMasterElement(int id, long contentPosition, long contentSize)

Called when the start of a master element is encountered.

See also: EbmlProcessor.startMasterElement(int, long, long)

protected void endMasterElement(int id)

Called when the end of a master element is encountered.

See also: EbmlProcessor.endMasterElement(int)

protected void integerElement(int id, long value)

Called when an integer element is encountered.

See also: EbmlProcessor.integerElement(int, long)

protected void floatElement(int id, double value)

Called when a float element is encountered.

See also: EbmlProcessor.floatElement(int, double)

protected void stringElement(int id, java.lang.String value)

Called when a string element is encountered.

See also: EbmlProcessor.stringElement(int, String)

protected void binaryElement(int id, int contentSize, ExtractorInput input)

Called when a binary element is encountered.

See also: EbmlProcessor.binaryElement(int, int, ExtractorInput)

protected void handleBlockAddIDExtraData(MatroskaExtractor.Track track, ExtractorInput input, int contentSize)

protected void handleBlockAdditionalData(MatroskaExtractor.Track track, int blockAdditionalId, ExtractorInput input, int contentSize)

protected MatroskaExtractor.Track getCurrentTrack(int currentElementId)

Returns the track corresponding to the current TrackEntry element.

Source

/*
 * 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 androidx.media3.extractor.mkv;

import static androidx.media3.common.util.Assertions.checkArgument;
import static androidx.media3.common.util.Assertions.checkNotNull;
import static androidx.media3.common.util.Assertions.checkState;
import static androidx.media3.common.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 androidx.media3.common.C;
import androidx.media3.common.ColorInfo;
import androidx.media3.common.DrmInitData;
import androidx.media3.common.DrmInitData.SchemeData;
import androidx.media3.common.Format;
import androidx.media3.common.MimeTypes;
import androidx.media3.common.ParserException;
import androidx.media3.common.util.Log;
import androidx.media3.common.util.LongArray;
import androidx.media3.common.util.NullableType;
import androidx.media3.common.util.ParsableByteArray;
import androidx.media3.common.util.UnstableApi;
import androidx.media3.common.util.Util;
import androidx.media3.container.NalUnitUtil;
import androidx.media3.extractor.AacUtil;
import androidx.media3.extractor.AvcConfig;
import androidx.media3.extractor.ChunkIndex;
import androidx.media3.extractor.DolbyVisionConfig;
import androidx.media3.extractor.Extractor;
import androidx.media3.extractor.ExtractorInput;
import androidx.media3.extractor.ExtractorOutput;
import androidx.media3.extractor.ExtractorsFactory;
import androidx.media3.extractor.HevcConfig;
import androidx.media3.extractor.MpegAudioUtil;
import androidx.media3.extractor.PositionHolder;
import androidx.media3.extractor.SeekMap;
import androidx.media3.extractor.TrackOutput;
import androidx.media3.extractor.TrueHdSampleRechunker;
import androidx.media3.extractor.text.SubtitleParser;
import androidx.media3.extractor.text.SubtitleTranscodingExtractorOutput;
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.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. */
@UnstableApi
public class MatroskaExtractor implements Extractor {

  /**
   * Creates a factory for {@link MatroskaExtractor} instances with the provided {@link
   * SubtitleParser.Factory}.
   */
  public static ExtractorsFactory newFactory(SubtitleParser.Factory subtitleParserFactory) {
    return () -> new Extractor[] {new MatroskaExtractor(subtitleParserFactory)};
  }

  /**
   * Flags controlling the behavior of the extractor. Possible flag values are {@link
   * #FLAG_DISABLE_SEEK_FOR_CUES} and {#FLAG_EMIT_RAW_SUBTITLE_DATA}.
   */
  @Documented
  @Retention(RetentionPolicy.SOURCE)
  @Target(TYPE_USE)
  @IntDef(
      flag = true,
      value = {FLAG_DISABLE_SEEK_FOR_CUES, FLAG_EMIT_RAW_SUBTITLE_DATA})
  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;

  /**
   * Flag to use the source subtitle formats without modification. If unset, subtitles will be
   * transcoded to {@link MimeTypes#APPLICATION_MEDIA3_CUES} during extraction.
   */
  public static final int FLAG_EMIT_RAW_SUBTITLE_DATA = 1 << 1; // 2

  /**
   * @deprecated Use {@link #newFactory(SubtitleParser.Factory)} instead.
   */
  @Deprecated
  public static final ExtractorsFactory FACTORY =
      () ->
          new Extractor[] {
            new MatroskaExtractor(SubtitleParser.Factory.UNSUPPORTED, FLAG_EMIT_RAW_SUBTITLE_DATA)
          };

  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_BITS_PER_CHANNEL = 0x55B2;
  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;
  private final boolean parseSubtitlesDuringExtraction;
  private final SubtitleParser.Factory subtitleParserFactory;

  // 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.INDEX_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.INDEX_UNSET;
  private long seekPositionAfterBuildingCues = C.INDEX_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;

  /**
   * @deprecated Use {@link #MatroskaExtractor(SubtitleParser.Factory)} instead.
   */
  @Deprecated
  public MatroskaExtractor() {
    this(new DefaultEbmlReader(), FLAG_EMIT_RAW_SUBTITLE_DATA, SubtitleParser.Factory.UNSUPPORTED);
  }

  /**
   * @deprecated Use {@link #MatroskaExtractor(SubtitleParser.Factory, int)} instead.
   */
  @Deprecated
  public MatroskaExtractor(@Flags int flags) {
    this(
        new DefaultEbmlReader(),
        flags | FLAG_EMIT_RAW_SUBTITLE_DATA,
        SubtitleParser.Factory.UNSUPPORTED);
  }

  /**
   * Constructs an instance.
   *
   * @param subtitleParserFactory The {@link SubtitleParser.Factory} for parsing subtitles during
   *     extraction.
   */
  public MatroskaExtractor(SubtitleParser.Factory subtitleParserFactory) {
    this(new DefaultEbmlReader(), /* flags= */ 0, subtitleParserFactory);
  }

  /**
   * Constructs an instance.
   *
   * @param subtitleParserFactory The {@link SubtitleParser.Factory} for parsing subtitles during
   *     extraction.
   * @param flags Flags that control the extractor's behavior.
   */
  public MatroskaExtractor(SubtitleParser.Factory subtitleParserFactory, @Flags int flags) {
    this(new DefaultEbmlReader(), flags, subtitleParserFactory);
  }

  /* package */ MatroskaExtractor(
      EbmlReader reader, @Flags int flags, SubtitleParser.Factory subtitleParserFactory) {
    this.reader = reader;
    this.reader.init(new InnerEbmlProcessor());
    this.subtitleParserFactory = subtitleParserFactory;
    seekForCuesEnabled = (flags & FLAG_DISABLE_SEEK_FOR_CUES) == 0;
    parseSubtitlesDuringExtraction = (flags & FLAG_EMIT_RAW_SUBTITLE_DATA) == 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;
    extractorOutput =
        parseSubtitlesDuringExtraction
            ? new SubtitleTranscodingExtractorOutput(output, subtitleParserFactory)
            : 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_BITS_PER_CHANNEL:
      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.INDEX_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.INDEX_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.INDEX_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.INDEX_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_BITS_PER_CHANNEL:
        assertInTrackEntry(id);
        currentTrack.hasColorInfo = true;
        currentTrack.bitsPerChannel = (int) value;
        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.INDEX_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.INDEX_UNSET) {
      seekPosition.position = seekPositionAfterBuildingCues;
      seekPositionAfterBuildingCues = C.INDEX_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 bitsPerChannel = 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 if (audioBitDepth == 24) {
            pcmEncoding = C.ENCODING_PCM_24BIT_BIG_ENDIAN;
          } else if (audioBitDepth == 32) {
            pcmEncoding = C.ENCODING_PCM_32BIT_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.Builder()
                  .setColorSpace(colorSpace)
                  .setColorRange(colorRange)
                  .setColorTransfer(colorTransfer)
                  .setHdrStaticInfo(hdrStaticInfo)
                  .setLumaBitdepth(bitsPerChannel)
                  .setChromaBitdepth(bitsPerChannel)
                  .build();
        }
        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(projectionPoseRoll, 90f) == 0) {
            rotationDegrees = 90;
          } else if (Float.compare(projectionPoseRoll, -180f) == 0
              || Float.compare(projectionPoseRoll, 180f) == 0) {
            rotationDegrees = 180;
          } else if (Float.compare(projectionPoseRoll, -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;
    }
  }
}