Fix handling of E-AC-3 streams with AC-3 frames

Issue: #6602 PiperOrigin-RevId: 287816831

Fix handling of E-AC-3 streams with AC-3 frames
Issue: #6602 PiperOrigin-RevId: 287816831
7fd0b1d8 · andrewlewis · Oliver Woodman · 1edcc6c4 · 7fd0b1d8 · 7fd0b1d8
Commit 7fd0b1d8 authored Jan 02, 2020 by andrewlewis Committed by Oliver Woodman Jan 17, 2020
Showing with 39 additions and 39 deletions
RELEASENOTES.md
library/core/src/main/java/com/google/android/exoplayer2/audio/Ac3Util.java
library/core/src/main/java/com/google/android/exoplayer2/audio/DefaultAudioSink.java
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -12,6 +12,8 @@
  ([#6733](https://github.com/google/ExoPlayer/issues/6733)). Incorrect handling
  could previously cause downloads to be paused when they should have been able
  to proceed.
+* Fix handling of E-AC-3 streams that contain AC-3 syncframes
+  ([#6602](https://github.com/google/ExoPlayer/issues/6602)).
 ### 2.11.1 (2019-12-20) ###

--- a/library/core/src/main/java/com/google/android/exoplayer2/audio/Ac3Util.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/audio/Ac3Util.java
@@ -31,7 +31,7 @@ import java.nio.ByteBuffer;
 /**
 * Utility methods for parsing Dolby TrueHD and (E-)AC-3 syncframes. (E-)AC-3 parsing follows the
- * definition in ETSI TS 102 366 V1.2.1.
+ * definition in ETSI TS 102 366 V1.4.1.
 */
 public final class Ac3Util {
@@ -39,8 +39,8 @@ public final class Ac3Util {
  public static final class SyncFrameInfo {
    /**
-     * AC3 stream types. See also ETSI TS 102 366 E.1.3.1.1. One of {@link #STREAM_TYPE_UNDEFINED},
+     * AC3 stream types. See also E.1.3.1.1. One of {@link #STREAM_TYPE_UNDEFINED}, {@link
-     * {@link #STREAM_TYPE_TYPE0}, {@link #STREAM_TYPE_TYPE1} or {@link #STREAM_TYPE_TYPE2}.
+     * #STREAM_TYPE_TYPE0}, {@link #STREAM_TYPE_TYPE1} or {@link #STREAM_TYPE_TYPE2}.
     */
    @Documented
    @Retention(RetentionPolicy.SOURCE)
@@ -114,9 +114,7 @@ public final class Ac3Util {
   * The number of new samples per (E-)AC-3 audio block.
   */
  private static final int AUDIO_SAMPLES_PER_AUDIO_BLOCK = 256;
-  /**
+  /** Each syncframe has 6 blocks that provide 256 new audio samples. See subsection 4.1. */
-   * Each syncframe has 6 blocks that provide 256 new audio samples. See ETSI TS 102 366 4.1.
-   */
  private static final int AC3_SYNCFRAME_AUDIO_SAMPLE_COUNT = 6 * AUDIO_SAMPLES_PER_AUDIO_BLOCK;
  /**
   * Number of audio blocks per E-AC-3 syncframe, indexed by numblkscod.
@@ -134,20 +132,21 @@ public final class Ac3Util {
   * Channel counts, indexed by acmod.
   */
  private static final int[] CHANNEL_COUNT_BY_ACMOD = new int[] {2, 1, 2, 3, 3, 4, 4, 5};
-  /**
+  /** Nominal bitrates in kbps, indexed by frmsizecod / 2. (See table 4.13.) */
-   * Nominal bitrates in kbps, indexed by frmsizecod / 2. (See ETSI TS 102 366 table 4.13.)
+  private static final int[] BITRATE_BY_HALF_FRMSIZECOD =
-   */
+      new int[] {
-  private static final int[] BITRATE_BY_HALF_FRMSIZECOD = new int[] {32, 40, 48, 56, 64, 80, 96,
+        32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 448, 512, 576, 640
-      112, 128, 160, 192, 224, 256, 320, 384, 448, 512, 576, 640};
+      };
-  /**
+  /** 16-bit words per syncframe, indexed by frmsizecod / 2. (See table 4.13.) */
-   * 16-bit words per syncframe, indexed by frmsizecod / 2. (See ETSI TS 102 366 table 4.13.)
+  private static final int[] SYNCFRAME_SIZE_WORDS_BY_HALF_FRMSIZECOD_44_1 =
-   */
+      new int[] {
-  private static final int[] SYNCFRAME_SIZE_WORDS_BY_HALF_FRMSIZECOD_44_1 = new int[] {69, 87, 104,
+        69, 87, 104, 121, 139, 174, 208, 243, 278, 348, 417, 487, 557, 696, 835, 975, 1114, 1253,
-      121, 139, 174, 208, 243, 278, 348, 417, 487, 557, 696, 835, 975, 1114, 1253, 1393};
+        1393
+      };
  /**
-   * Returns the AC-3 format given {@code data} containing the AC3SpecificBox according to ETSI TS
+   * Returns the AC-3 format given {@code data} containing the AC3SpecificBox according to Annex F.
-   * 102 366 Annex F. The reading position of {@code data} will be modified.
+   * The reading position of {@code data} will be modified.
   *
   * @param data The AC3SpecificBox to parse.
   * @param trackId The track identifier to set on the format.
@@ -179,8 +178,8 @@ public final class Ac3Util {
  }
  /**
-   * Returns the E-AC-3 format given {@code data} containing the EC3SpecificBox according to ETSI TS
+   * Returns the E-AC-3 format given {@code data} containing the EC3SpecificBox according to Annex
-   * 102 366 Annex F. The reading position of {@code data} will be modified.
+   * F. The reading position of {@code data} will be modified.
   *
   * @param data The EC3SpecificBox to parse.
   * @param trackId The track identifier to set on the format.
@@ -243,9 +242,10 @@ public final class Ac3Util {
  public static SyncFrameInfo parseAc3SyncframeInfo(ParsableBitArray data) {
    int initialPosition = data.getPosition();
    data.skipBits(40);
-    boolean isEac3 = data.readBits(5) == 16; // See bsid in subsection E.1.3.1.6.
+    // Parse the bitstream ID for AC-3 and E-AC-3 (see subsections 4.3, E.1.2 and E.1.3.1.6).
+    boolean isEac3 = data.readBits(5) > 10;
    data.setPosition(initialPosition);
-    String mimeType;
+    @Nullable String mimeType;
    @StreamType int streamType = SyncFrameInfo.STREAM_TYPE_UNDEFINED;
    int sampleRate;
    int acmod;
@@ -254,7 +254,7 @@ public final class Ac3Util {
    boolean lfeon;
    int channelCount;
    if (isEac3) {
-      // Syntax from ETSI TS 102 366 V1.2.1 subsections E.1.2.1 and E.1.2.2.
+      // Subsection E.1.2.
      data.skipBits(16); // syncword
      switch (data.readBits(2)) { // strmtyp
        case 0:
@@ -472,7 +472,8 @@ public final class Ac3Util {
    if (data.length < 6) {
      return C.LENGTH_UNSET;
    }
-    boolean isEac3 = ((data[5] & 0xFF) >> 3) == 16; // See bsid in subsection E.1.3.1.6.
+    // Parse the bitstream ID for AC-3 and E-AC-3 (see subsections 4.3, E.1.2 and E.1.3.1.6).
+    boolean isEac3 = ((data[5] & 0xF8) >> 3) > 10;
    if (isEac3) {
      int frmsiz = (data[2] & 0x07) << 8; // Most significant 3 bits.
      frmsiz |= data[3] & 0xFF; // Least significant 8 bits.
@@ -485,24 +486,22 @@ public final class Ac3Util {
  }
  /**
-   * Returns the number of audio samples in an AC-3 syncframe.
+   * Reads the number of audio samples represented by the given (E-)AC-3 syncframe. The buffer's
-   */
-  public static int getAc3SyncframeAudioSampleCount() {
-    return AC3_SYNCFRAME_AUDIO_SAMPLE_COUNT;
-  }
-  /**
-   * Reads the number of audio samples represented by the given E-AC-3 syncframe. The buffer's
   * position is not modified.
   *
   * @param buffer The {@link ByteBuffer} from which to read the syncframe.
   * @return The number of audio samples represented by the syncframe.
   */
-  public static int parseEAc3SyncframeAudioSampleCount(ByteBuffer buffer) {
+  public static int parseAc3SyncframeAudioSampleCount(ByteBuffer buffer) {
-    // See ETSI TS 102 366 subsection E.1.2.2.
+    // Parse the bitstream ID for AC-3 and E-AC-3 (see subsections 4.3, E.1.2 and E.1.3.1.6).
-    int fscod = (buffer.get(buffer.position() + 4) & 0xC0) >> 6;
+    boolean isEac3 = ((buffer.get(buffer.position() + 5) & 0xF8) >> 3) > 10;
-    return AUDIO_SAMPLES_PER_AUDIO_BLOCK * (fscod == 0x03 ? 6
+    if (isEac3) {
-        : BLOCKS_PER_SYNCFRAME_BY_NUMBLKSCOD[(buffer.get(buffer.position() + 4) & 0x30) >> 4]);
+      int fscod = (buffer.get(buffer.position() + 4) & 0xC0) >> 6;
+      int numblkscod = fscod == 0x03 ? 3 : (buffer.get(buffer.position() + 4) & 0x30) >> 4;
+      return BLOCKS_PER_SYNCFRAME_BY_NUMBLKSCOD[numblkscod] * AUDIO_SAMPLES_PER_AUDIO_BLOCK;
+    } else {
+      return AC3_SYNCFRAME_AUDIO_SAMPLE_COUNT;
+    }
  }
  /**

--- a/library/core/src/main/java/com/google/android/exoplayer2/audio/DefaultAudioSink.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/audio/DefaultAudioSink.java
@@ -1166,10 +1166,9 @@ public final class DefaultAudioSink implements AudioSink {
      case C.ENCODING_DTS_HD:
        return DtsUtil.parseDtsAudioSampleCount(buffer);
      case C.ENCODING_AC3:
-        return Ac3Util.getAc3SyncframeAudioSampleCount();
      case C.ENCODING_E_AC3:
      case C.ENCODING_E_AC3_JOC:
-        return Ac3Util.parseEAc3SyncframeAudioSampleCount(buffer);
+        return Ac3Util.parseAc3SyncframeAudioSampleCount(buffer);
      case C.ENCODING_AC4:
        return Ac4Util.parseAc4SyncframeAudioSampleCount(buffer);
      case C.ENCODING_DOLBY_TRUEHD: