Parse and set bitrates in Ac3Reader

PiperOrigin-RevId: 492003800
DiceTechnology · Dec 12, 2022 · 5f73984 · 5f73984
1 parent 2652d0e
commit 5f73984
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Showing 27 changed files with 61 additions and 4 deletions.
diff --git a/library/extractor/src/main/java/com/google/android/exoplayer2/audio/Ac3Util.java b/library/extractor/src/main/java/com/google/android/exoplayer2/audio/Ac3Util.java
@@ -78,20 +78,24 @@ public static final class SyncFrameInfo {
     public final int frameSize;
     /** Number of audio samples in the frame. */
     public final int sampleCount;
+    /** The bitrate of audio samples. */
+    public final int bitrate;
 
     private SyncFrameInfo(
         @Nullable String mimeType,
         @StreamType int streamType,
         int channelCount,
         int sampleRate,
         int frameSize,
-        int sampleCount) {
+        int sampleCount,
+        int bitrate) {
       this.mimeType = mimeType;
       this.streamType = streamType;
       this.channelCount = channelCount;
       this.sampleRate = sampleRate;
       this.frameSize = frameSize;
       this.sampleCount = sampleCount;
+      this.bitrate = bitrate;
     }
   }
 
@@ -259,6 +263,7 @@ public static SyncFrameInfo parseAc3SyncframeInfo(ParsableBitArray data) {
     int sampleCount;
     boolean lfeon;
     int channelCount;
+    int bitrate;
     if (isEac3) {
       // Subsection E.1.2.
       data.skipBits(16); // syncword
@@ -291,6 +296,7 @@ public static SyncFrameInfo parseAc3SyncframeInfo(ParsableBitArray data) {
         sampleRate = SAMPLE_RATE_BY_FSCOD[fscod];
       }
       sampleCount = AUDIO_SAMPLES_PER_AUDIO_BLOCK * audioBlocks;
+      bitrate = calculateEac3Bitrate(frameSize, sampleRate, audioBlocks);
       acmod = data.readBits(3);
       lfeon = data.readBit();
       channelCount = CHANNEL_COUNT_BY_ACMOD[acmod] + (lfeon ? 1 : 0);
@@ -446,6 +452,7 @@ public static SyncFrameInfo parseAc3SyncframeInfo(ParsableBitArray data) {
         mimeType = null;
       }
       int frmsizecod = data.readBits(6);
+      bitrate = BITRATE_BY_HALF_FRMSIZECOD[frmsizecod / 2] * 1000;
       frameSize = getAc3SyncframeSize(fscod, frmsizecod);
       data.skipBits(5 + 3); // bsid, bsmod
       acmod = data.readBits(3);
@@ -465,7 +472,7 @@ public static SyncFrameInfo parseAc3SyncframeInfo(ParsableBitArray data) {
       channelCount = CHANNEL_COUNT_BY_ACMOD[acmod] + (lfeon ? 1 : 0);
     }
     return new SyncFrameInfo(
-        mimeType, streamType, channelCount, sampleRate, frameSize, sampleCount);
+        mimeType, streamType, channelCount, sampleRate, frameSize, sampleCount, bitrate);
   }
 
   /**
@@ -587,5 +594,15 @@ private static int getAc3SyncframeSize(int fscod, int frmsizecod) {
     }
   }
 
+  /**
+   * Derived from the formula defined in F.6.2.2 to calculate data_rate for the (E-)AC3 bitstream.
+   * Note: The formula is based on frmsiz read from the spec. We already do some modifications to it
+   * when deriving frameSize from the read value. The formula used here is adapted to accommodate
+   * that modification.
+   */
+  private static int calculateEac3Bitrate(int frameSize, int sampleRate, int audioBlocks) {
+    return (frameSize * sampleRate) / (audioBlocks * 32);
+  }
+
   private Ac3Util() {}
 }
diff --git a/library/extractor/src/main/java/com/google/android/exoplayer2/extractor/ts/Ac3Reader.java b/library/extractor/src/main/java/com/google/android/exoplayer2/extractor/ts/Ac3Reader.java
@@ -28,6 +28,7 @@
 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 com.google.android.exoplayer2.util.Util;
@@ -207,14 +208,19 @@ private void parseHeader() {
         || frameInfo.channelCount != format.channelCount
         || frameInfo.sampleRate != format.sampleRate
         || !Util.areEqual(frameInfo.mimeType, format.sampleMimeType)) {
-      format =
+      Format.Builder formatBuilder =
           new Format.Builder()
               .setId(formatId)
               .setSampleMimeType(frameInfo.mimeType)
               .setChannelCount(frameInfo.channelCount)
               .setSampleRate(frameInfo.sampleRate)
               .setLanguage(language)
-              .build();
+              .setPeakBitrate(frameInfo.bitrate);
+      // AC3 has constant bitrate, so averageBitrate = peakBitrate
+      if (MimeTypes.AUDIO_AC3.equals(frameInfo.mimeType)) {
+        formatBuilder.setAverageBitrate(frameInfo.bitrate);
+      }
+      format = formatBuilder.build();
       output.format(format);
     }
     sampleSize = frameInfo.frameSize;

diff --git a/testdata/src/test/assets/extractordumps/ts/sample.ac3.0.dump b/testdata/src/test/assets/extractordumps/ts/sample.ac3.0.dump
@@ -7,6 +7,8 @@ track 0:
   total output bytes = 13281
   sample count = 8
   format 0:
+    averageBitrate = 384000
+    peakBitrate = 384000
     id = 0
     sampleMimeType = audio/ac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample.ac3.unknown_length.dump b/testdata/src/test/assets/extractordumps/ts/sample.ac3.unknown_length.dump
@@ -7,6 +7,8 @@ track 0:
   total output bytes = 13281
   sample count = 8
   format 0:
+    averageBitrate = 384000
+    peakBitrate = 384000
     id = 0
     sampleMimeType = audio/ac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample.eac3.0.dump b/testdata/src/test/assets/extractordumps/ts/sample.eac3.0.dump
@@ -7,6 +7,7 @@ track 0:
   total output bytes = 216000
   sample count = 54
   format 0:
+    peakBitrate = 6000000
     id = 0
     sampleMimeType = audio/eac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample.eac3.unknown_length.dump b/testdata/src/test/assets/extractordumps/ts/sample.eac3.unknown_length.dump
@@ -7,6 +7,7 @@ track 0:
   total output bytes = 216000
   sample count = 54
   format 0:
+    peakBitrate = 6000000
     id = 0
     sampleMimeType = audio/eac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_ac3.ps.0.dump b/testdata/src/test/assets/extractordumps/ts/sample_ac3.ps.0.dump
@@ -10,6 +10,8 @@ track 189:
   total output bytes = 1252
   sample count = 3
   format 0:
+    averageBitrate = 96000
+    peakBitrate = 96000
     id = 189
     sampleMimeType = audio/ac3
     channelCount = 1

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_ac3.ps.unknown_length.dump b/testdata/src/test/assets/extractordumps/ts/sample_ac3.ps.unknown_length.dump
@@ -7,6 +7,8 @@ track 189:
   total output bytes = 1252
   sample count = 3
   format 0:
+    averageBitrate = 96000
+    peakBitrate = 96000
     id = 189
     sampleMimeType = audio/ac3
     channelCount = 1

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_ac3.ts.0.dump b/testdata/src/test/assets/extractordumps/ts/sample_ac3.ts.0.dump
@@ -10,6 +10,8 @@ track 1900:
   total output bytes = 13281
   sample count = 8
   format 0:
+    averageBitrate = 384000
+    peakBitrate = 384000
     id = 1/1900
     sampleMimeType = audio/ac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_ac3.ts.1.dump b/testdata/src/test/assets/extractordumps/ts/sample_ac3.ts.1.dump
@@ -10,6 +10,8 @@ track 1900:
   total output bytes = 10209
   sample count = 6
   format 0:
+    averageBitrate = 384000
+    peakBitrate = 384000
     id = 1/1900
     sampleMimeType = audio/ac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_ac3.ts.2.dump b/testdata/src/test/assets/extractordumps/ts/sample_ac3.ts.2.dump
@@ -10,6 +10,8 @@ track 1900:
   total output bytes = 7137
   sample count = 4
   format 0:
+    averageBitrate = 384000
+    peakBitrate = 384000
     id = 1/1900
     sampleMimeType = audio/ac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_ac3.ts.3.dump b/testdata/src/test/assets/extractordumps/ts/sample_ac3.ts.3.dump
@@ -10,6 +10,8 @@ track 1900:
   total output bytes = 0
   sample count = 0
   format 0:
+    averageBitrate = 384000
+    peakBitrate = 384000
     id = 1/1900
     sampleMimeType = audio/ac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_ac3.ts.unknown_length.dump b/testdata/src/test/assets/extractordumps/ts/sample_ac3.ts.unknown_length.dump
@@ -7,6 +7,8 @@ track 1900:
   total output bytes = 13281
   sample count = 8
   format 0:
+    averageBitrate = 384000
+    peakBitrate = 384000
     id = 1/1900
     sampleMimeType = audio/ac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_ait.ts.0.dump b/testdata/src/test/assets/extractordumps/ts/sample_ait.ts.0.dump
@@ -7,6 +7,7 @@ track 330:
   total output bytes = 9928
   sample count = 19
   format 0:
+    peakBitrate = 128000
     id = 1031/330
     sampleMimeType = audio/eac3
     channelCount = 2

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_ait.ts.unknown_length.dump b/testdata/src/test/assets/extractordumps/ts/sample_ait.ts.unknown_length.dump
@@ -7,6 +7,7 @@ track 330:
   total output bytes = 9928
   sample count = 19
   format 0:
+    peakBitrate = 128000
     id = 1031/330
     sampleMimeType = audio/eac3
     channelCount = 2

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_eac3.ts.0.dump b/testdata/src/test/assets/extractordumps/ts/sample_eac3.ts.0.dump
@@ -10,6 +10,7 @@ track 1900:
   total output bytes = 216000
   sample count = 54
   format 0:
+    peakBitrate = 6000000
     id = 1/1900
     sampleMimeType = audio/eac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_eac3.ts.1.dump b/testdata/src/test/assets/extractordumps/ts/sample_eac3.ts.1.dump
@@ -10,6 +10,7 @@ track 1900:
   total output bytes = 168000
   sample count = 42
   format 0:
+    peakBitrate = 6000000
     id = 1/1900
     sampleMimeType = audio/eac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_eac3.ts.2.dump b/testdata/src/test/assets/extractordumps/ts/sample_eac3.ts.2.dump
@@ -10,6 +10,7 @@ track 1900:
   total output bytes = 96000
   sample count = 24
   format 0:
+    peakBitrate = 6000000
     id = 1/1900
     sampleMimeType = audio/eac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_eac3.ts.3.dump b/testdata/src/test/assets/extractordumps/ts/sample_eac3.ts.3.dump
@@ -10,6 +10,7 @@ track 1900:
   total output bytes = 0
   sample count = 0
   format 0:
+    peakBitrate = 6000000
     id = 1/1900
     sampleMimeType = audio/eac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_eac3.ts.unknown_length.dump b/testdata/src/test/assets/extractordumps/ts/sample_eac3.ts.unknown_length.dump
@@ -7,6 +7,7 @@ track 1900:
   total output bytes = 216000
   sample count = 54
   format 0:
+    peakBitrate = 6000000
     id = 1/1900
     sampleMimeType = audio/eac3
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ec3.0.dump b/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ec3.0.dump
@@ -7,6 +7,7 @@ track 0:
   total output bytes = 163840
   sample count = 64
   format 0:
+    peakBitrate = 640000
     id = 0
     sampleMimeType = audio/eac3-joc
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ec3.unknown_length.dump b/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ec3.unknown_length.dump
@@ -7,6 +7,7 @@ track 0:
   total output bytes = 163840
   sample count = 64
   format 0:
+    peakBitrate = 640000
     id = 0
     sampleMimeType = audio/eac3-joc
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ts.0.dump b/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ts.0.dump
@@ -10,6 +10,7 @@ track 1900:
   total output bytes = 163840
   sample count = 64
   format 0:
+    peakBitrate = 640000
     id = 1/1900
     sampleMimeType = audio/eac3-joc
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ts.1.dump b/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ts.1.dump
@@ -10,6 +10,7 @@ track 1900:
   total output bytes = 112640
   sample count = 44
   format 0:
+    peakBitrate = 640000
     id = 1/1900
     sampleMimeType = audio/eac3-joc
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ts.2.dump b/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ts.2.dump
@@ -10,6 +10,7 @@ track 1900:
   total output bytes = 56320
   sample count = 22
   format 0:
+    peakBitrate = 640000
     id = 1/1900
     sampleMimeType = audio/eac3-joc
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ts.3.dump b/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ts.3.dump
@@ -10,6 +10,7 @@ track 1900:
   total output bytes = 5120
   sample count = 2
   format 0:
+    peakBitrate = 640000
     id = 1/1900
     sampleMimeType = audio/eac3-joc
     channelCount = 6

diff --git a/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ts.unknown_length.dump b/testdata/src/test/assets/extractordumps/ts/sample_eac3joc.ts.unknown_length.dump
@@ -7,6 +7,7 @@ track 1900:
   total output bytes = 163840
   sample count = 64
   format 0:
+    peakBitrate = 640000
     id = 1/1900
     sampleMimeType = audio/eac3-joc
     channelCount = 6