Avoid position jumping back when controller replaces the current item

When the controller replaces the current item, the masking position will be changed to the default position of the new item for a short while, before the correct position comes from the session. This will interrupt the current position fetched from the controller when the playback doesn't interrupted by the item replacing.

Issue: #951

#minor-release

PiperOrigin-RevId: 611417539

Author: tianyif

RELEASENOTES.md

@@ -49,6 +49,9 @@
 *   Muxers:
 *   IMA extension:
 *   Session:
+    *   Fix issue where the current position jumps back when the controller
+        replaces the current item
+        ([#951](https://github.com/androidx/media/issues/951)).
 *   UI:
     *   Fallback to include audio track language name if `Locale` cannot
         identify a display name

libraries/session/src/main/java/androidx/media3/session/MediaControllerImplBase.java

@@ -970,7 +970,9 @@ private void addMediaItemsInternal(int index, List<MediaItem> mediaItems) {
     }
     // Add media items to the end of the timeline if the index exceeds the window count.
     index = min(index, playerInfo.timeline.getWindowCount());
-    PlayerInfo newPlayerInfo = maskPlaybackInfoForAddedItems(playerInfo, index, mediaItems);
+    PlayerInfo newPlayerInfo =
+        maskPlayerInfoForAddedItems(
+            playerInfo, index, mediaItems, getCurrentPosition(), getContentPosition());
     @Nullable
     @Player.MediaItemTransitionReason
     Integer mediaItemTransitionReason =
@@ -983,8 +985,23 @@ private void addMediaItemsInternal(int index, List<MediaItem> mediaItems) {
         /* mediaItemTransitionReason= */ mediaItemTransitionReason);
   }
 
-  private static PlayerInfo maskPlaybackInfoForAddedItems(
-      PlayerInfo playerInfo, int index, List<MediaItem> mediaItems) {
+  /**
+   * Returns a masking {@link PlayerInfo} for the added {@linkplain MediaItem media items} with the
+   * provided information.
+   *
+   * @param playerInfo The {@link PlayerInfo} that the new masking {@link PlayerInfo} is based on.
+   * @param index The index at which the {@linkplain MediaItem media items} are added.
+   * @param mediaItems The {@linkplain MediaItem media items} added.
+   * @param currentPositionMs The current position in milliseconds.
+   * @param currentContentPositionMs The current content position in milliseconds.
+   * @return A masking {@link PlayerInfo}.
+   */
+  private static PlayerInfo maskPlayerInfoForAddedItems(
+      PlayerInfo playerInfo,
+      int index,
+      List<MediaItem> mediaItems,
+      long currentPositionMs,
+      long currentContentPositionMs) {
     Timeline oldTimeline = playerInfo.timeline;
     List<Window> newWindows = new ArrayList<>();
     List<Period> newPeriods = new ArrayList<>();
@@ -1017,6 +1034,8 @@ private static PlayerInfo maskPlaybackInfoForAddedItems(
         newTimeline,
         newMediaItemIndex,
         newPeriodIndex,
+        currentPositionMs,
+        currentContentPositionMs,
         Player.DISCONTINUITY_REASON_INTERNAL);
   }
 
@@ -1066,7 +1085,14 @@ private void removeMediaItemsInternal(int fromIndex, int toIndex) {
     }
     boolean wasCurrentItemRemoved =
         getCurrentMediaItemIndex() >= fromIndex && getCurrentMediaItemIndex() < toIndex;
-    PlayerInfo newPlayerInfo = maskPlayerInfoForRemovedItems(playerInfo, fromIndex, toIndex);
+    PlayerInfo newPlayerInfo =
+        maskPlayerInfoForRemovedItems(
+            playerInfo,
+            fromIndex,
+            toIndex,
+            /* isReplacingItems= */ false,
+            getCurrentPosition(),
+            getContentPosition());
     boolean didMediaItemTransitionHappen =
         playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex >= fromIndex
             && playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex < toIndex;
@@ -1082,8 +1108,30 @@ private void removeMediaItemsInternal(int fromIndex, int toIndex) {
             : null);
   }
 
+  /**
+   * Returns a masking {@link PlayerInfo} for the removed {@linkplain MediaItem media items} with
+   * the provided information.
+   *
+   * @param playerInfo The {@link PlayerInfo} that the new masking {@link PlayerInfo} is based on.
+   * @param fromIndex The index at which to start removing media items (inclusive).
+   * @param toIndex The index of the first item to be kept (exclusive).
+   * @param isReplacingItems A boolean indicating whether the media items are removed due to
+   *     replacing.
+   * @param currentPositionMs The current position in milliseconds. This value will be used in the
+   *     new masking {@link PlayerInfo} if the removal of the media items doesn't affect the current
+   *     playback position.
+   * @param currentContentPositionMs The current content position in milliseconds. This value will
+   *     be used in the new masking {@link PlayerInfo} if the removal of the media items doesn't
+   *     affect the current playback position.
+   * @return A masking {@link PlayerInfo}.
+   */
   private static PlayerInfo maskPlayerInfoForRemovedItems(
-      PlayerInfo playerInfo, int fromIndex, int toIndex) {
+      PlayerInfo playerInfo,
+      int fromIndex,
+      int toIndex,
+      boolean isReplacingItems,
+      long currentPositionMs,
+      long currentContentPositionMs) {
     Timeline oldTimeline = playerInfo.timeline;
     List<Window> newWindows = new ArrayList<>();
     List<Period> newPeriods = new ArrayList<>();
@@ -1141,6 +1189,16 @@ private static PlayerInfo maskPlayerInfoForRemovedItems(
                 newPositionInfo,
                 SessionPositionInfo.DEFAULT,
                 Player.DISCONTINUITY_REASON_REMOVE);
+      } else if (isReplacingItems) {
+        newPlayerInfo =
+            maskTimelineAndPositionInfo(
+                playerInfo,
+                newTimeline,
+                newMediaItemIndex,
+                newPeriodIndex,
+                currentPositionMs,
+                currentContentPositionMs,
+                Player.DISCONTINUITY_REASON_REMOVE);
       } else {
         Window newWindow = newTimeline.getWindow(newMediaItemIndex, new Window());
         long defaultPositionMs = newWindow.getDefaultPositionMs();
@@ -1182,6 +1240,8 @@ private static PlayerInfo maskPlayerInfoForRemovedItems(
               newTimeline,
               newMediaItemIndex,
               newPeriodIndex,
+              currentPositionMs,
+              currentContentPositionMs,
               Player.DISCONTINUITY_REASON_REMOVE);
     }
 
@@ -1290,8 +1350,17 @@ private void replaceMediaItemsInternal(int fromIndex, int toIndex, List<MediaIte
       return;
     }
     toIndex = min(toIndex, playlistSize);
-    PlayerInfo newPlayerInfo = maskPlaybackInfoForAddedItems(playerInfo, toIndex, mediaItems);
-    newPlayerInfo = maskPlayerInfoForRemovedItems(newPlayerInfo, fromIndex, toIndex);
+    PlayerInfo newPlayerInfo =
+        maskPlayerInfoForAddedItems(
+            playerInfo, toIndex, mediaItems, getCurrentPosition(), getContentPosition());
+    newPlayerInfo =
+        maskPlayerInfoForRemovedItems(
+            newPlayerInfo,
+            fromIndex,
+            toIndex,
+            /* isReplacingItems= */ true,
+            getCurrentPosition(),
+            getContentPosition());
     boolean wasCurrentItemReplaced =
         playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex >= fromIndex
             && playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex < toIndex;
@@ -2111,6 +2180,8 @@ private void moveMediaItemsInternal(int fromIndex, int toIndex, int newIndex) {
               newTimeline,
               newWindowIndex,
               newPeriodIndex,
+              getCurrentPosition(),
+              getContentPosition(),
               Player.DISCONTINUITY_REASON_INTERNAL);
 
       updatePlayerInfo(
@@ -2972,6 +3043,8 @@ private static PlayerInfo maskTimelineAndPositionInfo(
       Timeline timeline,
       int newMediaItemIndex,
       int newPeriodIndex,
+      long newPositionMs,
+      long newContentPositionMs,
       int discontinuityReason) {
     PositionInfo newPositionInfo =
         new PositionInfo(
@@ -2980,8 +3053,8 @@ private static PlayerInfo maskTimelineAndPositionInfo(
             timeline.getWindow(newMediaItemIndex, new Window()).mediaItem,
             /* periodUid= */ null,
             newPeriodIndex,
-            playerInfo.sessionPositionInfo.positionInfo.positionMs,
-            playerInfo.sessionPositionInfo.positionInfo.contentPositionMs,
+            newPositionMs,
+            newContentPositionMs,
             playerInfo.sessionPositionInfo.positionInfo.adGroupIndex,
             playerInfo.sessionPositionInfo.positionInfo.adIndexInAdGroup);
     return maskTimelineAndPositionInfo(

libraries/session/src/main/java/androidx/media3/session/MediaUtils.java

@@ -244,7 +244,8 @@ public static long getUpdatedCurrentPositionMs(
       long lastSetPlayWhenReadyCalledTimeMs,
       long timeDiffMs) {
     boolean receivedUpdatedPositionInfo =
-        lastSetPlayWhenReadyCalledTimeMs < playerInfo.sessionPositionInfo.eventTimeMs;
+        playerInfo.sessionPositionInfo.equals(SessionPositionInfo.DEFAULT)
+            || (lastSetPlayWhenReadyCalledTimeMs < playerInfo.sessionPositionInfo.eventTimeMs);
     if (!playerInfo.isPlaying) {
       if (receivedUpdatedPositionInfo || currentPositionMs == C.TIME_UNSET) {
         return playerInfo.sessionPositionInfo.positionInfo.positionMs;

libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaControllerStateMaskingTest.java

@@ -2348,6 +2348,7 @@ public void removeMediaItems_currentItemRemoved() throws Exception {
                     createMediaItems(firstMediaId, secondMediaId, thirdMediaId)))
             .setCurrentMediaItemIndex(initialMediaItemIndex)
             .setCurrentPeriodIndex(initialMediaItemIndex)
+            .setCurrentPosition(2000L)
             .build();
     remoteSession.setPlayer(playerConfig);
 
@@ -2409,6 +2410,7 @@ public void onEvents(Player player, Player.Events events) {
         /* testLastPeriodIndex= */ testCurrentMediaItemIndex);
     assertThat(newMediaItemRef.get().mediaId).isEqualTo(testCurrentMediaId);
     assertThat(newPositionInfoRef.get().mediaItemIndex).isEqualTo(testCurrentMediaItemIndex);
+    assertThat(newPositionInfoRef.get().positionMs).isEqualTo(0L);
     assertThat(getEventsAsList(onEventsRef.get()))
         .containsExactly(
             Player.EVENT_TIMELINE_CHANGED,
@@ -3439,12 +3441,14 @@ public void replaceMediaItems_replacingCurrentItem_correctMasking() throws Excep
         new RemoteMediaSession.MockPlayerConfigBuilder()
             .setTimeline(MediaTestUtils.createTimeline(3))
             .setCurrentMediaItemIndex(1)
+            .setCurrentPosition(2000L)
             .build();
     remoteSession.setPlayer(playerConfig);
     MediaController controller = controllerTestRule.createController(remoteSession.getToken());
     CountDownLatch latch = new CountDownLatch(2);
     AtomicReference<Timeline> newTimelineRef = new AtomicReference<>();
     AtomicReference<Player.Events> onEventsRef = new AtomicReference<>();
+    AtomicReference<PositionInfo> newPositionInfoRef = new AtomicReference<>();
     Player.Listener listener =
         new Player.Listener() {
           @Override
@@ -3458,6 +3462,14 @@ public void onEvents(Player player, Player.Events events) {
             onEventsRef.set(events);
             latch.countDown();
           }
+
+          @Override
+          public void onPositionDiscontinuity(
+              PositionInfo oldPosition,
+              PositionInfo newPosition,
+              @Player.DiscontinuityReason int reason) {
+            newPositionInfoRef.set(newPosition);
+          }
         };
     threadTestRule.getHandler().postAndSync(() -> controller.addListener(listener));
     AtomicInteger currentMediaItemIndexRef = new AtomicInteger();
@@ -3478,6 +3490,7 @@ public void onEvents(Player player, Player.Events events) {
             Player.EVENT_TIMELINE_CHANGED,
             Player.EVENT_POSITION_DISCONTINUITY,
             Player.EVENT_MEDIA_ITEM_TRANSITION);
+    assertThat(newPositionInfoRef.get().positionMs).isEqualTo(2000L);
   }
 
   @Test