androidx · TsaiHao · Jul 10, 2026
diff --git a/RELEASENOTES.md b/RELEASENOTES.md
@@ -24,6 +24,11 @@
         Custom `AssetLoader` implementations must implement these new methods.
 *   Track Selection:
 *   Extractors:
+    *   Fix corrupted AC-3, DTS and LPCM audio when playing DVD-style MPEG-PS
+        content, by stripping the `private_stream_1` sub-stream header from each
+        PES packet in `PsExtractor` before the payload is passed to the audio
+        reader
+        ([#3327](https://github.com/androidx/media/issues/3327)).
 *   Inspector:
 *   Inspector Frame:
 *   Audio:

diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/PsExtractor.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/PsExtractor.java
@@ -260,7 +260,11 @@ public int read(ExtractorInput input, PositionHolder seekPosition) throws IOExce
         if (elementaryStreamReader != null) {
           TrackIdGenerator idGenerator = new TrackIdGenerator(streamId, MAX_STREAM_ID_PLUS_ONE);
           elementaryStreamReader.createTracks(output, idGenerator);
-          payloadReader = new PesReader(elementaryStreamReader, timestampAdjuster);
+          payloadReader =
+              new PesReader(
+                  elementaryStreamReader,
+                  timestampAdjuster,
+                  /* isPrivateStream1= */ streamId == PRIVATE_STREAM_1);
           psPayloadReaders.put(streamId, payloadReader);
         }
       }
@@ -328,16 +332,24 @@ private static final class PesReader {
     private final ElementaryStreamReader pesPayloadReader;
     private final TimestampAdjuster timestampAdjuster;
     private final ParsableBitArray pesScratch;
+    // Whether this reader consumes the MPEG-PS private_stream_1 (0xBD), which in DVD-style content
+    // carries a sub-stream header (sub_stream_id, number_of_frame_headers and
+    // first_access_unit_pointer) before the audio elementary stream.
+    private final boolean isPrivateStream1;
 
     private boolean ptsFlag;
     private boolean dtsFlag;
     private boolean seenFirstDts;
     private int extendedHeaderLength;
     private long timeUs;
 
-    public PesReader(ElementaryStreamReader pesPayloadReader, TimestampAdjuster timestampAdjuster) {
+    public PesReader(
+        ElementaryStreamReader pesPayloadReader,
+        TimestampAdjuster timestampAdjuster,
+        boolean isPrivateStream1) {
       this.pesPayloadReader = pesPayloadReader;
       this.timestampAdjuster = timestampAdjuster;
+      this.isPrivateStream1 = isPrivateStream1;
       pesScratch = new ParsableBitArray(new byte[PES_SCRATCH_SIZE]);
     }
 
@@ -366,12 +378,39 @@ public void consume(ParsableByteArray data) throws ParserException {
       data.readBytes(pesScratch.data, 0, extendedHeaderLength);
       pesScratch.setPosition(0);
       parseHeaderExtension();
+      // For DVD-style private_stream_1 (AC-3/DTS/LPCM), a sub-stream header follows the PES header
+      // and precedes the audio elementary stream. It must be stripped so it isn't fed into the
+      // audio reader as elementary data, which would corrupt the audio frame spanning this PES
+      // boundary (see ISO/IEC 13818-1 / DVD-Video PS spec).
+      maybeSkipPrivateStream1SubStreamHeader(data);
       pesPayloadReader.packetStarted(timeUs, TsPayloadReader.FLAG_DATA_ALIGNMENT_INDICATOR);
       pesPayloadReader.consume(data);
       // We always have complete PES packets with program stream.
       pesPayloadReader.packetFinished();
     }
 
+    /**
+     * Skips the DVD-style private_stream_1 sub-stream header, if present, so that {@code data} is
+     * positioned at the start of the audio elementary stream.
+     *
+     * <p>In DVD-Video and similar MPEG-PS content, each private_stream_1 (0xBD) PES packet begins
+     * with a 4-byte header: {@code sub_stream_id} (1 byte, 0x80-0x87 for AC-3, 0x88-0x8F for DTS,
+     * 0xA0-0xA7 for LPCM), {@code number_of_frame_headers} (1 byte) and {@code
+     * first_access_unit_pointer} (2 bytes). These bytes are not part of the audio elementary stream
+     * and must not be forwarded to the audio reader.
+     */
+    private void maybeSkipPrivateStream1SubStreamHeader(ParsableByteArray data) {
+      if (!isPrivateStream1 || data.bytesLeft() < 4) {
+        return;
+      }
+      int subStreamId = data.peekUnsignedByte();
+      // AC-3 (0x80-0x87), DTS (0x88-0x8F) and LPCM (0xA0-0xA7) sub-streams carry the 4-byte header.
+      if ((subStreamId >= 0x80 && subStreamId <= 0x8F)
+          || (subStreamId >= 0xA0 && subStreamId <= 0xA7)) {
+        data.skipBytes(4);
+      }
+    }
+
     private void consumeEndOfInput() {
       pesPayloadReader.endOfInputReached();
     }

diff --git a/libraries/extractor/src/test/java/androidx/media3/extractor/ts/PsExtractorTest.java b/libraries/extractor/src/test/java/androidx/media3/extractor/ts/PsExtractorTest.java
@@ -44,4 +44,12 @@ public void sampleWithH262AndMpegAudio() throws Exception {
   public void sampleWithAc3() throws Exception {
     ExtractorAsserts.assertBehavior(PsExtractor::new, "media/ts/sample_ac3.ps", simulationConfig);
   }
+
+  @Test
+  public void sampleWithAc3StraddlingPesBoundaries() throws Exception {
+    // Regression test for a private_stream_1 (0xBD) sample whose AC-3 frames straddle PES packet
+    // boundaries, so the DVD sub-stream header preceding each packet's payload must be stripped.
+    ExtractorAsserts.assertBehavior(
+        PsExtractor::new, "media/ts/sample_ac3_straddle.ps", simulationConfig);
+  }
 }
diff --git a/libraries/test_data/src/test/assets/extractordumps/ts/sample_ac3_straddle.ps.0.dump b/libraries/test_data/src/test/assets/extractordumps/ts/sample_ac3_straddle.ps.0.dump
@@ -0,0 +1,173 @@
+seekMap:
+  isSeekable = true
+  duration = 1201344
+  getPosition(0) = [[timeUs=0, position=0]]
+  getPosition(1) = [[timeUs=1, position=0]]
+  getPosition(600672) = [[timeUs=600672, position=35805]]
+  getPosition(1201344) = [[timeUs=1201344, position=71799]]
+numberOfTracks = 2
+track 189:
+  total output bytes = 19200
+  sample count = 25
+  format 0:
+    averageBitrate = 192000
+    peakBitrate = 192000
+    id = 189
+    sampleMimeType = audio/ac3
+    channelCount = 2
+    sampleRate = 48000
+  sample 0:
+    time = 61333
+    flags = 1
+    data = length 768, hash 4513D6ED
+  sample 1:
+    time = 93333
+    flags = 1
+    data = length 768, hash F7DD71AD
+  sample 2:
+    time = 157333
+    flags = 1
+    data = length 768, hash B46BDFC2
+  sample 3:
+    time = 189333
+    flags = 1
+    data = length 768, hash 6E3DC97F
+  sample 4:
+    time = 221333
+    flags = 1
+    data = length 768, hash BCF0EE73
+  sample 5:
+    time = 253333
+    flags = 1
+    data = length 768, hash 4FD0241F
+  sample 6:
+    time = 285333
+    flags = 1
+    data = length 768, hash DF256D70
+  sample 7:
+    time = 317333
+    flags = 1
+    data = length 768, hash BD3A8741
+  sample 8:
+    time = 349333
+    flags = 1
+    data = length 768, hash 6CDA87FA
+  sample 9:
+    time = 381333
+    flags = 1
+    data = length 768, hash D7542AD6
+  sample 10:
+    time = 413333
+    flags = 1
+    data = length 768, hash 650B3B21
+  sample 11:
+    time = 445333
+    flags = 1
+    data = length 768, hash 7AA9EA5
+  sample 12:
+    time = 477333
+    flags = 1
+    data = length 768, hash 36E854AB
+  sample 13:
+    time = 509333
+    flags = 1
+    data = length 768, hash 1958F2B0
+  sample 14:
+    time = 541333
+    flags = 1
+    data = length 768, hash E12C6DFC
+  sample 15:
+    time = 573333
+    flags = 1
+    data = length 768, hash 64E149B3
+  sample 16:
+    time = 605333
+    flags = 1
+    data = length 768, hash A053FE3F
+  sample 17:
+    time = 637333
+    flags = 1
+    data = length 768, hash 326041DB
+  sample 18:
+    time = 669333
+    flags = 1
+    data = length 768, hash 865250F
+  sample 19:
+    time = 701333
+    flags = 1
+    data = length 768, hash B45ADB43
+  sample 20:
+    time = 733333
+    flags = 1
+    data = length 768, hash 99626351
+  sample 21:
+    time = 765333
+    flags = 1
+    data = length 768, hash BCED46AE
+  sample 22:
+    time = 797333
+    flags = 1
+    data = length 768, hash 63B6188F
+  sample 23:
+    time = 829333
+    flags = 1
+    data = length 768, hash 86C6C28B
+  sample 24:
+    time = 861333
+    flags = 1
+    data = length 768, hash A1D014D1
+track 224:
+  total output bytes = 52248
+  sample count = 11
+  format 0:
+    id = 224
+    sampleMimeType = video/mpeg2
+    width = 160
+    height = 120
+    initializationData:
+      data = length 22, hash 3B91971B
+  sample 0:
+    time = 66666
+    flags = 1
+    data = length 5986, hash 6A578416
+  sample 1:
+    time = 133333
+    flags = 0
+    data = length 5571, hash A276297C
+  sample 2:
+    time = 200000
+    flags = 0
+    data = length 4475, hash 50693038
+  sample 3:
+    time = 266666
+    flags = 0
+    data = length 5187, hash 8AD660F2
+  sample 4:
+    time = 333333
+    flags = 0
+    data = length 4552, hash 773C4FC3
+  sample 5:
+    time = 400000
+    flags = 0
+    data = length 5611, hash A70A9C09
+  sample 6:
+    time = 466666
+    flags = 0
+    data = length 4740, hash F8C7264F
+  sample 7:
+    time = 533333
+    flags = 0
+    data = length 3679, hash BEF11657
+  sample 8:
+    time = 600000
+    flags = 0
+    data = length 2910, hash 5F82B9AA
+  sample 9:
+    time = 666666
+    flags = 0
+    data = length 3357, hash 91082EE0
+  sample 10:
+    time = 733333
+    flags = 0
+    data = length 2471, hash B011430D
+tracksEnded = true