Derive average bitrate from stsz sample size and mdhd duration

Compute a precise average bitrate using total sample size (from `stsz`) and media duration (from `mdhd`), overriding any existing bitrate read from `btrt` or `esds` boxes.

PiperOrigin-RevId: 746497934
(cherry picked from commit 6f59827)

Author: rohitjoins

libraries/extractor/src/main/java/androidx/media3/extractor/mp4/BoxParser.java

@@ -55,6 +55,7 @@
 import com.google.common.base.Function;
 import com.google.common.collect.ImmutableList;
 import com.google.common.primitives.Ints;
+import java.math.RoundingMode;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.util.ArrayList;
@@ -527,6 +528,7 @@ public static TrackSampleTable parseStbl(
     int[] flags;
     long timestampTimeUnits = 0;
     long duration;
+    long totalSize = 0;
 
     if (rechunkFixedSizeSamples) {
       long[] chunkOffsetsBytes = new long[chunkIterator.length];
@@ -544,6 +546,7 @@ public static TrackSampleTable parseStbl(
       timestamps = rechunkedResults.timestamps;
       flags = rechunkedResults.flags;
       duration = rechunkedResults.duration;
+      totalSize = rechunkedResults.totalSize;
     } else {
       offsets = new long[sampleCount];
       sizes = new int[sampleCount];
@@ -586,6 +589,7 @@ public static TrackSampleTable parseStbl(
 
         offsets[i] = offset;
         sizes[i] = sampleSizeBox.readNextSampleSize();
+        totalSize += sizes[i];
         if (sizes[i] > maximumSize) {
           maximumSize = sizes[i];
         }
@@ -657,6 +661,20 @@ public static TrackSampleTable parseStbl(
                 + (!isCttsValid ? ", ctts invalid" : ""));
       }
     }
+
+    if (track.mediaDurationUs > 0) {
+      long averageBitrate =
+          Util.scaleLargeValue(
+              totalSize * C.BITS_PER_BYTE,
+              C.MICROS_PER_SECOND,
+              track.mediaDurationUs,
+              RoundingMode.HALF_DOWN);
+      if (averageBitrate > 0 && averageBitrate < Integer.MAX_VALUE) {
+        Format format = track.format.buildUpon().setAverageBitrate((int) averageBitrate).build();
+        track = track.copyWithFormat(format);
+      }
+    }
+
     long durationUs = Util.scaleLargeTimestamp(duration, C.MICROS_PER_SECOND, track.timescale);
 
     if (track.editListDurations == null) {

libraries/extractor/src/main/java/androidx/media3/extractor/mp4/FixedSampleSizeRechunker.java

@@ -35,20 +35,23 @@ public static final class Results {
     public final long[] timestamps;
     public final int[] flags;
     public final long duration;
+    public final long totalSize;
 
     private Results(
         long[] offsets,
         int[] sizes,
         int maximumSize,
         long[] timestamps,
         int[] flags,
-        long duration) {
+        long duration,
+        long totalSize) {
       this.offsets = offsets;
       this.sizes = sizes;
       this.maximumSize = maximumSize;
       this.timestamps = timestamps;
       this.flags = flags;
       this.duration = duration;
+      this.totalSize = totalSize;
     }
   }
 
@@ -81,6 +84,7 @@ public static Results rechunk(
     int maximumSize = 0;
     long[] timestamps = new long[rechunkedSampleCount];
     int[] flags = new int[rechunkedSampleCount];
+    int totalSize = 0;
 
     int originalSampleIndex = 0;
     int newSampleIndex = 0;
@@ -93,6 +97,7 @@ public static Results rechunk(
 
         offsets[newSampleIndex] = sampleOffset;
         sizes[newSampleIndex] = fixedSampleSize * bufferSampleCount;
+        totalSize += sizes[newSampleIndex];
         maximumSize = max(maximumSize, sizes[newSampleIndex]);
         timestamps[newSampleIndex] = (timestampDeltaInTimeUnits * originalSampleIndex);
         flags[newSampleIndex] = C.BUFFER_FLAG_KEY_FRAME;
@@ -106,7 +111,7 @@ public static Results rechunk(
     }
     long duration = timestampDeltaInTimeUnits * originalSampleIndex;
 
-    return new Results(offsets, sizes, maximumSize, timestamps, flags, duration);
+    return new Results(offsets, sizes, maximumSize, timestamps, flags, duration, totalSize);
   }
 
   private FixedSampleSizeRechunker() {

libraries/test_data/src/test/assets/extractordumps/jpeg/pixel-motion-photo-2-hevc-tracks.jpg.0.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 58
   track duration = 2100700
   format 0:
+    averageBitrate = 12593505
     id = 1
     containerMimeType = video/mp4
     sampleMimeType = video/hevc
@@ -269,6 +270,7 @@ track 1:
   sample count = 1
   track duration = 466800
   format 0:
+    averageBitrate = 2593047
     id = 2
     containerMimeType = video/mp4
     sampleMimeType = video/hevc
@@ -299,6 +301,7 @@ track 2:
   sample count = 58
   track duration = 2100700
   format 0:
+    averageBitrate = 99395
     id = 3
     containerMimeType = video/mp4
     sampleMimeType = application/microvideo-meta-stream
@@ -541,6 +544,7 @@ track 3:
   sample count = 1
   track duration = 1133700
   format 0:
+    averageBitrate = 416
     id = 4
     containerMimeType = video/mp4
     sampleMimeType = application/motionphoto-image-meta

libraries/test_data/src/test/assets/extractordumps/jpeg/pixel-motion-photo-2-hevc-tracks.jpg.1.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 44
   track duration = 2100700
   format 0:
+    averageBitrate = 12593505
     id = 1
     containerMimeType = video/mp4
     sampleMimeType = video/hevc
@@ -213,6 +214,7 @@ track 1:
   sample count = 1
   track duration = 466800
   format 0:
+    averageBitrate = 2593047
     id = 2
     containerMimeType = video/mp4
     sampleMimeType = video/hevc
@@ -243,6 +245,7 @@ track 2:
   sample count = 38
   track duration = 2100700
   format 0:
+    averageBitrate = 99395
     id = 3
     containerMimeType = video/mp4
     sampleMimeType = application/microvideo-meta-stream
@@ -405,6 +408,7 @@ track 3:
   sample count = 1
   track duration = 1133700
   format 0:
+    averageBitrate = 416
     id = 4
     containerMimeType = video/mp4
     sampleMimeType = application/motionphoto-image-meta

libraries/test_data/src/test/assets/extractordumps/jpeg/pixel-motion-photo-2-hevc-tracks.jpg.2.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 23
   track duration = 2100700
   format 0:
+    averageBitrate = 12593505
     id = 1
     containerMimeType = video/mp4
     sampleMimeType = video/hevc
@@ -129,6 +130,7 @@ track 1:
   sample count = 1
   track duration = 466800
   format 0:
+    averageBitrate = 2593047
     id = 2
     containerMimeType = video/mp4
     sampleMimeType = video/hevc
@@ -159,6 +161,7 @@ track 2:
   sample count = 17
   track duration = 2100700
   format 0:
+    averageBitrate = 99395
     id = 3
     containerMimeType = video/mp4
     sampleMimeType = application/microvideo-meta-stream
@@ -237,6 +240,7 @@ track 3:
   sample count = 1
   track duration = 1133700
   format 0:
+    averageBitrate = 416
     id = 4
     containerMimeType = video/mp4
     sampleMimeType = application/motionphoto-image-meta

libraries/test_data/src/test/assets/extractordumps/jpeg/pixel-motion-photo-2-hevc-tracks.jpg.3.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 2
   track duration = 2100700
   format 0:
+    averageBitrate = 12593505
     id = 1
     containerMimeType = video/mp4
     sampleMimeType = video/hevc
@@ -45,6 +46,7 @@ track 1:
   sample count = 1
   track duration = 466800
   format 0:
+    averageBitrate = 2593047
     id = 2
     containerMimeType = video/mp4
     sampleMimeType = video/hevc
@@ -75,6 +77,7 @@ track 2:
   sample count = 1
   track duration = 2100700
   format 0:
+    averageBitrate = 99395
     id = 3
     containerMimeType = video/mp4
     sampleMimeType = application/microvideo-meta-stream
@@ -89,6 +92,7 @@ track 3:
   sample count = 1
   track duration = 1133700
   format 0:
+    averageBitrate = 416
     id = 4
     containerMimeType = video/mp4
     sampleMimeType = application/motionphoto-image-meta

libraries/test_data/src/test/assets/extractordumps/jpeg/pixel-motion-photo-jfif-segment-shortened.jpg.0.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 1
   track duration = 867000
   format 0:
+    averageBitrate = 35692
     id = 1
     containerMimeType = video/mp4
     sampleMimeType = video/avc

libraries/test_data/src/test/assets/extractordumps/jpeg/pixel-motion-photo-jfif-segment-shortened.jpg.1.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 1
   track duration = 867000
   format 0:
+    averageBitrate = 35692
     id = 1
     containerMimeType = video/mp4
     sampleMimeType = video/avc

libraries/test_data/src/test/assets/extractordumps/jpeg/pixel-motion-photo-jfif-segment-shortened.jpg.2.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 1
   track duration = 867000
   format 0:
+    averageBitrate = 35692
     id = 1
     containerMimeType = video/mp4
     sampleMimeType = video/avc

libraries/test_data/src/test/assets/extractordumps/jpeg/pixel-motion-photo-jfif-segment-shortened.jpg.3.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 1
   track duration = 867000
   format 0:
+    averageBitrate = 35692
     id = 1
     containerMimeType = video/mp4
     sampleMimeType = video/avc

libraries/test_data/src/test/assets/extractordumps/mp4/bt601.mov.0.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 43
   track duration = 1019300
   format 0:
+    averageBitrate = 74502
     peakBitrate = 200000
     id = 1
     containerMimeType = video/mp4
@@ -200,6 +201,7 @@ track 1:
   sample count = 30
   track duration = 1020100
   format 0:
+    averageBitrate = 1026770
     id = 2
     containerMimeType = video/mp4
     sampleMimeType = video/avc

libraries/test_data/src/test/assets/extractordumps/mp4/bt601.mov.1.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 31
   track duration = 1019300
   format 0:
+    averageBitrate = 74502
     peakBitrate = 200000
     id = 1
     containerMimeType = video/mp4
@@ -152,6 +153,7 @@ track 1:
   sample count = 30
   track duration = 1020100
   format 0:
+    averageBitrate = 1026770
     id = 2
     containerMimeType = video/mp4
     sampleMimeType = video/avc

libraries/test_data/src/test/assets/extractordumps/mp4/bt601.mov.2.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 16
   track duration = 1019300
   format 0:
+    averageBitrate = 74502
     peakBitrate = 200000
     id = 1
     containerMimeType = video/mp4
@@ -92,6 +93,7 @@ track 1:
   sample count = 30
   track duration = 1020100
   format 0:
+    averageBitrate = 1026770
     id = 2
     containerMimeType = video/mp4
     sampleMimeType = video/avc

libraries/test_data/src/test/assets/extractordumps/mp4/bt601.mov.3.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 1
   track duration = 1019300
   format 0:
+    averageBitrate = 74502
     peakBitrate = 200000
     id = 1
     containerMimeType = video/mp4
@@ -32,6 +33,7 @@ track 1:
   sample count = 30
   track duration = 1020100
   format 0:
+    averageBitrate = 1026770
     id = 2
     containerMimeType = video/mp4
     sampleMimeType = video/avc

libraries/test_data/src/test/assets/extractordumps/mp4/bt601.mov.reading_within_gop_sample_dependencies.0.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 43
   track duration = 1019300
   format 0:
+    averageBitrate = 74502
     peakBitrate = 200000
     id = 1
     containerMimeType = video/mp4
@@ -200,6 +201,7 @@ track 1:
   sample count = 30
   track duration = 1020100
   format 0:
+    averageBitrate = 1026770
     id = 2
     containerMimeType = video/mp4
     sampleMimeType = video/avc

libraries/test_data/src/test/assets/extractordumps/mp4/bt601.mov.reading_within_gop_sample_dependencies.1.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 31
   track duration = 1019300
   format 0:
+    averageBitrate = 74502
     peakBitrate = 200000
     id = 1
     containerMimeType = video/mp4
@@ -152,6 +153,7 @@ track 1:
   sample count = 30
   track duration = 1020100
   format 0:
+    averageBitrate = 1026770
     id = 2
     containerMimeType = video/mp4
     sampleMimeType = video/avc

libraries/test_data/src/test/assets/extractordumps/mp4/bt601.mov.reading_within_gop_sample_dependencies.2.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 16
   track duration = 1019300
   format 0:
+    averageBitrate = 74502
     peakBitrate = 200000
     id = 1
     containerMimeType = video/mp4
@@ -92,6 +93,7 @@ track 1:
   sample count = 30
   track duration = 1020100
   format 0:
+    averageBitrate = 1026770
     id = 2
     containerMimeType = video/mp4
     sampleMimeType = video/avc

libraries/test_data/src/test/assets/extractordumps/mp4/bt601.mov.reading_within_gop_sample_dependencies.3.dump

@@ -11,6 +11,7 @@ track 0:
   sample count = 1
   track duration = 1019300
   format 0:
+    averageBitrate = 74502
     peakBitrate = 200000
     id = 1
     containerMimeType = video/mp4
@@ -32,6 +33,7 @@ track 1:
   sample count = 30
   track duration = 1020100
   format 0:
+    averageBitrate = 1026770
     id = 2
     containerMimeType = video/mp4
     sampleMimeType = video/avc