Make SeiReader injectable to H26xReaders

This CL is a no-op refactor but allows defining the outputted
channels through the TsPayloadReaderFactory.

Issue:#2161

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=146243736

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

@@ -74,10 +74,11 @@ public TsPayloadReader createPayloadReader(int streamType, EsInfo esInfo) {
       case TsExtractor.TS_STREAM_TYPE_H262:
         return new PesReader(new H262Reader());
       case TsExtractor.TS_STREAM_TYPE_H264:
-        return isSet(FLAG_IGNORE_H264_STREAM) ? null : new PesReader(
-            new H264Reader(isSet(FLAG_ALLOW_NON_IDR_KEYFRAMES), isSet(FLAG_DETECT_ACCESS_UNITS)));
+        return isSet(FLAG_IGNORE_H264_STREAM) ? null
+            : new PesReader(new H264Reader(new SeiReader(), isSet(FLAG_ALLOW_NON_IDR_KEYFRAMES),
+                isSet(FLAG_DETECT_ACCESS_UNITS)));
       case TsExtractor.TS_STREAM_TYPE_H265:
-        return new PesReader(new H265Reader());
+        return new PesReader(new H265Reader(new SeiReader()));
       case TsExtractor.TS_STREAM_TYPE_SPLICE_INFO:
         return isSet(FLAG_IGNORE_SPLICE_INFO_STREAM)
             ? null : new SectionReader(new SpliceInfoSectionReader());

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

@@ -39,6 +39,7 @@
   private static final int NAL_UNIT_TYPE_SPS = 7; // Sequence parameter set
   private static final int NAL_UNIT_TYPE_PPS = 8; // Picture parameter set
 
+  private final SeiReader seiReader;
   private final boolean allowNonIdrKeyframes;
   private final boolean detectAccessUnits;
   private final NalUnitTargetBuffer sps;
@@ -49,7 +50,6 @@
 
   private String formatId;
   private TrackOutput output;
-  private SeiReader seiReader;
   private SampleReader sampleReader;
 
   // State that should not be reset on seek.
@@ -62,15 +62,17 @@
   private final ParsableByteArray seiWrapper;
 
   /**
+   * @param seiReader An SEI reader for consuming closed caption channels.
    * @param allowNonIdrKeyframes Whether to treat samples consisting of non-IDR I slices as
    *     synchronization samples (key-frames).
    * @param detectAccessUnits Whether to split the input stream into access units (samples) based on
    *     slice headers. Pass {@code false} if the stream contains access unit delimiters (AUDs).
    */
-  public H264Reader(boolean allowNonIdrKeyframes, boolean detectAccessUnits) {
-    prefixFlags = new boolean[3];
+  public H264Reader(SeiReader seiReader, boolean allowNonIdrKeyframes, boolean detectAccessUnits) {
+    this.seiReader = seiReader;
     this.allowNonIdrKeyframes = allowNonIdrKeyframes;
     this.detectAccessUnits = detectAccessUnits;
+    prefixFlags = new boolean[3];
     sps = new NalUnitTargetBuffer(NAL_UNIT_TYPE_SPS, 128);
     pps = new NalUnitTargetBuffer(NAL_UNIT_TYPE_PPS, 128);
     sei = new NalUnitTargetBuffer(NAL_UNIT_TYPE_SEI, 128);
@@ -93,9 +95,7 @@ public void createTracks(ExtractorOutput extractorOutput, TrackIdGenerator idGen
     formatId = idGenerator.getFormatId();
     output = extractorOutput.track(idGenerator.getTrackId());
     sampleReader = new SampleReader(output, allowNonIdrKeyframes, detectAccessUnits);
-    idGenerator.generateNewId();
-    seiReader = new SeiReader(extractorOutput.track(idGenerator.getTrackId()),
-        idGenerator.getFormatId());
+    seiReader.createTracks(extractorOutput, idGenerator);
   }
 
   @Override

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

@@ -44,10 +44,11 @@
   private static final int PREFIX_SEI_NUT = 39;
   private static final int SUFFIX_SEI_NUT = 40;
 
+  private final SeiReader seiReader;
+
   private String formatId;
   private TrackOutput output;
   private SampleReader sampleReader;
-  private SeiReader seiReader;
 
   // State that should not be reset on seek.
   private boolean hasOutputFormat;
@@ -67,7 +68,11 @@
   // Scratch variables to avoid allocations.
   private final ParsableByteArray seiWrapper;
 
-  public H265Reader() {
+  /**
+   * @param seiReader An SEI reader for consuming closed caption channels.
+   */
+  public H265Reader(SeiReader seiReader) {
+    this.seiReader = seiReader;
     prefixFlags = new boolean[3];
     vps = new NalUnitTargetBuffer(VPS_NUT, 128);
     sps = new NalUnitTargetBuffer(SPS_NUT, 128);
@@ -95,9 +100,7 @@ public void createTracks(ExtractorOutput extractorOutput, TrackIdGenerator idGen
     formatId = idGenerator.getFormatId();
     output = extractorOutput.track(idGenerator.getTrackId());
     sampleReader = new SampleReader(output);
-    idGenerator.generateNewId();
-    seiReader = new SeiReader(extractorOutput.track(idGenerator.getTrackId()),
-        idGenerator.getFormatId());
+    seiReader.createTracks(extractorOutput, idGenerator);
   }
 
   @Override

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

@@ -16,7 +16,9 @@
 package com.google.android.exoplayer2.extractor.ts;
 
 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.text.cea.CeaUtil;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableByteArray;
@@ -26,12 +28,13 @@
  */
 /* package */ final class SeiReader {
 
-  private final TrackOutput output;
+  private TrackOutput output;
 
-  public SeiReader(TrackOutput output, String formatId) {
-    this.output = output;
-    output.format(Format.createTextSampleFormat(formatId, MimeTypes.APPLICATION_CEA608, null,
-        Format.NO_VALUE, 0, null, null));
+  public void createTracks(ExtractorOutput extractorOutput, TrackIdGenerator idGenerator) {
+    idGenerator.generateNewId();
+    output = extractorOutput.track(idGenerator.getTrackId());
+    output.format(Format.createTextSampleFormat(idGenerator.getFormatId(),
+        MimeTypes.APPLICATION_CEA608, null, Format.NO_VALUE, 0, null, null));
   }
 
   public void consume(long pesTimeUs, ParsableByteArray seiBuffer) {