make merged segment size configurable

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/offline/SegmentDownloader.java

@@ -76,7 +76,7 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M>> impleme
   }
 
   private static final int BUFFER_SIZE_BYTES = 128 * 1024;
-  private static final long MAX_MERGED_SEGMENT_START_TIME_DIFF_US = 20 * C.MICROS_PER_SECOND;
+  public static final long DEFAULT_MAX_MERGED_SEGMENT_START_TIME_DIFF_US = 20 * C.MICROS_PER_SECOND;
 
   private final DataSpec manifestDataSpec;
   private final Parser<M> manifestParser;
@@ -86,6 +86,7 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M>> impleme
   private final CacheKeyFactory cacheKeyFactory;
   @Nullable private final PriorityTaskManager priorityTaskManager;
   private final Executor executor;
+  private final long maxMergedSegmentStartTimeDiffUs;
 
   /**
    * The currently active runnables.
@@ -100,19 +101,16 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M>> impleme
   private volatile boolean isCanceled;
 
   /**
-   * @param mediaItem The {@link MediaItem} to be downloaded.
+   * @deprecated Use {@link SegmentDownloader#SegmentDownloader(MediaItem, Parser,
-   * @param manifestParser A parser for manifests belonging to the media to be downloaded.
+   * CacheDataSource.Factory, Executor, long)} instead.
-   * @param cacheDataSourceFactory A {@link CacheDataSource.Factory} for the cache into which the
-   *     download will be written.
-   * @param executor An {@link Executor} used to make requests for the media being downloaded.
-   *     Providing an {@link Executor} that uses multiple threads will speed up the download by
-   *     allowing parts of it to be executed in parallel.
    */
+  @Deprecated
   public SegmentDownloader(
       MediaItem mediaItem,
       Parser<M> manifestParser,
       CacheDataSource.Factory cacheDataSourceFactory,
-      Executor executor) {
+      Executor executor
+  ) {
     checkNotNull(mediaItem.localConfiguration);
     this.manifestDataSpec = getCompressibleDataSpec(mediaItem.localConfiguration.uri);
     this.manifestParser = manifestParser;
@@ -123,6 +121,39 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M>> impleme
     cacheKeyFactory = cacheDataSourceFactory.getCacheKeyFactory();
     priorityTaskManager = cacheDataSourceFactory.getUpstreamPriorityTaskManager();
     activeRunnables = new ArrayList<>();
+    maxMergedSegmentStartTimeDiffUs = DEFAULT_MAX_MERGED_SEGMENT_START_TIME_DIFF_US;
+  }
+
+  /**
+   * @param mediaItem The {@link MediaItem} to be downloaded.
+   * @param manifestParser A parser for manifests belonging to the media to be downloaded.
+   * @param cacheDataSourceFactory A {@link CacheDataSource.Factory} for the cache into which the
+   *     download will be written.
+   * @param executor An {@link Executor} used to make requests for the media being downloaded.
+   *     Providing an {@link Executor} that uses multiple threads will speed up the download by
+   *     allowing parts of it to be executed in parallel.
+   * @param maxMergedSegmentStartTimeDiffMs The maximum difference of the start time of two segments,
+   *     up to which the segments (of the same URI) should be merged into a single download segment,
+   *     in milliseconds.
+   */
+  public SegmentDownloader(
+      MediaItem mediaItem,
+      Parser<M> manifestParser,
+      CacheDataSource.Factory cacheDataSourceFactory,
+      Executor executor,
+      long maxMergedSegmentStartTimeDiffMs
+  ) {
+    checkNotNull(mediaItem.localConfiguration);
+    this.manifestDataSpec = getCompressibleDataSpec(mediaItem.localConfiguration.uri);
+    this.manifestParser = manifestParser;
+    this.streamKeys = new ArrayList<>(mediaItem.localConfiguration.streamKeys);
+    this.cacheDataSourceFactory = cacheDataSourceFactory;
+    this.executor = executor;
+    cache = Assertions.checkNotNull(cacheDataSourceFactory.getCache());
+    cacheKeyFactory = cacheDataSourceFactory.getCacheKeyFactory();
+    priorityTaskManager = cacheDataSourceFactory.getUpstreamPriorityTaskManager();
+    activeRunnables = new ArrayList<>();
+    maxMergedSegmentStartTimeDiffUs = Util.msToUs(maxMergedSegmentStartTimeDiffMs);
   }
 
   @Override
@@ -145,7 +176,7 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M>> impleme
       // Sort the segments so that we download media in the right order from the start of the
       // content, and merge segments where possible to minimize the number of server round trips.
       Collections.sort(segments);
-      mergeSegments(segments, cacheKeyFactory);
+      mergeSegments(segments, cacheKeyFactory, maxMergedSegmentStartTimeDiffUs);
 
       // Scan the segments, removing any that are fully downloaded.
       int totalSegments = segments.size();
@@ -416,7 +447,11 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M>> impleme
     }
   }
 
-  private static void mergeSegments(List<Segment> segments, CacheKeyFactory keyFactory) {
+  private static void mergeSegments(
+      List<Segment> segments,
+      CacheKeyFactory keyFactory,
+      long maxMergedSegmentStartTimeDiffUs
+  ) {
     HashMap<String, Integer> lastIndexByCacheKey = new HashMap<>();
     int nextOutIndex = 0;
     for (int i = 0; i < segments.size(); i++) {
@@ -425,7 +460,7 @@ public abstract class SegmentDownloader<M extends FilterableManifest<M>> impleme
       @Nullable Integer lastIndex = lastIndexByCacheKey.get(cacheKey);
       @Nullable Segment lastSegment = lastIndex == null ? null : segments.get(lastIndex);
       if (lastSegment == null
-          || segment.startTimeUs > lastSegment.startTimeUs + MAX_MERGED_SEGMENT_START_TIME_DIFF_US
+          || segment.startTimeUs > lastSegment.startTimeUs + maxMergedSegmentStartTimeDiffUs
           || !canMergeSegments(lastSegment.dataSpec, segment.dataSpec)) {
         lastIndexByCacheKey.put(cacheKey, nextOutIndex);
         segments.set(nextOutIndex, segment);

libraries/exoplayer_dash/src/main/java/androidx/media3/exoplayer/dash/offline/DashDownloader.java

@@ -100,7 +100,28 @@ public final class DashDownloader extends SegmentDownloader<DashManifest> {
    */
   public DashDownloader(
       MediaItem mediaItem, CacheDataSource.Factory cacheDataSourceFactory, Executor executor) {
-    this(mediaItem, new DashManifestParser(), cacheDataSourceFactory, executor);
+    this(mediaItem, new DashManifestParser(), cacheDataSourceFactory, executor, DEFAULT_MAX_MERGED_SEGMENT_START_TIME_DIFF_US);
+  }
+
+  /**
+   * @deprecated Use {@link DashDownloader#DashDownloader(MediaItem, Parser,
+   * CacheDataSource.Factory, Executor, long)} instead.
+   */
+  @Deprecated
+  public DashDownloader(
+      MediaItem mediaItem,
+      Parser<DashManifest> manifestParser,
+      CacheDataSource.Factory cacheDataSourceFactory,
+      Executor executor
+  ) {
+    super(
+        mediaItem,
+        manifestParser,
+        cacheDataSourceFactory,
+        executor,
+        DEFAULT_MAX_MERGED_SEGMENT_START_TIME_DIFF_US
+    );
+    baseUrlExclusionList = new BaseUrlExclusionList();
   }
 
   /**
@@ -113,13 +134,24 @@ public final class DashDownloader extends SegmentDownloader<DashManifest> {
    * @param executor An {@link Executor} used to make requests for the media being downloaded.
    *     Providing an {@link Executor} that uses multiple threads will speed up the download by
    *     allowing parts of it to be executed in parallel.
+   * @param maxMergedSegmentStartTimeDiffMs The maximum difference of the start time of two segments,
+   *     up to which the segments (of the same URI) should be merged into a single download segment,
+   *     in milliseconds.
    */
   public DashDownloader(
       MediaItem mediaItem,
       Parser<DashManifest> manifestParser,
       CacheDataSource.Factory cacheDataSourceFactory,
-      Executor executor) {
+      Executor executor,
-    super(mediaItem, manifestParser, cacheDataSourceFactory, executor);
+      long maxMergedSegmentStartTimeDiffMs
+  ) {
+    super(
+        mediaItem,
+        manifestParser,
+        cacheDataSourceFactory,
+        executor,
+        maxMergedSegmentStartTimeDiffMs
+    );
     baseUrlExclusionList = new BaseUrlExclusionList();
   }
 

libraries/exoplayer_hls/src/main/java/androidx/media3/exoplayer/hls/offline/HlsDownloader.java

@@ -89,7 +89,33 @@ public final class HlsDownloader extends SegmentDownloader<HlsPlaylist> {
    */
   public HlsDownloader(
       MediaItem mediaItem, CacheDataSource.Factory cacheDataSourceFactory, Executor executor) {
-    this(mediaItem, new HlsPlaylistParser(), cacheDataSourceFactory, executor);
+    this(
+        mediaItem,
+        new HlsPlaylistParser(),
+        cacheDataSourceFactory,
+        executor,
+        DEFAULT_MAX_MERGED_SEGMENT_START_TIME_DIFF_US
+    );
+  }
+
+  /**
+   * @deprecated Use {@link HlsDownloader#HlsDownloader(MediaItem, Parser,
+   * CacheDataSource.Factory, Executor, long)} instead.
+   */
+  @Deprecated
+  public HlsDownloader(
+      MediaItem mediaItem,
+      Parser<HlsPlaylist> manifestParser,
+      CacheDataSource.Factory cacheDataSourceFactory,
+      Executor executor
+  ) {
+    super(
+        mediaItem,
+        manifestParser,
+        cacheDataSourceFactory,
+        executor,
+        DEFAULT_MAX_MERGED_SEGMENT_START_TIME_DIFF_US
+    );
   }
 
   /**
@@ -102,13 +128,24 @@ public final class HlsDownloader extends SegmentDownloader<HlsPlaylist> {
    * @param executor An {@link Executor} used to make requests for the media being downloaded.
    *     Providing an {@link Executor} that uses multiple threads will speed up the download by
    *     allowing parts of it to be executed in parallel.
+   * @param maxMergedSegmentStartTimeDiffMs The maximum difference of the start time of two segments,
+   *     up to which the segments (of the same URI) should be merged into a single download segment,
+   *     in milliseconds.
    */
   public HlsDownloader(
       MediaItem mediaItem,
       Parser<HlsPlaylist> manifestParser,
       CacheDataSource.Factory cacheDataSourceFactory,
-      Executor executor) {
+      Executor executor,
-    super(mediaItem, manifestParser, cacheDataSourceFactory, executor);
+      long maxMergedSegmentStartTimeDiffMs
+  ) {
+    super(
+        mediaItem,
+        manifestParser,
+        cacheDataSourceFactory,
+        executor,
+        maxMergedSegmentStartTimeDiffMs
+    );
   }
 
   @Override

libraries/exoplayer_smoothstreaming/src/main/java/androidx/media3/exoplayer/smoothstreaming/offline/SsDownloader.java

@@ -93,7 +93,29 @@ public final class SsDownloader extends SegmentDownloader<SsManifest> {
             .build(),
         new SsManifestParser(),
         cacheDataSourceFactory,
-        executor);
+        executor,
+        DEFAULT_MAX_MERGED_SEGMENT_START_TIME_DIFF_US
+    );
+  }
+
+  /**
+   * @deprecated Use {@link SsDownloader#SsDownloader(MediaItem, Parser,
+   * CacheDataSource.Factory, Executor, long)} instead.
+   */
+  @Deprecated
+  public SsDownloader(
+      MediaItem mediaItem,
+      Parser<SsManifest> manifestParser,
+      CacheDataSource.Factory cacheDataSourceFactory,
+      Executor executor
+  ) {
+    super(
+        mediaItem,
+        manifestParser,
+        cacheDataSourceFactory,
+        executor,
+        DEFAULT_MAX_MERGED_SEGMENT_START_TIME_DIFF_US
+    );
   }
 
   /**
@@ -106,13 +128,24 @@ public final class SsDownloader extends SegmentDownloader<SsManifest> {
    * @param executor An {@link Executor} used to make requests for the media being downloaded.
    *     Providing an {@link Executor} that uses multiple threads will speed up the download by
    *     allowing parts of it to be executed in parallel.
+   * @param maxMergedSegmentStartTimeDiffMs The maximum difference of the start time of two segments,
+   *     up to which the segments (of the same URI) should be merged into a single download segment,
+   *     in milliseconds.
    */
   public SsDownloader(
       MediaItem mediaItem,
       Parser<SsManifest> manifestParser,
       CacheDataSource.Factory cacheDataSourceFactory,
-      Executor executor) {
+      Executor executor,
-    super(mediaItem, manifestParser, cacheDataSourceFactory, executor);
+      long maxMergedSegmentStartTimeDiffMs
+  ) {
+    super(
+        mediaItem,
+        manifestParser,
+        cacheDataSourceFactory,
+        executor,
+        maxMergedSegmentStartTimeDiffMs
+    );
   }
 
   @Override