Add flag to SinglePeriodTimeline to suppress projection

Issue: #9037
#minor-release
PiperOrigin-RevId: 385630065

RELEASENOTES.md

@@ -39,6 +39,9 @@
         ([#9004](https://github.com/google/ExoPlayer/issues/9004)).
     *   Forward the FRAME-RATE value from the master playlist to renditions.
         ([#8960](https://github.com/google/ExoPlayer/issues/8960)).
+    *   Fix issue where HLS events would start at positions greater than
+        specified by an `EXT-X-START` tag when placed in a playlist
+        ([#9037](https://github.com/google/ExoPlayer/issues/9037)).
 *   Ad playback:
     *   Use the content URI when auto-generating an ad ID (in addition to the
         media ID and ad tag URI)

library/core/src/main/java/com/google/android/exoplayer2/source/SinglePeriodTimeline.java

@@ -40,6 +40,7 @@ public final class SinglePeriodTimeline extends Timeline {
   private final long windowDefaultStartPositionUs;
   private final boolean isSeekable;
   private final boolean isDynamic;
+  private final boolean suppressPositionProjection;
   @Nullable private final Object manifest;
   @Nullable private final MediaItem mediaItem;
   @Nullable private final MediaItem.LiveConfiguration liveConfiguration;
@@ -169,6 +170,7 @@ public final class SinglePeriodTimeline extends Timeline {
         windowDefaultStartPositionUs,
         isSeekable,
         isDynamic,
+        /* suppressPositionProjection= */ false,
         manifest,
         mediaItem,
         useLiveConfiguration ? mediaItem.liveConfiguration : null);
@@ -176,7 +178,7 @@ public final class SinglePeriodTimeline extends Timeline {
 
   /**
    * @deprecated Use {@link #SinglePeriodTimeline(long, long, long, long, long, long, long, boolean,
-   *     boolean, Object, MediaItem, MediaItem.LiveConfiguration)} instead.
+   *     boolean, boolean, Object, MediaItem, MediaItem.LiveConfiguration)} instead.
    */
   @Deprecated
   public SinglePeriodTimeline(
@@ -202,11 +204,46 @@ public final class SinglePeriodTimeline extends Timeline {
         windowDefaultStartPositionUs,
         isSeekable,
         isDynamic,
+        /* suppressPositionProjection= */ false,
         manifest,
         MEDIA_ITEM.buildUpon().setTag(tag).build(),
         isLive ? MEDIA_ITEM.liveConfiguration : null);
   }
 
+  /**
+   * @deprecated Use {@link #SinglePeriodTimeline(long, long, long, long, long, long, long, boolean,
+   *     boolean, boolean, Object, MediaItem, MediaItem.LiveConfiguration)} instead.
+   */
+  @Deprecated
+  public SinglePeriodTimeline(
+      long presentationStartTimeMs,
+      long windowStartTimeMs,
+      long elapsedRealtimeEpochOffsetMs,
+      long periodDurationUs,
+      long windowDurationUs,
+      long windowPositionInPeriodUs,
+      long windowDefaultStartPositionUs,
+      boolean isSeekable,
+      boolean isDynamic,
+      @Nullable Object manifest,
+      MediaItem mediaItem,
+      @Nullable MediaItem.LiveConfiguration liveConfiguration) {
+    this(
+        presentationStartTimeMs,
+        windowStartTimeMs,
+        elapsedRealtimeEpochOffsetMs,
+        periodDurationUs,
+        windowDurationUs,
+        windowPositionInPeriodUs,
+        windowDefaultStartPositionUs,
+        isSeekable,
+        isDynamic,
+        /* suppressPositionProjection= */ false,
+        manifest,
+        mediaItem,
+        liveConfiguration);
+  }
+
   /**
    * Creates a timeline with one period, and a window of known duration starting at a specified
    * position in the period.
@@ -226,6 +263,9 @@ public final class SinglePeriodTimeline extends Timeline {
    *     which to begin playback, in microseconds.
    * @param isSeekable Whether seeking is supported within the window.
    * @param isDynamic Whether the window may change when the timeline is updated.
+   * @param suppressPositionProjection Whether {@link #getWindow(int, Window, long) position
+   *     projection} in a playlist should be suppressed. This only applies for dynamic timelines and
+   *     is ignored otherwise.
    * @param manifest The manifest. May be {@code null}.
    * @param mediaItem A media item used for {@link Timeline.Window#mediaItem}.
    * @param liveConfiguration The configuration for live playback behaviour, or {@code null} if the
@@ -241,6 +281,7 @@ public final class SinglePeriodTimeline extends Timeline {
       long windowDefaultStartPositionUs,
       boolean isSeekable,
       boolean isDynamic,
+      boolean suppressPositionProjection,
       @Nullable Object manifest,
       MediaItem mediaItem,
       @Nullable MediaItem.LiveConfiguration liveConfiguration) {
@@ -253,6 +294,7 @@ public final class SinglePeriodTimeline extends Timeline {
     this.windowDefaultStartPositionUs = windowDefaultStartPositionUs;
     this.isSeekable = isSeekable;
     this.isDynamic = isDynamic;
+    this.suppressPositionProjection = suppressPositionProjection;
     this.manifest = manifest;
     this.mediaItem = checkNotNull(mediaItem);
     this.liveConfiguration = liveConfiguration;
@@ -268,7 +310,7 @@ public final class SinglePeriodTimeline extends Timeline {
   public Window getWindow(int windowIndex, Window window, long defaultPositionProjectionUs) {
     Assertions.checkIndex(windowIndex, 0, 1);
     long windowDefaultStartPositionUs = this.windowDefaultStartPositionUs;
-    if (isDynamic && defaultPositionProjectionUs != 0) {
+    if (isDynamic && !suppressPositionProjection && defaultPositionProjectionUs != 0) {
       if (windowDurationUs == C.TIME_UNSET) {
         // Don't allow projection into a window that has an unknown duration.
         windowDefaultStartPositionUs = C.TIME_UNSET;

library/core/src/test/java/com/google/android/exoplayer2/ExoPlayerTest.java

@@ -9206,6 +9206,7 @@ public final class ExoPlayerTest {
             /* windowDefaultStartPositionUs= */ 0,
             /* isSeekable= */ true,
             /* isDynamic= */ true,
+            /* suppressPositionProjection= */ false,
             /* manifest= */ null,
             mediaItem,
             mediaItem.liveConfiguration);

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaSource.java

@@ -559,6 +559,9 @@ public final class HlsMediaSource extends BaseMediaSource
     maybeUpdateLiveConfiguration(targetLiveOffsetUs);
     long windowDefaultStartPositionUs =
         getLiveWindowDefaultStartPositionUs(playlist, liveEdgeOffsetUs);
+    boolean suppressPositionProjection =
+        playlist.playlistType == HlsMediaPlaylist.PLAYLIST_TYPE_EVENT
+            && playlist.hasPositiveStartOffset;
     return new SinglePeriodTimeline(
         presentationStartTimeMs,
         windowStartTimeMs,
@@ -569,6 +572,7 @@ public final class HlsMediaSource extends BaseMediaSource
         windowDefaultStartPositionUs,
         /* isSeekable= */ true,
         /* isDynamic= */ !playlist.hasEndTag,
+        suppressPositionProjection,
         manifest,
         mediaItem,
         liveConfiguration);
@@ -601,6 +605,7 @@ public final class HlsMediaSource extends BaseMediaSource
         windowDefaultStartPositionUs,
         /* isSeekable= */ true,
         /* isDynamic= */ false,
+        /* suppressPositionProjection= */ true,
         manifest,
         mediaItem,
         /* liveConfiguration= */ null);

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylist.java

@@ -401,6 +401,11 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
    * {@link #durationUs}, inclusive.
    */
   public final long startOffsetUs;
+  /**
+   * Whether the {@link #startOffsetUs} was explicitly defined by #EXT-X-START as a positive value
+   * or zero.
+   */
+  public final boolean hasPositiveStartOffset;
   /** Whether the start position should be precise, as defined by #EXT-X-START. */
   public final boolean preciseStart;
   /**
@@ -537,6 +542,7 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
             : startOffsetUs >= 0
                 ? min(durationUs, startOffsetUs)
                 : max(0, durationUs + startOffsetUs);
+    this.hasPositiveStartOffset = startOffsetUs >= 0;
     this.serverControl = serverControl;
   }