Add package level NonNull to extractor.ts

Also remove most classes from the nullness blacklist

PiperOrigin-RevId: 288494712

library/core/src/main/java/com/google/android/exoplayer2/audio/DtsUtil.java

@@ -81,7 +81,10 @@ public final class DtsUtil {
    * @return The DTS format parsed from data in the header.
    */
   public static Format parseDtsFormat(
-      byte[] frame, String trackId, @Nullable String language, @Nullable DrmInitData drmInitData) {
+      byte[] frame,
+      @Nullable String trackId,
+      @Nullable String language,
+      @Nullable DrmInitData drmInitData) {
     ParsableBitArray frameBits = getNormalizedFrameHeader(frame);
     frameBits.skipBits(32 + 1 + 5 + 1 + 7 + 14); // SYNC, FTYPE, SHORT, CPF, NBLKS, FSIZE
     int amode = frameBits.readBits(6);

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/Ac3Reader.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.extractor.ts;
 
 import androidx.annotation.IntDef;
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.audio.Ac3Util;
@@ -23,11 +24,15 @@ import com.google.android.exoplayer2.audio.Ac3Util.SyncFrameInfo;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.ParsableBitArray;
 import com.google.android.exoplayer2.util.ParsableByteArray;
+import com.google.android.exoplayer2.util.Util;
 import java.lang.annotation.Documented;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /**
  * Parses a continuous (E-)AC-3 byte stream and extracts individual samples.
@@ -47,10 +52,10 @@ public final class Ac3Reader implements ElementaryStreamReader {
 
   private final ParsableBitArray headerScratchBits;
   private final ParsableByteArray headerScratchBytes;
-  private final String language;
+  @Nullable private final String language;
 
-  private String trackFormatId;
+  @MonotonicNonNull private String formatId;
-  private TrackOutput output;
+  @MonotonicNonNull private TrackOutput output;
 
   @State private int state;
   private int bytesRead;
@@ -60,7 +65,7 @@ public final class Ac3Reader implements ElementaryStreamReader {
 
   // Used when parsing the header.
   private long sampleDurationUs;
-  private Format format;
+  @MonotonicNonNull private Format format;
   private int sampleSize;
 
   // Used when reading the samples.
@@ -78,7 +83,7 @@ public final class Ac3Reader implements ElementaryStreamReader {
    *
    * @param language Track language.
    */
-  public Ac3Reader(String language) {
+  public Ac3Reader(@Nullable String language) {
     headerScratchBits = new ParsableBitArray(new byte[HEADER_SIZE]);
     headerScratchBytes = new ParsableByteArray(headerScratchBits.data);
     state = STATE_FINDING_SYNC;
@@ -95,7 +100,7 @@ public final class Ac3Reader implements ElementaryStreamReader {
   @Override
   public void createTracks(ExtractorOutput extractorOutput, TrackIdGenerator generator) {
     generator.generateNewId();
-    trackFormatId = generator.getFormatId();
+    formatId = generator.getFormatId();
     output = extractorOutput.track(generator.getTrackId(), C.TRACK_TYPE_AUDIO);
   }
 
@@ -106,6 +111,7 @@ public final class Ac3Reader implements ElementaryStreamReader {
 
   @Override
   public void consume(ParsableByteArray data) {
+    Assertions.checkStateNotNull(output); // Asserts that createTracks has been called.
     while (data.bytesLeft() > 0) {
       switch (state) {
         case STATE_FINDING_SYNC:
@@ -185,19 +191,28 @@ public final class Ac3Reader implements ElementaryStreamReader {
     return false;
   }
 
-  /**
+  /** Parses the sample header. */
-   * Parses the sample header.
+  @RequiresNonNull("output")
-   */
-  @SuppressWarnings("ReferenceEquality")
   private void parseHeader() {
     headerScratchBits.setPosition(0);
     SyncFrameInfo frameInfo = Ac3Util.parseAc3SyncframeInfo(headerScratchBits);
-    if (format == null || frameInfo.channelCount != format.channelCount
+    if (format == null
+        || frameInfo.channelCount != format.channelCount
         || frameInfo.sampleRate != format.sampleRate
-        || frameInfo.mimeType != format.sampleMimeType) {
+        || Util.areEqual(frameInfo.mimeType, format.sampleMimeType)) {
-      format = Format.createAudioSampleFormat(trackFormatId, frameInfo.mimeType, null,
+      format =
-          Format.NO_VALUE, Format.NO_VALUE, frameInfo.channelCount, frameInfo.sampleRate, null,
+          Format.createAudioSampleFormat(
-          null, 0, language);
+              formatId,
+              frameInfo.mimeType,
+              null,
+              Format.NO_VALUE,
+              Format.NO_VALUE,
+              frameInfo.channelCount,
+              frameInfo.sampleRate,
+              null,
+              null,
+              0,
+              language);
       output.format(format);
     }
     sampleSize = frameInfo.frameSize;

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/Ac4Reader.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.extractor.ts;
 
 import androidx.annotation.IntDef;
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.audio.Ac4Util;
@@ -23,12 +24,15 @@ import com.google.android.exoplayer2.audio.Ac4Util.SyncFrameInfo;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableBitArray;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import java.lang.annotation.Documented;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /** Parses a continuous AC-4 byte stream and extracts individual samples. */
 public final class Ac4Reader implements ElementaryStreamReader {
@@ -44,10 +48,10 @@ public final class Ac4Reader implements ElementaryStreamReader {
 
   private final ParsableBitArray headerScratchBits;
   private final ParsableByteArray headerScratchBytes;
-  private final String language;
+  @Nullable private final String language;
 
-  private String trackFormatId;
+  @MonotonicNonNull private String formatId;
-  private TrackOutput output;
+  @MonotonicNonNull private TrackOutput output;
 
   @State private int state;
   private int bytesRead;
@@ -58,7 +62,7 @@ public final class Ac4Reader implements ElementaryStreamReader {
 
   // Used when parsing the header.
   private long sampleDurationUs;
-  private Format format;
+  @MonotonicNonNull private Format format;
   private int sampleSize;
 
   // Used when reading the samples.
@@ -74,7 +78,7 @@ public final class Ac4Reader implements ElementaryStreamReader {
    *
    * @param language Track language.
    */
-  public Ac4Reader(String language) {
+  public Ac4Reader(@Nullable String language) {
     headerScratchBits = new ParsableBitArray(new byte[Ac4Util.HEADER_SIZE_FOR_PARSER]);
     headerScratchBytes = new ParsableByteArray(headerScratchBits.data);
     state = STATE_FINDING_SYNC;
@@ -95,7 +99,7 @@ public final class Ac4Reader implements ElementaryStreamReader {
   @Override
   public void createTracks(ExtractorOutput extractorOutput, TrackIdGenerator generator) {
     generator.generateNewId();
-    trackFormatId = generator.getFormatId();
+    formatId = generator.getFormatId();
     output = extractorOutput.track(generator.getTrackId(), C.TRACK_TYPE_AUDIO);
   }
 
@@ -106,6 +110,7 @@ public final class Ac4Reader implements ElementaryStreamReader {
 
   @Override
   public void consume(ParsableByteArray data) {
+    Assertions.checkStateNotNull(output); // Asserts that createTracks has been called.
     while (data.bytesLeft() > 0) {
       switch (state) {
         case STATE_FINDING_SYNC:
@@ -185,7 +190,7 @@ public final class Ac4Reader implements ElementaryStreamReader {
   }
 
   /** Parses the sample header. */
-  @SuppressWarnings("ReferenceEquality")
+  @RequiresNonNull("output")
   private void parseHeader() {
     headerScratchBits.setPosition(0);
     SyncFrameInfo frameInfo = Ac4Util.parseAc4SyncframeInfo(headerScratchBits);
@@ -195,7 +200,7 @@ public final class Ac4Reader implements ElementaryStreamReader {
         || !MimeTypes.AUDIO_AC4.equals(format.sampleMimeType)) {
       format =
           Format.createAudioSampleFormat(
-              trackFormatId,
+              formatId,
               MimeTypes.AUDIO_AC4,
               /* codecs= */ null,
               /* bitrate= */ Format.NO_VALUE,

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/AdtsReader.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.extractor.ts;
 
 import android.util.Pair;
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.ParserException;
@@ -23,13 +24,18 @@ import com.google.android.exoplayer2.extractor.DummyTrackOutput;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.CodecSpecificDataUtil;
 import com.google.android.exoplayer2.util.Log;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableBitArray;
 import com.google.android.exoplayer2.util.ParsableByteArray;
+import com.google.android.exoplayer2.util.Util;
 import java.util.Arrays;
 import java.util.Collections;
+import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /**
  * Parses a continuous ADTS byte stream and extracts individual frames.
@@ -62,11 +68,11 @@ public final class AdtsReader implements ElementaryStreamReader {
   private final boolean exposeId3;
   private final ParsableBitArray adtsScratch;
   private final ParsableByteArray id3HeaderBuffer;
-  private final String language;
+  @Nullable private final String language;
 
-  private String formatId;
+  @MonotonicNonNull private String formatId;
-  private TrackOutput output;
+  @MonotonicNonNull private TrackOutput output;
-  private TrackOutput id3Output;
+  @MonotonicNonNull private TrackOutput id3Output;
 
   private int state;
   private int bytesRead;
@@ -90,7 +96,7 @@ public final class AdtsReader implements ElementaryStreamReader {
   // Used when reading the samples.
   private long timeUs;
 
-  private TrackOutput currentOutput;
+  @MonotonicNonNull private TrackOutput currentOutput;
   private long currentSampleDuration;
 
   /**
@@ -104,7 +110,7 @@ public final class AdtsReader implements ElementaryStreamReader {
    * @param exposeId3 True if the reader should expose ID3 information.
    * @param language Track language.
    */
-  public AdtsReader(boolean exposeId3, String language) {
+  public AdtsReader(boolean exposeId3, @Nullable String language) {
     adtsScratch = new ParsableBitArray(new byte[HEADER_SIZE + CRC_SIZE]);
     id3HeaderBuffer = new ParsableByteArray(Arrays.copyOf(ID3_IDENTIFIER, ID3_HEADER_SIZE));
     setFindingSampleState();
@@ -130,6 +136,7 @@ public final class AdtsReader implements ElementaryStreamReader {
     idGenerator.generateNewId();
     formatId = idGenerator.getFormatId();
     output = extractorOutput.track(idGenerator.getTrackId(), C.TRACK_TYPE_AUDIO);
+    currentOutput = output;
     if (exposeId3) {
       idGenerator.generateNewId();
       id3Output = extractorOutput.track(idGenerator.getTrackId(), C.TRACK_TYPE_METADATA);
@@ -147,6 +154,7 @@ public final class AdtsReader implements ElementaryStreamReader {
 
   @Override
   public void consume(ParsableByteArray data) throws ParserException {
+    assertTracksCreated();
     while (data.bytesLeft() > 0) {
       switch (state) {
         case STATE_FINDING_SAMPLE:
@@ -425,9 +433,8 @@ public final class AdtsReader implements ElementaryStreamReader {
     return true;
   }
 
-  /**
+  /** Parses the Id3 header. */
-   * Parses the Id3 header.
+  @RequiresNonNull("id3Output")
-   */
   private void parseId3Header() {
     id3Output.sampleData(id3HeaderBuffer, ID3_HEADER_SIZE);
     id3HeaderBuffer.setPosition(ID3_SIZE_OFFSET);
@@ -435,9 +442,8 @@ public final class AdtsReader implements ElementaryStreamReader {
         id3HeaderBuffer.readSynchSafeInt() + ID3_HEADER_SIZE);
   }
 
-  /**
+  /** Parses the sample header. */
-   * Parses the sample header.
+  @RequiresNonNull("output")
-   */
   private void parseAdtsHeader() throws ParserException {
     adtsScratch.setPosition(0);
 
@@ -487,9 +493,8 @@ public final class AdtsReader implements ElementaryStreamReader {
     setReadingSampleState(output, sampleDurationUs, 0, sampleSize);
   }
 
-  /**
+  /** Reads the rest of the sample */
-   * Reads the rest of the sample
+  @RequiresNonNull("currentOutput")
-   */
   private void readSample(ParsableByteArray data) {
     int bytesToRead = Math.min(data.bytesLeft(), sampleSize - bytesRead);
     currentOutput.sampleData(data, bytesToRead);
@@ -501,4 +506,10 @@ public final class AdtsReader implements ElementaryStreamReader {
     }
   }
 
+  @EnsuresNonNull({"output", "currentOutput", "id3Output"})
+  private void assertTracksCreated() {
+    Assertions.checkNotNull(output);
+    Util.castNonNull(currentOutput);
+    Util.castNonNull(id3Output);
+  }
 }

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/DefaultTsPayloadReaderFactory.java

@@ -17,6 +17,7 @@ package com.google.android.exoplayer2.extractor.ts;
 
 import android.util.SparseArray;
 import androidx.annotation.IntDef;
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.EsInfo;
 import com.google.android.exoplayer2.text.cea.Cea708InitializationData;
@@ -134,6 +135,7 @@ public final class DefaultTsPayloadReaderFactory implements TsPayloadReader.Fact
     return new SparseArray<>();
   }
 
+  @Nullable
   @Override
   public TsPayloadReader createPayloadReader(int streamType, EsInfo esInfo) {
     switch (streamType) {
@@ -247,7 +249,7 @@ public final class DefaultTsPayloadReaderFactory implements TsPayloadReader.Fact
           // Skip reserved (8).
           scratchDescriptorData.skipBytes(1);
 
-          List<byte[]> initializationData = null;
+          @Nullable List<byte[]> initializationData = null;
           // The wide_aspect_ratio flag only has meaning for CEA-708.
           if (isDigital) {
             boolean isWideAspectRatio = (flags & 0x40) != 0;

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/DtsReader.java

@@ -15,13 +15,17 @@
  */
 package com.google.android.exoplayer2.extractor.ts;
 
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.audio.DtsUtil;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.ParsableByteArray;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /**
  * Parses a continuous DTS byte stream and extracts individual samples.
@@ -35,10 +39,10 @@ public final class DtsReader implements ElementaryStreamReader {
   private static final int HEADER_SIZE = 18;
 
   private final ParsableByteArray headerScratchBytes;
-  private final String language;
+  @Nullable private final String language;
 
-  private String formatId;
+  @MonotonicNonNull private String formatId;
-  private TrackOutput output;
+  @MonotonicNonNull private TrackOutput output;
 
   private int state;
   private int bytesRead;
@@ -48,7 +52,7 @@ public final class DtsReader implements ElementaryStreamReader {
 
   // Used when parsing the header.
   private long sampleDurationUs;
-  private Format format;
+  @MonotonicNonNull private Format format;
   private int sampleSize;
 
   // Used when reading the samples.
@@ -59,7 +63,7 @@ public final class DtsReader implements ElementaryStreamReader {
    *
    * @param language Track language.
    */
-  public DtsReader(String language) {
+  public DtsReader(@Nullable String language) {
     headerScratchBytes = new ParsableByteArray(new byte[HEADER_SIZE]);
     state = STATE_FINDING_SYNC;
     this.language = language;
@@ -86,6 +90,7 @@ public final class DtsReader implements ElementaryStreamReader {
 
   @Override
   public void consume(ParsableByteArray data) {
+    Assertions.checkStateNotNull(output); // Asserts that createTracks has been called.
     while (data.bytesLeft() > 0) {
       switch (state) {
         case STATE_FINDING_SYNC:
@@ -162,9 +167,8 @@ public final class DtsReader implements ElementaryStreamReader {
     return false;
   }
 
-  /**
+  /** Parses the sample header. */
-   * Parses the sample header.
+  @RequiresNonNull("output")
-   */
   private void parseHeader() {
     byte[] frameData = headerScratchBytes.data;
     if (format == null) {

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/DvbSubtitleReader.java

@@ -64,12 +64,12 @@ public final class DvbSubtitleReader implements ElementaryStreamReader {
           Format.createImageSampleFormat(
               idGenerator.getFormatId(),
               MimeTypes.APPLICATION_DVBSUBS,
-              null,
+              /* codecs= */ null,
               Format.NO_VALUE,
-              0,
+              /* selectionFlags= */ 0,
               Collections.singletonList(subtitleInfo.initializationData),
               subtitleInfo.language,
-              null));
+              /* drmInitData= */ null));
       outputs[i] = output;
     }
   }

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/H262Reader.java

@@ -16,16 +16,20 @@
 package com.google.android.exoplayer2.extractor.ts;
 
 import android.util.Pair;
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.NalUnitUtil;
 import com.google.android.exoplayer2.util.ParsableByteArray;
+import com.google.android.exoplayer2.util.Util;
 import java.util.Arrays;
 import java.util.Collections;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
 /**
  * Parses a continuous H262 byte stream and extracts individual frames.
@@ -38,27 +42,27 @@ public final class H262Reader implements ElementaryStreamReader {
   private static final int START_GROUP = 0xB8;
   private static final int START_USER_DATA = 0xB2;
 
-  private String formatId;
+  @MonotonicNonNull private String formatId;
-  private TrackOutput output;
+  @MonotonicNonNull private TrackOutput output;
 
   // Maps (frame_rate_code - 1) indices to values, as defined in ITU-T H.262 Table 6-4.
   private static final double[] FRAME_RATE_VALUES = new double[] {
       24000d / 1001, 24, 25, 30000d / 1001, 30, 50, 60000d / 1001, 60};
 
+  @Nullable private final UserDataReader userDataReader;
+  @Nullable private final ParsableByteArray userDataParsable;
+
+  // State that should be reset on seek.
+  @Nullable private final NalUnitTargetBuffer userData;
+  private final boolean[] prefixFlags;
+  private final CsdBuffer csdBuffer;
+  private long totalBytesWritten;
+  private boolean startedFirstSample;
+
   // State that should not be reset on seek.
   private boolean hasOutputFormat;
   private long frameDurationUs;
 
-  private final UserDataReader userDataReader;
-  private final ParsableByteArray userDataParsable;
-
-  // State that should be reset on seek.
-  private final boolean[] prefixFlags;
-  private final CsdBuffer csdBuffer;
-  private final NalUnitTargetBuffer userData;
-  private long totalBytesWritten;
-  private boolean startedFirstSample;
-
   // Per packet state that gets reset at the start of each packet.
   private long pesTimeUs;
 
@@ -72,7 +76,7 @@ public final class H262Reader implements ElementaryStreamReader {
     this(null);
   }
 
-  /* package */ H262Reader(UserDataReader userDataReader) {
+  /* package */ H262Reader(@Nullable UserDataReader userDataReader) {
     this.userDataReader = userDataReader;
     prefixFlags = new boolean[4];
     csdBuffer = new CsdBuffer(128);
@@ -89,7 +93,7 @@ public final class H262Reader implements ElementaryStreamReader {
   public void seek() {
     NalUnitUtil.clearPrefixFlags(prefixFlags);
     csdBuffer.reset();
-    if (userDataReader != null) {
+    if (userData != null) {
       userData.reset();
     }
     totalBytesWritten = 0;
@@ -114,6 +118,7 @@ public final class H262Reader implements ElementaryStreamReader {
 
   @Override
   public void consume(ParsableByteArray data) {
+    Assertions.checkStateNotNull(output); // Asserts that createTracks has been called.
     int offset = data.getPosition();
     int limit = data.limit();
     byte[] dataArray = data.data;
@@ -130,7 +135,7 @@ public final class H262Reader implements ElementaryStreamReader {
         if (!hasOutputFormat) {
           csdBuffer.onData(dataArray, offset, limit);
         }
-        if (userDataReader != null) {
+        if (userData != null) {
           userData.appendToNalUnit(dataArray, offset, limit);
         }
         return;
@@ -157,7 +162,7 @@ public final class H262Reader implements ElementaryStreamReader {
           hasOutputFormat = true;
         }
       }
-      if (userDataReader != null) {
+      if (userData != null) {
         int bytesAlreadyPassed = 0;
         if (lengthToStartCode > 0) {
           userData.appendToNalUnit(dataArray, offset, startCodeOffset);
@@ -167,8 +172,8 @@ public final class H262Reader implements ElementaryStreamReader {
 
         if (userData.endNalUnit(bytesAlreadyPassed)) {
           int unescapedLength = NalUnitUtil.unescapeStream(userData.nalData, userData.nalLength);
-          userDataParsable.reset(userData.nalData, unescapedLength);
+          Util.castNonNull(userDataParsable).reset(userData.nalData, unescapedLength);
-          userDataReader.consume(sampleTimeUs, userDataParsable);
+          Util.castNonNull(userDataReader).consume(sampleTimeUs, userDataParsable);
         }
 
         if (startCodeValue == START_USER_DATA && data.data[startCodeOffset + 2] == 0x1) {
@@ -211,10 +216,10 @@ public final class H262Reader implements ElementaryStreamReader {
    *
    * @param csdBuffer The csd buffer.
    * @param formatId The id for the generated format. May be null.
-   * @return A pair consisting of the {@link Format} and the frame duration in microseconds, or
+   * @return A pair consisting of the {@link Format} and the frame duration in microseconds, or 0 if
-   *     0 if the duration could not be determined.
+   *     the duration could not be determined.
    */
-  private static Pair<Format, Long> parseCsdBuffer(CsdBuffer csdBuffer, String formatId) {
+  private static Pair<Format, Long> parseCsdBuffer(CsdBuffer csdBuffer, @Nullable String formatId) {
     byte[] csdData = Arrays.copyOf(csdBuffer.data, csdBuffer.length);
 
     int firstByte = csdData[4] & 0xFF;

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/H264Reader.java

@@ -23,15 +23,21 @@ import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.CodecSpecificDataUtil;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.NalUnitUtil;
 import com.google.android.exoplayer2.util.NalUnitUtil.SpsData;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.ParsableNalUnitBitArray;
+import com.google.android.exoplayer2.util.Util;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /**
  * Parses a continuous H264 byte stream and extracts individual frames.
@@ -51,9 +57,9 @@ public final class H264Reader implements ElementaryStreamReader {
   private long totalBytesWritten;
   private final boolean[] prefixFlags;
 
-  private String formatId;
+  @MonotonicNonNull private String formatId;
-  private TrackOutput output;
+  @MonotonicNonNull private TrackOutput output;
-  private SampleReader sampleReader;
+  @MonotonicNonNull private SampleReader sampleReader;
 
   // State that should not be reset on seek.
   private boolean hasOutputFormat;
@@ -87,13 +93,15 @@ public final class H264Reader implements ElementaryStreamReader {
 
   @Override
   public void seek() {
+    totalBytesWritten = 0;
+    randomAccessIndicator = false;
     NalUnitUtil.clearPrefixFlags(prefixFlags);
     sps.reset();
     pps.reset();
     sei.reset();
-    sampleReader.reset();
+    if (sampleReader != null) {
-    totalBytesWritten = 0;
+      sampleReader.reset();
-    randomAccessIndicator = false;
+    }
   }
 
   @Override
@@ -113,6 +121,8 @@ public final class H264Reader implements ElementaryStreamReader {
 
   @Override
   public void consume(ParsableByteArray data) {
+    assertTracksCreated();
+
     int offset = data.getPosition();
     int limit = data.limit();
     byte[] dataArray = data.data;
@@ -159,6 +169,7 @@ public final class H264Reader implements ElementaryStreamReader {
     // Do nothing.
   }
 
+  @RequiresNonNull("sampleReader")
   private void startNalUnit(long position, int nalUnitType, long pesTimeUs) {
     if (!hasOutputFormat || sampleReader.needsSpsPps()) {
       sps.startNalUnit(nalUnitType);
@@ -168,6 +179,7 @@ public final class H264Reader implements ElementaryStreamReader {
     sampleReader.startNalUnit(position, nalUnitType, pesTimeUs);
   }
 
+  @RequiresNonNull("sampleReader")
   private void nalUnitData(byte[] dataArray, int offset, int limit) {
     if (!hasOutputFormat || sampleReader.needsSpsPps()) {
       sps.appendToNalUnit(dataArray, offset, limit);
@@ -177,6 +189,7 @@ public final class H264Reader implements ElementaryStreamReader {
     sampleReader.appendToNalUnit(dataArray, offset, limit);
   }
 
+  @RequiresNonNull({"output", "sampleReader"})
   private void endNalUnit(long position, int offset, int discardPadding, long pesTimeUs) {
     if (!hasOutputFormat || sampleReader.needsSpsPps()) {
       sps.endNalUnit(discardPadding);
@@ -237,6 +250,12 @@ public final class H264Reader implements ElementaryStreamReader {
     }
   }
 
+  @EnsuresNonNull({"output", "sampleReader"})
+  private void assertTracksCreated() {
+    Assertions.checkStateNotNull(output);
+    Util.castNonNull(sampleReader);
+  }
+
   /** Consumes a stream of NAL units and outputs samples. */
   private static final class SampleReader {
 
@@ -478,7 +497,7 @@ public final class H264Reader implements ElementaryStreamReader {
       private boolean isComplete;
       private boolean hasSliceType;
 
-      private SpsData spsData;
+      @Nullable private SpsData spsData;
       private int nalRefIdc;
       private int sliceType;
       private int frameNum;
@@ -542,6 +561,8 @@ public final class H264Reader implements ElementaryStreamReader {
 
       private boolean isFirstVclNalUnitOfPicture(SliceHeaderData other) {
         // See ISO 14496-10 subsection 7.4.1.2.4.
+        SpsData spsData = Assertions.checkStateNotNull(this.spsData);
+        SpsData otherSpsData = Assertions.checkStateNotNull(other.spsData);
         return isComplete
             && (!other.isComplete
                 || frameNum != other.frameNum
@@ -552,15 +573,15 @@ public final class H264Reader implements ElementaryStreamReader {
                     && bottomFieldFlag != other.bottomFieldFlag)
                 || (nalRefIdc != other.nalRefIdc && (nalRefIdc == 0 || other.nalRefIdc == 0))
                 || (spsData.picOrderCountType == 0
-                    && other.spsData.picOrderCountType == 0
+                    && otherSpsData.picOrderCountType == 0
                     && (picOrderCntLsb != other.picOrderCntLsb
                         || deltaPicOrderCntBottom != other.deltaPicOrderCntBottom))
                 || (spsData.picOrderCountType == 1
-                    && other.spsData.picOrderCountType == 1
+                    && otherSpsData.picOrderCountType == 1
                     && (deltaPicOrderCnt0 != other.deltaPicOrderCnt0
                         || deltaPicOrderCnt1 != other.deltaPicOrderCnt1))
                 || idrPicFlag != other.idrPicFlag
-                || (idrPicFlag && other.idrPicFlag && idrPicId != other.idrPicId));
+                || (idrPicFlag && idrPicId != other.idrPicId));
       }
     }
   }

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/H265Reader.java

@@ -20,12 +20,18 @@ import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Log;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.NalUnitUtil;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.ParsableNalUnitBitArray;
+import com.google.android.exoplayer2.util.Util;
 import java.util.Collections;
+import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /**
  * Parses a continuous H.265 byte stream and extracts individual frames.
@@ -46,9 +52,9 @@ public final class H265Reader implements ElementaryStreamReader {
 
   private final SeiReader seiReader;
 
-  private String formatId;
+  @MonotonicNonNull private String formatId;
-  private TrackOutput output;
+  @MonotonicNonNull private TrackOutput output;
-  private SampleReader sampleReader;
+  @MonotonicNonNull private SampleReader sampleReader;
 
   // State that should not be reset on seek.
   private boolean hasOutputFormat;
@@ -84,14 +90,16 @@ public final class H265Reader implements ElementaryStreamReader {
 
   @Override
   public void seek() {
+    totalBytesWritten = 0;
     NalUnitUtil.clearPrefixFlags(prefixFlags);
     vps.reset();
     sps.reset();
     pps.reset();
     prefixSei.reset();
     suffixSei.reset();
-    sampleReader.reset();
+    if (sampleReader != null) {
-    totalBytesWritten = 0;
+      sampleReader.reset();
+    }
   }
 
   @Override
@@ -111,6 +119,8 @@ public final class H265Reader implements ElementaryStreamReader {
 
   @Override
   public void consume(ParsableByteArray data) {
+    assertTracksCreated();
+
     while (data.bytesLeft() > 0) {
       int offset = data.getPosition();
       int limit = data.limit();
@@ -160,6 +170,7 @@ public final class H265Reader implements ElementaryStreamReader {
     // Do nothing.
   }
 
+  @RequiresNonNull("sampleReader")
   private void startNalUnit(long position, int offset, int nalUnitType, long pesTimeUs) {
     if (hasOutputFormat) {
       sampleReader.startNalUnit(position, offset, nalUnitType, pesTimeUs);
@@ -172,6 +183,7 @@ public final class H265Reader implements ElementaryStreamReader {
     suffixSei.startNalUnit(nalUnitType);
   }
 
+  @RequiresNonNull("sampleReader")
   private void nalUnitData(byte[] dataArray, int offset, int limit) {
     if (hasOutputFormat) {
       sampleReader.readNalUnitData(dataArray, offset, limit);
@@ -184,6 +196,7 @@ public final class H265Reader implements ElementaryStreamReader {
     suffixSei.appendToNalUnit(dataArray, offset, limit);
   }
 
+  @RequiresNonNull({"output", "sampleReader"})
   private void endNalUnit(long position, int offset, int discardPadding, long pesTimeUs) {
     if (hasOutputFormat) {
       sampleReader.endNalUnit(position, offset);
@@ -214,8 +227,11 @@ public final class H265Reader implements ElementaryStreamReader {
     }
   }
 
-  private static Format parseMediaFormat(String formatId, NalUnitTargetBuffer vps,
+  private static Format parseMediaFormat(
-      NalUnitTargetBuffer sps, NalUnitTargetBuffer pps) {
+      @Nullable String formatId,
+      NalUnitTargetBuffer vps,
+      NalUnitTargetBuffer sps,
+      NalUnitTargetBuffer pps) {
     // Build codec-specific data.
     byte[] csd = new byte[vps.nalLength + sps.nalLength + pps.nalLength];
     System.arraycopy(vps.nalData, 0, csd, 0, vps.nalLength);
@@ -389,6 +405,12 @@ public final class H265Reader implements ElementaryStreamReader {
     }
   }
 
+  @EnsuresNonNull({"output", "sampleReader"})
+  private void assertTracksCreated() {
+    Assertions.checkStateNotNull(output);
+    Util.castNonNull(sampleReader);
+  }
+
   private static final class SampleReader {
 
     /**

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/Id3Reader.java

@@ -23,9 +23,11 @@ import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Log;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableByteArray;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
 /**
  * Parses ID3 data and extracts individual text information frames.
@@ -36,7 +38,7 @@ public final class Id3Reader implements ElementaryStreamReader {
 
   private final ParsableByteArray id3Header;
 
-  private TrackOutput output;
+  @MonotonicNonNull private TrackOutput output;
 
   // State that should be reset on seek.
   private boolean writingSample;
@@ -76,6 +78,7 @@ public final class Id3Reader implements ElementaryStreamReader {
 
   @Override
   public void consume(ParsableByteArray data) {
+    Assertions.checkStateNotNull(output); // Asserts that createTracks has been called.
     if (!writingSample) {
       return;
     }
@@ -106,6 +109,7 @@ public final class Id3Reader implements ElementaryStreamReader {
 
   @Override
   public void packetFinished() {
+    Assertions.checkStateNotNull(output); // Asserts that createTracks has been called.
     if (!writingSample || sampleSize == 0 || sampleBytesRead != sampleSize) {
       return;
     }

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/LatmReader.java

@@ -23,11 +23,14 @@ import com.google.android.exoplayer2.ParserException;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.CodecSpecificDataUtil;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableBitArray;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import java.util.Collections;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /**
  * Parses and extracts samples from an AAC/LATM elementary stream.
@@ -43,14 +46,14 @@ public final class LatmReader implements ElementaryStreamReader {
   private static final int SYNC_BYTE_FIRST = 0x56;
   private static final int SYNC_BYTE_SECOND = 0xE0;
 
-  private final String language;
+  @Nullable private final String language;
   private final ParsableByteArray sampleDataBuffer;
   private final ParsableBitArray sampleBitArray;
 
   // Track output info.
-  private TrackOutput output;
+  @MonotonicNonNull private TrackOutput output;
-  private Format format;
+  @MonotonicNonNull private String formatId;
-  private String formatId;
+  @MonotonicNonNull private Format format;
 
   // Parser state info.
   private int state;
@@ -99,6 +102,7 @@ public final class LatmReader implements ElementaryStreamReader {
 
   @Override
   public void consume(ParsableByteArray data) throws ParserException {
+    Assertions.checkStateNotNull(output); // Asserts that createTracks has been called.
     int bytesToRead;
     while (data.bytesLeft() > 0) {
       switch (state) {
@@ -150,6 +154,7 @@ public final class LatmReader implements ElementaryStreamReader {
    *
    * @param data A {@link ParsableBitArray} containing the AudioMuxElement's bytes.
    */
+  @RequiresNonNull("output")
   private void parseAudioMuxElement(ParsableBitArray data) throws ParserException {
     boolean useSameStreamMux = data.readBit();
     if (!useSameStreamMux) {
@@ -173,9 +178,8 @@ public final class LatmReader implements ElementaryStreamReader {
     }
   }
 
-  /**
+  /** Parses a StreamMuxConfig as defined in ISO/IEC 14496-3:2009 Section 1.7.3.1, Table 1.42. */
-   * Parses a StreamMuxConfig as defined in ISO/IEC 14496-3:2009 Section 1.7.3.1, Table 1.42.
+  @RequiresNonNull("output")
-   */
   private void parseStreamMuxConfig(ParsableBitArray data) throws ParserException {
     int audioMuxVersion = data.readBits(1);
     audioMuxVersionA = audioMuxVersion == 1 ? data.readBits(1) : 0;
@@ -198,9 +202,19 @@ public final class LatmReader implements ElementaryStreamReader {
         data.setPosition(startPosition);
         byte[] initData = new byte[(readBits + 7) / 8];
         data.readBits(initData, 0, readBits);
-        Format format = Format.createAudioSampleFormat(formatId, MimeTypes.AUDIO_AAC, null,
+        Format format =
-            Format.NO_VALUE, Format.NO_VALUE, channelCount, sampleRateHz,
+            Format.createAudioSampleFormat(
-            Collections.singletonList(initData), null, 0, language);
+                formatId,
+                MimeTypes.AUDIO_AAC,
+                /* codecs= */ null,
+                Format.NO_VALUE,
+                Format.NO_VALUE,
+                channelCount,
+                sampleRateHz,
+                Collections.singletonList(initData),
+                /* drmInitData= */ null,
+                /* selectionFlags= */ 0,
+                language);
         if (!format.equals(this.format)) {
           this.format = format;
           sampleDurationUs = (C.MICROS_PER_SECOND * 1024) / format.sampleRate;
@@ -280,6 +294,7 @@ public final class LatmReader implements ElementaryStreamReader {
     }
   }
 
+  @RequiresNonNull("output")
   private void parsePayloadMux(ParsableBitArray data, int muxLengthBytes) {
     // The start of sample data in
     int bitPosition = data.getPosition();

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/MpegAudioReader.java

@@ -21,7 +21,11 @@ import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.extractor.MpegAudioHeader;
 import com.google.android.exoplayer2.extractor.TrackOutput;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.ParsableByteArray;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /**
  * Parses a continuous MPEG Audio byte stream and extracts individual frames.
@@ -36,10 +40,10 @@ public final class MpegAudioReader implements ElementaryStreamReader {
 
   private final ParsableByteArray headerScratch;
   private final MpegAudioHeader header;
-  private final String language;
+  @Nullable private final String language;
 
-  private String formatId;
+  @MonotonicNonNull private TrackOutput output;
-  private TrackOutput output;
+  @MonotonicNonNull private String formatId;
 
   private int state;
   private int frameBytesRead;
@@ -59,7 +63,7 @@ public final class MpegAudioReader implements ElementaryStreamReader {
     this(null);
   }
 
-  public MpegAudioReader(String language) {
+  public MpegAudioReader(@Nullable String language) {
     state = STATE_FINDING_HEADER;
     // The first byte of an MPEG Audio frame header is always 0xFF.
     headerScratch = new ParsableByteArray(4);
@@ -89,6 +93,7 @@ public final class MpegAudioReader implements ElementaryStreamReader {
 
   @Override
   public void consume(ParsableByteArray data) {
+    Assertions.checkStateNotNull(output); // Asserts that createTracks has been called.
     while (data.bytesLeft() > 0) {
       switch (state) {
         case STATE_FINDING_HEADER:
@@ -146,20 +151,21 @@ public final class MpegAudioReader implements ElementaryStreamReader {
 
   /**
    * Attempts to read the remaining two bytes of the frame header.
-   * <p>
+   *
-   * If a frame header is read in full then the state is changed to {@link #STATE_READING_FRAME},
+   * <p>If a frame header is read in full then the state is changed to {@link #STATE_READING_FRAME},
    * the media format is output if this has not previously occurred, the four header bytes are
    * output as sample data, and the position of the source is advanced to the byte that immediately
    * follows the header.
-   * <p>
+   *
-   * If a frame header is read in full but cannot be parsed then the state is changed to
+   * <p>If a frame header is read in full but cannot be parsed then the state is changed to {@link
-   * {@link #STATE_READING_HEADER}.
+   * #STATE_READING_HEADER}.
-   * <p>
+   *
-   * If a frame header is not read in full then the position of the source is advanced to the limit,
+   * <p>If a frame header is not read in full then the position of the source is advanced to the
-   * and the method should be called again with the next source to continue the read.
+   * limit, and the method should be called again with the next source to continue the read.
    *
    * @param source The source from which to read.
    */
+  @RequiresNonNull("output")
   private void readHeaderRemainder(ParsableByteArray source) {
     int bytesToRead = Math.min(source.bytesLeft(), HEADER_SIZE - frameBytesRead);
     source.readBytes(headerScratch.data, frameBytesRead, bytesToRead);
@@ -195,16 +201,17 @@ public final class MpegAudioReader implements ElementaryStreamReader {
 
   /**
    * Attempts to read the remainder of the frame.
-   * <p>
+   *
-   * If a frame is read in full then true is returned. The frame will have been output, and the
+   * <p>If a frame is read in full then true is returned. The frame will have been output, and the
    * position of the source will have been advanced to the byte that immediately follows the end of
    * the frame.
-   * <p>
+   *
-   * If a frame is not read in full then the position of the source will have been advanced to the
+   * <p>If a frame is not read in full then the position of the source will have been advanced to
-   * limit, and the method should be called again with the next source to continue the read.
+   * the limit, and the method should be called again with the next source to continue the read.
    *
    * @param source The source from which to read.
    */
+  @RequiresNonNull("output")
   private void readFrameRemainder(ParsableByteArray source) {
     int bytesToRead = Math.min(source.bytesLeft(), frameSize - frameBytesRead);
     output.sampleData(source, bytesToRead);
@@ -219,5 +226,4 @@ public final class MpegAudioReader implements ElementaryStreamReader {
     frameBytesRead = 0;
     state = STATE_FINDING_HEADER;
   }
-
 }

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/PesReader.java

@@ -15,13 +15,17 @@
  */
 package com.google.android.exoplayer2.extractor.ts;
 
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ParserException;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Log;
 import com.google.android.exoplayer2.util.ParsableBitArray;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.TimestampAdjuster;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /**
  * Parses PES packet data and extracts samples.
@@ -45,7 +49,7 @@ public final class PesReader implements TsPayloadReader {
   private int state;
   private int bytesRead;
 
-  private TimestampAdjuster timestampAdjuster;
+  @MonotonicNonNull private TimestampAdjuster timestampAdjuster;
   private boolean ptsFlag;
   private boolean dtsFlag;
   private boolean seenFirstDts;
@@ -79,6 +83,8 @@ public final class PesReader implements TsPayloadReader {
 
   @Override
   public final void consume(ParsableByteArray data, @Flags int flags) throws ParserException {
+    Assertions.checkStateNotNull(timestampAdjuster); // Asserts init has been called.
+
     if ((flags & FLAG_PAYLOAD_UNIT_START_INDICATOR) != 0) {
       switch (state) {
         case STATE_FINDING_HEADER:
@@ -119,7 +125,7 @@ public final class PesReader implements TsPayloadReader {
           int readLength = Math.min(MAX_HEADER_EXTENSION_SIZE, extendedHeaderLength);
           // Read as much of the extended header as we're interested in, and skip the rest.
           if (continueRead(data, pesScratch.data, readLength)
-              && continueRead(data, null, extendedHeaderLength)) {
+              && continueRead(data, /* target= */ null, extendedHeaderLength)) {
             parseHeaderExtension();
             flags |= dataAlignmentIndicator ? FLAG_DATA_ALIGNMENT_INDICATOR : 0;
             reader.packetStarted(timeUs, flags);
@@ -162,7 +168,8 @@ public final class PesReader implements TsPayloadReader {
    * @param targetLength The target length of the read.
    * @return Whether the target length has been reached.
    */
-  private boolean continueRead(ParsableByteArray source, byte[] target, int targetLength) {
+  private boolean continueRead(
+      ParsableByteArray source, @Nullable byte[] target, int targetLength) {
     int bytesToRead = Math.min(source.bytesLeft(), targetLength - bytesRead);
     if (bytesToRead <= 0) {
       return true;
@@ -207,6 +214,7 @@ public final class PesReader implements TsPayloadReader {
     return true;
   }
 
+  @RequiresNonNull("timestampAdjuster")
   private void parseHeaderExtension() {
     pesScratch.setPosition(0);
     timeUs = C.TIME_UNSET;

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/PsExtractor.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.extractor.ts;
 
 import android.util.SparseArray;
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ParserException;
 import com.google.android.exoplayer2.extractor.Extractor;
@@ -25,10 +26,13 @@ import com.google.android.exoplayer2.extractor.ExtractorsFactory;
 import com.google.android.exoplayer2.extractor.PositionHolder;
 import com.google.android.exoplayer2.extractor.SeekMap;
 import com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.ParsableBitArray;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.TimestampAdjuster;
 import java.io.IOException;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /**
  * Extracts data from the MPEG-2 PS container format.
@@ -67,8 +71,8 @@ public final class PsExtractor implements Extractor {
   private long lastTrackPosition;
 
   // Accessed only by the loading thread.
-  private PsBinarySearchSeeker psBinarySearchSeeker;
+  @Nullable private PsBinarySearchSeeker psBinarySearchSeeker;
-  private ExtractorOutput output;
+  @MonotonicNonNull private ExtractorOutput output;
   private boolean hasOutputSeekMap;
 
   public PsExtractor() {
@@ -160,6 +164,7 @@ public final class PsExtractor implements Extractor {
   @Override
   public int read(ExtractorInput input, PositionHolder seekPosition)
       throws IOException, InterruptedException {
+    Assertions.checkStateNotNull(output); // Asserts init has been called.
 
     long inputLength = input.getLength();
     boolean canReadDuration = inputLength != C.LENGTH_UNSET;
@@ -221,7 +226,7 @@ public final class PsExtractor implements Extractor {
     PesReader payloadReader = psPayloadReaders.get(streamId);
     if (!foundAllTracks) {
       if (payloadReader == null) {
-        ElementaryStreamReader elementaryStreamReader = null;
+        @Nullable ElementaryStreamReader elementaryStreamReader = null;
         if (streamId == PRIVATE_STREAM_1) {
           // Private stream, used for AC3 audio.
           // NOTE: This may need further parsing to determine if its DTS, but that's likely only
@@ -278,6 +283,7 @@ public final class PsExtractor implements Extractor {
 
   // Internals.
 
+  @RequiresNonNull("output")
   private void maybeOutputSeekMap(long inputLength) {
     if (!hasOutputSeekMap) {
       hasOutputSeekMap = true;

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/SeiReader.java

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.extractor.ts;
 
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
@@ -45,7 +46,7 @@ public final class SeiReader {
       idGenerator.generateNewId();
       TrackOutput output = extractorOutput.track(idGenerator.getTrackId(), C.TRACK_TYPE_TEXT);
       Format channelFormat = closedCaptionFormats.get(i);
-      String channelMimeType = channelFormat.sampleMimeType;
+      @Nullable String channelMimeType = channelFormat.sampleMimeType;
       Assertions.checkArgument(MimeTypes.APPLICATION_CEA608.equals(channelMimeType)
           || MimeTypes.APPLICATION_CEA708.equals(channelMimeType),
           "Invalid closed caption mime type provided: " + channelMimeType);
@@ -69,5 +70,4 @@ public final class SeiReader {
   public void consume(long pesTimeUs, ParsableByteArray seiBuffer) {
     CeaUtil.consume(pesTimeUs, seiBuffer, outputs);
   }
-
 }

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/SpliceInfoSectionReader.java

@@ -19,17 +19,21 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.extractor.TrackOutput;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.TimestampAdjuster;
+import com.google.android.exoplayer2.util.Util;
+import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
 /**
  * Parses splice info sections as defined by SCTE35.
  */
 public final class SpliceInfoSectionReader implements SectionPayloadReader {
 
-  private TimestampAdjuster timestampAdjuster;
+  @MonotonicNonNull private TimestampAdjuster timestampAdjuster;
-  private TrackOutput output;
+  @MonotonicNonNull private TrackOutput output;
   private boolean formatDeclared;
 
   @Override
@@ -44,6 +48,7 @@ public final class SpliceInfoSectionReader implements SectionPayloadReader {
 
   @Override
   public void consume(ParsableByteArray sectionData) {
+    assertInitialized();
     if (!formatDeclared) {
       if (timestampAdjuster.getTimestampOffsetUs() == C.TIME_UNSET) {
         // There is not enough information to initialize the timestamp adjuster.
@@ -59,4 +64,9 @@ public final class SpliceInfoSectionReader implements SectionPayloadReader {
         sampleSize, 0, null);
   }
 
+  @EnsuresNonNull({"timestampAdjuster", "output"})
+  private void assertInitialized() {
+    Assertions.checkStateNotNull(timestampAdjuster);
+    Util.castNonNull(output);
+  }
 }

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/TsExtractor.java

@@ -21,6 +21,7 @@ import android.util.SparseArray;
 import android.util.SparseBooleanArray;
 import android.util.SparseIntArray;
 import androidx.annotation.IntDef;
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ParserException;
 import com.google.android.exoplayer2.extractor.Extractor;
@@ -587,8 +588,11 @@ public final class TsExtractor implements Extractor {
           continue;
         }
 
-        TsPayloadReader reader = mode == MODE_HLS && streamType == TS_STREAM_TYPE_ID3 ? id3Reader
+        @Nullable
-            : payloadReaderFactory.createPayloadReader(streamType, esInfo);
+        TsPayloadReader reader =
+            mode == MODE_HLS && streamType == TS_STREAM_TYPE_ID3
+                ? id3Reader
+                : payloadReaderFactory.createPayloadReader(streamType, esInfo);
         if (mode != MODE_HLS
             || elementaryPid < trackIdToPidScratch.get(trackId, MAX_PID_PLUS_ONE)) {
           trackIdToPidScratch.put(trackId, elementaryPid);
@@ -602,7 +606,7 @@ public final class TsExtractor implements Extractor {
         int trackPid = trackIdToPidScratch.valueAt(i);
         trackIds.put(trackId, true);
         trackPids.put(trackPid, true);
-        TsPayloadReader reader = trackIdToReaderScratch.valueAt(i);
+        @Nullable TsPayloadReader reader = trackIdToReaderScratch.valueAt(i);
         if (reader != null) {
           if (reader != id3Reader) {
             reader.init(timestampAdjuster, output,

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/TsPayloadReader.java

@@ -17,6 +17,7 @@ package com.google.android.exoplayer2.extractor.ts;
 
 import android.util.SparseArray;
 import androidx.annotation.IntDef;
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.ParserException;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.extractor.TrackOutput;
@@ -53,11 +54,11 @@ public interface TsPayloadReader {
      *
      * @param streamType Stream type value as defined in the PMT entry or associated descriptors.
      * @param esInfo Information associated to the elementary stream provided in the PMT.
-     * @return A {@link TsPayloadReader} for the packet stream carried by the provided pid.
+     * @return A {@link TsPayloadReader} for the packet stream carried by the provided pid, or
      *     {@code null} if the stream is not supported.
      */
+    @Nullable
     TsPayloadReader createPayloadReader(int streamType, EsInfo esInfo);
-
   }
 
   /**
@@ -66,18 +67,21 @@ public interface TsPayloadReader {
   final class EsInfo {
 
     public final int streamType;
-    public final String language;
+    @Nullable public final String language;
     public final List<DvbSubtitleInfo> dvbSubtitleInfos;
     public final byte[] descriptorBytes;
 
     /**
-     * @param streamType The type of the stream as defined by the
+     * @param streamType The type of the stream as defined by the {@link TsExtractor}{@code
-     *     {@link TsExtractor}{@code .TS_STREAM_TYPE_*}.
+     *     .TS_STREAM_TYPE_*}.
      * @param language The language of the stream, as defined by ISO/IEC 13818-1, section 2.6.18.
      * @param dvbSubtitleInfos Information about DVB subtitles associated to the stream.
      * @param descriptorBytes The descriptor bytes associated to the stream.
      */
-    public EsInfo(int streamType, String language, List<DvbSubtitleInfo> dvbSubtitleInfos,
+    public EsInfo(
+        int streamType,
+        @Nullable String language,
+        @Nullable List<DvbSubtitleInfo> dvbSubtitleInfos,
         byte[] descriptorBytes) {
       this.streamType = streamType;
       this.language = language;
@@ -134,6 +138,7 @@ public interface TsPayloadReader {
       this.firstTrackId = firstTrackId;
       this.trackIdIncrement = trackIdIncrement;
       trackId = ID_UNSET;
+      formatId = "";
     }
 
     /**

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/UserDataReader.java

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.extractor.ts;
 
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.extractor.ExtractorOutput;
@@ -44,7 +45,7 @@ import java.util.List;
       idGenerator.generateNewId();
       TrackOutput output = extractorOutput.track(idGenerator.getTrackId(), C.TRACK_TYPE_TEXT);
       Format channelFormat = closedCaptionFormats.get(i);
-      String channelMimeType = channelFormat.sampleMimeType;
+      @Nullable String channelMimeType = channelFormat.sampleMimeType;
       Assertions.checkArgument(
           MimeTypes.APPLICATION_CEA608.equals(channelMimeType)
               || MimeTypes.APPLICATION_CEA708.equals(channelMimeType),

library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+@NonNullApi
+package com.google.android.exoplayer2.extractor.ts;
+
+import com.google.android.exoplayer2.util.NonNullApi;

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadHelper.java

@@ -773,7 +773,7 @@ public final class DownloadHelper {
   }
 
   // Initialization of array of Lists.
-  @SuppressWarnings("unchecked")
+  @SuppressWarnings({"unchecked", "rawtypes"})
   private void onMediaPrepared() {
     Assertions.checkNotNull(mediaPreparer);
     Assertions.checkNotNull(mediaPreparer.mediaPeriods);

library/core/src/test/java/com/google/android/exoplayer2/extractor/ts/TsExtractorTest.java

@@ -18,6 +18,7 @@ package com.google.android.exoplayer2.extractor.ts;
 import static com.google.common.truth.Truth.assertThat;
 
 import android.util.SparseArray;
+import androidx.annotation.Nullable;
 import androidx.test.core.app.ApplicationProvider;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.C;
@@ -172,6 +173,7 @@ public final class TsExtractorTest {
       }
     }
 
+    @Nullable
     @Override
     public TsPayloadReader createPayloadReader(int streamType, EsInfo esInfo) {
       if (provideCustomEsReader && streamType == 3) {