DASH: Avoid rounding error in getSegmentCount

Issue: #8804
PiperOrigin-RevId: 369484117

RELEASENOTES.md

@@ -142,6 +142,10 @@
 *   DASH:
     *   Parse `forced_subtitle` role from DASH manifests
         ([#8781](https://github.com/google/ExoPlayer/issues/8781)).
+*   DASH:
+    *   Fix rounding error that could cause `SegmentTemplate.getSegmentCount()`
+        to return incorrect values
+        ([#8804](https://github.com/google/ExoPlayer/issues/8804)).
 *   HLS:
     *   Fix bug of ignoring `EXT-X-START` when setting the live target offset
         ([#8764](https://github.com/google/ExoPlayer/pull/8764)).

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaSource.java

@@ -1139,7 +1139,7 @@ public final class DashMediaSource extends BaseMediaSource {
       if (index == null) {
         return periodStartTimeInManifestUs;
       }
-      int availableSegmentCount = index.getAvailableSegmentCount(periodDurationUs, nowUnixTimeUs);
+      long availableSegmentCount = index.getAvailableSegmentCount(periodDurationUs, nowUnixTimeUs);
       if (availableSegmentCount == 0) {
         return periodStartTimeInManifestUs;
       }
@@ -1171,7 +1171,7 @@ public final class DashMediaSource extends BaseMediaSource {
       if (index == null) {
         return periodStartTimeInManifestUs + periodDurationUs;
       }
-      int availableSegmentCount = index.getAvailableSegmentCount(periodDurationUs, nowUnixTimeUs);
+      long availableSegmentCount = index.getAvailableSegmentCount(periodDurationUs, nowUnixTimeUs);
       if (availableSegmentCount == 0) {
         return periodStartTimeInManifestUs;
       }

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashSegmentIndex.java

@@ -89,7 +89,7 @@ public interface DashSegmentIndex {
    *     C#TIME_UNSET} if the period's duration is not yet known.
    * @return The number of segments in the index, or {@link #INDEX_UNBOUNDED}.
    */
-  int getSegmentCount(long periodDurationUs);
+  long getSegmentCount(long periodDurationUs);
 
   /**
    * Returns the number of available segments in the index.
@@ -99,7 +99,7 @@ public interface DashSegmentIndex {
    * @param nowUnixTimeUs The current time in milliseconds since the Unix epoch.
    * @return The number of available segments in the index.
    */
-  int getAvailableSegmentCount(long periodDurationUs, long nowUnixTimeUs);
+  long getAvailableSegmentCount(long periodDurationUs, long nowUnixTimeUs);
 
   /**
    * Returns the time, in microseconds, at which a new segment becomes available, or {@link

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashWrappingSegmentIndex.java

@@ -48,12 +48,12 @@ public final class DashWrappingSegmentIndex implements DashSegmentIndex {
   }
 
   @Override
-  public int getSegmentCount(long periodDurationUs) {
+  public long getSegmentCount(long periodDurationUs) {
     return chunkIndex.length;
   }
 
   @Override
-  public int getAvailableSegmentCount(long periodDurationUs, long nowUnixTimeUs) {
+  public long getAvailableSegmentCount(long periodDurationUs, long nowUnixTimeUs) {
     return chunkIndex.length;
   }
 

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DefaultDashChunkSource.java

@@ -222,7 +222,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
       if (representationHolder.segmentIndex != null) {
         long segmentNum = representationHolder.getSegmentNum(positionUs);
         long firstSyncUs = representationHolder.getSegmentStartTimeUs(segmentNum);
-        int segmentCount = representationHolder.getSegmentCount();
+        long segmentCount = representationHolder.getSegmentCount();
         long secondSyncUs =
             firstSyncUs < positionUs
                     && (segmentCount == DashSegmentIndex.INDEX_UNBOUNDED
@@ -465,7 +465,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
         && ((InvalidResponseCodeException) e).responseCode == 404) {
       RepresentationHolder representationHolder =
           representationHolders[trackSelection.indexOf(chunk.trackFormat)];
-      int segmentCount = representationHolder.getSegmentCount();
+      long segmentCount = representationHolder.getSegmentCount();
       if (segmentCount != DashSegmentIndex.INDEX_UNBOUNDED && segmentCount != 0) {
         long lastAvailableSegmentNum = representationHolder.getFirstSegmentNum() + segmentCount - 1;
         if (((MediaChunk) chunk).getNextChunkIndex() > lastAvailableSegmentNum) {
@@ -723,7 +723,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
             newPeriodDurationUs, newRepresentation, chunkExtractor, segmentNumShift, newIndex);
       }
 
-      int oldIndexSegmentCount = oldIndex.getSegmentCount(newPeriodDurationUs);
+      long oldIndexSegmentCount = oldIndex.getSegmentCount(newPeriodDurationUs);
       if (oldIndexSegmentCount == 0) {
         // Segment numbers cannot shift if the old index was empty.
         return new RepresentationHolder(
@@ -777,7 +777,7 @@ public class DefaultDashChunkSource implements DashChunkSource {
           + segmentNumShift;
     }
 
-    public int getSegmentCount() {
+    public long getSegmentCount() {
       return segmentIndex.getSegmentCount(periodDurationUs);
     }
 

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/Representation.java

@@ -352,12 +352,12 @@ public abstract class Representation {
     }
 
     @Override
-    public int getSegmentCount(long periodDurationUs) {
+    public long getSegmentCount(long periodDurationUs) {
       return segmentBase.getSegmentCount(periodDurationUs);
     }
 
     @Override
-    public int getAvailableSegmentCount(long periodDurationUs, long nowUnixTimeUs) {
+    public long getAvailableSegmentCount(long periodDurationUs, long nowUnixTimeUs) {
       return segmentBase.getAvailableSegmentCount(periodDurationUs, nowUnixTimeUs);
     }
 

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/SegmentBase.java

@@ -24,6 +24,9 @@ import androidx.annotation.VisibleForTesting;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.source.dash.DashSegmentIndex;
 import com.google.android.exoplayer2.util.Util;
+import com.google.common.math.BigIntegerMath;
+import java.math.BigInteger;
+import java.math.RoundingMode;
 import java.util.List;
 
 /**
@@ -214,7 +217,7 @@ public abstract class SegmentBase {
         long duration = segmentTimeline.get((int) (sequenceNumber - startNumber)).duration;
         return (duration * C.MICROS_PER_SECOND) / timescale;
       } else {
-        int segmentCount = getSegmentCount(periodDurationUs);
+        long segmentCount = getSegmentCount(periodDurationUs);
         return segmentCount != INDEX_UNBOUNDED
                 && sequenceNumber == (getFirstSegmentNum() + segmentCount - 1)
             ? (periodDurationUs - getSegmentTimeUs(sequenceNumber))
@@ -264,8 +267,8 @@ public abstract class SegmentBase {
     }
 
     /** See {@link DashSegmentIndex#getAvailableSegmentCount(long, long)}. */
-    public int getAvailableSegmentCount(long periodDurationUs, long nowUnixTimeUs) {
-      int segmentCount = getSegmentCount(periodDurationUs);
+    public long getAvailableSegmentCount(long periodDurationUs, long nowUnixTimeUs) {
+      long segmentCount = getSegmentCount(periodDurationUs);
       if (segmentCount != INDEX_UNBOUNDED) {
         return segmentCount;
       }
@@ -298,7 +301,7 @@ public abstract class SegmentBase {
     }
 
     /** See {@link DashSegmentIndex#getSegmentCount(long)}. */
-    public abstract int getSegmentCount(long periodDurationUs);
+    public abstract long getSegmentCount(long periodDurationUs);
   }
 
   /** A {@link MultiSegmentBase} that uses a SegmentList to define its segments. */
@@ -356,7 +359,7 @@ public abstract class SegmentBase {
     }
 
     @Override
-    public int getSegmentCount(long periodDurationUs) {
+    public long getSegmentCount(long periodDurationUs) {
       return mediaSegments.size();
     }
 
@@ -455,14 +458,17 @@ public abstract class SegmentBase {
     }
 
     @Override
-    public int getSegmentCount(long periodDurationUs) {
+    public long getSegmentCount(long periodDurationUs) {
       if (segmentTimeline != null) {
         return segmentTimeline.size();
       } else if (endNumber != C.INDEX_UNSET) {
-        return (int) (endNumber - startNumber + 1);
+        return endNumber - startNumber + 1;
       } else if (periodDurationUs != C.TIME_UNSET) {
-        long durationUs = (duration * C.MICROS_PER_SECOND) / timescale;
-        return (int) Util.ceilDivide(periodDurationUs, durationUs);
+        BigInteger numerator =
+            BigInteger.valueOf(periodDurationUs).multiply(BigInteger.valueOf(timescale));
+        BigInteger denominator =
+            BigInteger.valueOf(duration).multiply(BigInteger.valueOf(C.MICROS_PER_SECOND));
+        return BigIntegerMath.divide(numerator, denominator, RoundingMode.CEILING).longValue();
       } else {
         return INDEX_UNBOUNDED;
       }

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/SingleSegmentIndex.java

@@ -63,12 +63,12 @@ import com.google.android.exoplayer2.source.dash.DashSegmentIndex;
   }
 
   @Override
-  public int getSegmentCount(long periodDurationUs) {
+  public long getSegmentCount(long periodDurationUs) {
     return 1;
   }
 
   @Override
-  public int getAvailableSegmentCount(long periodDurationUs, long nowUnixTimeUs) {
+  public long getAvailableSegmentCount(long periodDurationUs, long nowUnixTimeUs) {
     return 1;
   }
 

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/offline/DashDownloader.java

@@ -183,7 +183,7 @@ public final class DashDownloader extends SegmentDownloader<DashManifest> {
         continue;
       }
 
-      int segmentCount = index.getSegmentCount(periodDurationUs);
+      long segmentCount = index.getSegmentCount(periodDurationUs);
       if (segmentCount == DashSegmentIndex.INDEX_UNBOUNDED) {
         throw new DownloadException("Unbounded segment index");
       }

library/dash/src/test/java/com/google/android/exoplayer2/source/dash/manifest/SegmentBaseTest.java

@@ -182,4 +182,43 @@ public final class SegmentBaseTest {
                 /* nowUnixTimeUs= */ periodStartUnixTimeUs + 17_500_000))
         .isEqualTo(19_500_000);
   }
+
+  /** Regression test for https://github.com/google/ExoPlayer/issues/8804. */
+  @Test
+  public void getSegmentCount_withSegmentTemplate_avoidsIncorrectRounding() {
+    SegmentBase.SegmentTemplate segmentTemplate =
+        new SegmentBase.SegmentTemplate(
+            /* initialization= */ null,
+            /* timescale= */ 90000,
+            /* presentationTimeOffset= */ 0,
+            /* startNumber= */ 0,
+            /* endNumber= */ C.INDEX_UNSET,
+            /* duration= */ 179989,
+            /* segmentTimeline= */ null,
+            /* availabilityTimeOffsetUs= */ C.TIME_UNSET,
+            /* initializationTemplate= */ null,
+            /* mediaTemplate= */ null,
+            /* timeShiftBufferDepthUs= */ C.TIME_UNSET,
+            /* periodStartUnixTimeUs= */ C.TIME_UNSET);
+    assertThat(segmentTemplate.getSegmentCount(2931820000L)).isEqualTo(1466);
+  }
+
+  @Test
+  public void getSegmentCount_withSegmentTemplate_avoidsOverflow() {
+    SegmentBase.SegmentTemplate segmentTemplate =
+        new SegmentBase.SegmentTemplate(
+            /* initialization= */ null,
+            /* timescale= */ 1000000,
+            /* presentationTimeOffset= */ 0,
+            /* startNumber= */ 0,
+            /* endNumber= */ C.INDEX_UNSET,
+            /* duration= */ 179989,
+            /* segmentTimeline= */ null,
+            /* availabilityTimeOffsetUs= */ C.TIME_UNSET,
+            /* initializationTemplate= */ null,
+            /* mediaTemplate= */ null,
+            /* timeShiftBufferDepthUs= */ C.TIME_UNSET,
+            /* periodStartUnixTimeUs= */ C.TIME_UNSET);
+    assertThat(segmentTemplate.getSegmentCount(1618875028000000L)).isEqualTo(8994299808L);
+  }
 }