Update Boxes to support writing negative timestamps to edit list

Previously when there were negative timestamps, the tkhd duration was incorrectly equal to the full track duration rather than the presentation duration of the edit list. From the [docs](https://developer.apple.com/documentation/quicktime-file-format/track_header_atom/duration) - "The value of this field is equal to the sum of the durations of all of the track’s edits".

PiperOrigin-RevId: 752655137

libraries/muxer/src/main/java/androidx/media3/muxer/Boxes.java

@@ -162,7 +162,8 @@ import org.checkerframework.checker.nullness.qual.PolyNull;
       }
       String languageCode = bcp47LanguageTagToIso3(format.language);
 
-      // Generate the sample durations to calculate the total duration for tkhd box.
+      // Generate the sample durations to calculate the total duration for tkhd, elst and mvhd
+      // boxes.
       List<Integer> sampleDurationsVu =
           convertPresentationTimestampsToDurationsVu(
               track.writtenSamples,
@@ -178,6 +179,8 @@ import org.checkerframework.checker.nullness.qual.PolyNull;
       long firstInputPtsUs =
           track.writtenSamples.isEmpty() ? 0 : track.writtenSamples.get(0).presentationTimeUs;
       long trackDurationUs = usFromVu(trackDurationInTrackUnitsVu, track.videoUnitTimebase());
+      long presentationTrackDurationUs =
+          firstInputPtsUs < 0 ? trackDurationUs - abs(firstInputPtsUs) : trackDurationUs;
 
       @C.TrackType int trackType = MimeTypes.getTrackType(format.sampleMimeType);
       ByteBuffer stts = stts(sampleDurationsVu);
@@ -232,7 +235,7 @@ import org.checkerframework.checker.nullness.qual.PolyNull;
           trak(
               tkhd(
                   nextTrackId,
-                  trackDurationUs,
+                  presentationTrackDurationUs,
                   creationTimestampSeconds,
                   modificationTimestampSeconds,
                   metadataCollector.orientationData.orientation,
@@ -240,7 +243,7 @@ import org.checkerframework.checker.nullness.qual.PolyNull;
               edts(
                   firstInputPtsUs,
                   minInputPtsUs,
-                  trackDurationUs,
+                  presentationTrackDurationUs,
                   MVHD_TIMEBASE,
                   track.videoUnitTimebase()),
               mdia(
@@ -254,7 +257,7 @@ import org.checkerframework.checker.nullness.qual.PolyNull;
                   minf(mhdBox, dinf(dref(localUrl())), stblBox)));
 
       trakBoxes.add(trakBox);
-      videoDurationUs = max(videoDurationUs, trackDurationUs);
+      videoDurationUs = max(videoDurationUs, presentationTrackDurationUs);
       trexBoxes.add(trex(nextTrackId));
       nextTrackId++;
     }
@@ -853,8 +856,7 @@ import org.checkerframework.checker.nullness.qual.PolyNull;
       elstContent.putInt(1); // Entry count
       elstContent.put(
           elstEntry(
-              /* editDurationVu= */ vuFromUs(
+              /* editDurationVu= */ vuFromUs(trackDurationUs, mvhdTimescale),
-                  trackDurationUs - abs(firstSamplePtsUs), mvhdTimescale),
               /* mediaTimeVu= */ vuFromUs(abs(firstSamplePtsUs), trackTimescale),
               /* mediaRateInt= */ 1,
               /* mediaRateFraction= */ 0));

libraries/muxer/src/test/java/androidx/media3/muxer/BoxesTest.java

@@ -593,6 +593,40 @@ public class BoxesTest {
     assertThat(durationsVu).containsExactly(100, 100, 800, 100, 0);
   }
 
+  @Test
+  public void
+      convertPresentationTimestampsToDurationsVu_withNegativeSampleTimestampsAndZero_returnsExpectedDurations() {
+    List<BufferInfo> sampleBufferInfos =
+        createBufferInfoListWithSamplePresentationTimestamps(
+            -1_000L, 0L, 10_000L, 1_000L, 2_000L, 11_000L);
+
+    List<Integer> durationsVu =
+        Boxes.convertPresentationTimestampsToDurationsVu(
+            sampleBufferInfos,
+            VU_TIMEBASE,
+            LAST_SAMPLE_DURATION_BEHAVIOR_SET_TO_ZERO,
+            C.TIME_UNSET);
+
+    assertThat(durationsVu).containsExactly(100, 100, 100, 800, 100, 0);
+  }
+
+  @Test
+  public void
+      convertPresentationTimestampsToDurationsVu_withNegativeSampleTimestamps_returnsExpectedDurations() {
+    List<BufferInfo> sampleBufferInfos =
+        createBufferInfoListWithSamplePresentationTimestamps(
+            -1_000L, 10_000L, 1_000L, 2_000L, 11_000L);
+
+    List<Integer> durationsVu =
+        Boxes.convertPresentationTimestampsToDurationsVu(
+            sampleBufferInfos,
+            VU_TIMEBASE,
+            LAST_SAMPLE_DURATION_BEHAVIOR_SET_TO_ZERO,
+            C.TIME_UNSET);
+
+    assertThat(durationsVu).containsExactly(200, 100, 800, 100, 0);
+  }
+
   @Test
   public void
       convertPresentationTimestampsToDurationsVu_withLastSampleDurationBehaviorUsingEndOfStreamFlag_returnsExpectedDurations() {

libraries/test_data/src/test/assets/muxerdumps/mp4_with_negative_tracks_offset.mp4.dump

@@ -1,15 +1,15 @@
 seekMap:
   isSeekable = true
-  duration = 600
+  duration = 500
   getPosition(0) = [[timeUs=-100, position=400052], [timeUs=100, position=400108]]
   getPosition(1) = [[timeUs=-100, position=400052], [timeUs=100, position=400108]]
-  getPosition(300) = [[timeUs=300, position=400164]]
+  getPosition(250) = [[timeUs=100, position=400108], [timeUs=300, position=400164]]
-  getPosition(600) = [[timeUs=300, position=400164]]
+  getPosition(500) = [[timeUs=300, position=400164]]
 numberOfTracks = 1
 track 0:
   total output bytes = 168
   sample count = 3
-  track duration = 600
+  track duration = 500
   format 0:
     averageBitrate = 2240000
     id = 1

libraries/test_data/src/test/assets/muxerdumps/negative_start_time_edts_box.dump

@@ -1,3 +1,3 @@
 edts (44 bytes):
   elst (36 bytes):
-    Data = length 28, hash 68F2D7C9
+    Data = length 28, hash 75FF2BCC

libraries/test_data/src/test/assets/muxerdumps/sample_edit_list.mp4.dump

@@ -1,15 +1,15 @@
 seekMap:
   isSeekable = true
-  duration = 3135000
+  duration = 2680000
   getPosition(0) = [[timeUs=-455000, position=400052], [timeUs=611666, position=411095]]
   getPosition(1) = [[timeUs=-455000, position=400052], [timeUs=611666, position=411095]]
-  getPosition(1567500) = [[timeUs=611666, position=411095], [timeUs=1680000, position=429829]]
+  getPosition(1340000) = [[timeUs=611666, position=411095], [timeUs=1680000, position=429829]]
-  getPosition(3135000) = [[timeUs=1680000, position=429829]]
+  getPosition(2680000) = [[timeUs=1680000, position=429829]]
 numberOfTracks = 3
 track 0:
   total output bytes = 3208515
   sample count = 85
-  track duration = 3135000
+  track duration = 2680000
   format 0:
     averageBitrate = 8187598
     id = 1
@@ -376,7 +376,7 @@ track 0:
 track 1:
   total output bytes = 3208515
   sample count = 85
-  track duration = 3135000
+  track duration = 2680000
   format 0:
     averageBitrate = 8187598
     id = 2

libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerEndToEndTest.java

@@ -2153,8 +2153,7 @@ public class TransformerEndToEndTest {
     Mp4Extractor mp4Extractor = new Mp4Extractor(new DefaultSubtitleParserFactory());
     FakeExtractorOutput fakeExtractorOutput =
         TestUtil.extractAllSamplesFromFilePath(mp4Extractor, exportTestResult.filePath);
-    // TODO: b/324903070 - The generated output file has incorrect duration.
+    assertThat(fakeExtractorOutput.seekMap.getDurationUs()).isEqualTo(1_562_800);
-    assertThat(fakeExtractorOutput.seekMap.getDurationUs()).isEqualTo(1_579_600);
     assertThat(fakeExtractorOutput.numberOfTracks).isEqualTo(1);
     FakeTrackOutput audioTrack = fakeExtractorOutput.trackOutputs.get(0);
     int expectedSampleCount = 68;