Make use of position discontinuity changes.

The extended onPositionDiscontinuity callback can be used to improve some
listener classes:
 - Listening to onTimelineChanged to detect discontinuities is no longer needed.
 - Listening to onSeekStarted is no longer needed as the start position is part
   of the onPositionDiscontinuty callback.
 - The exact old position is also useful for media time history logging.

As a side effect, removing onSeekStarted handling from PlaybackStatsListener
fixes Issue: #8675 that was caused by the special EventTime handling for
onSeekStarted.

PiperOrigin-RevId: 365558959

library/core/src/main/java/com/google/android/exoplayer2/analytics/DefaultPlaybackSessionManager.java

@@ -33,6 +33,7 @@ import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Random;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /**
  * Default {@link PlaybackSessionManager} which instantiates a new session for each window in the
@@ -184,7 +185,7 @@ public final class DefaultPlaybackSessionManager implements PlaybackSessionManag
         }
       }
     }
-    updateSessionsWithDiscontinuity(eventTime, Player.DISCONTINUITY_REASON_INTERNAL);
+    updateCurrentSession(eventTime);
   }
 
   @Override
@@ -208,6 +209,31 @@ public final class DefaultPlaybackSessionManager implements PlaybackSessionManag
         }
       }
     }
+    updateCurrentSession(eventTime);
+  }
+
+  @Override
+  @Nullable
+  public synchronized String getActiveSessionId() {
+    return currentSessionId;
+  }
+
+  @Override
+  public synchronized void finishAllSessions(EventTime eventTime) {
+    currentSessionId = null;
+    Iterator<SessionDescriptor> iterator = sessions.values().iterator();
+    while (iterator.hasNext()) {
+      SessionDescriptor session = iterator.next();
+      iterator.remove();
+      if (session.isCreated && listener != null) {
+        listener.onSessionFinished(
+            eventTime, session.sessionId, /* automaticTransitionToNextPlayback= */ false);
+      }
+    }
+  }
+
+  @RequiresNonNull("listener")
+  private void updateCurrentSession(EventTime eventTime) {
     @Nullable SessionDescriptor previousSessionDescriptor = sessions.get(currentSessionId);
     SessionDescriptor currentSessionDescriptor =
         getOrAddSession(eventTime.windowIndex, eventTime.mediaPeriodId);
@@ -234,20 +260,6 @@ public final class DefaultPlaybackSessionManager implements PlaybackSessionManag
     }
   }
 
-  @Override
-  public void finishAllSessions(EventTime eventTime) {
-    currentSessionId = null;
-    Iterator<SessionDescriptor> iterator = sessions.values().iterator();
-    while (iterator.hasNext()) {
-      SessionDescriptor session = iterator.next();
-      iterator.remove();
-      if (session.isCreated && listener != null) {
-        listener.onSessionFinished(
-            eventTime, session.sessionId, /* automaticTransitionToNextPlayback= */ false);
-      }
-    }
-  }
-
   private SessionDescriptor getOrAddSession(
       int windowIndex, @Nullable MediaPeriodId mediaPeriodId) {
     // There should only be one matching session if mediaPeriodId is non-null. If mediaPeriodId is

library/core/src/main/java/com/google/android/exoplayer2/analytics/PlaybackSessionManager.java

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.analytics;
 
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.Player.DiscontinuityReason;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.analytics.AnalyticsListener.EventTime;
@@ -128,6 +129,13 @@ public interface PlaybackSessionManager {
    */
   void updateSessionsWithDiscontinuity(EventTime eventTime, @DiscontinuityReason int reason);
 
+  /**
+   * Returns the session identifier of the session that is currently actively playing, or {@code
+   * null} if there no such session.
+   */
+  @Nullable
+  String getActiveSessionId();
+
   /**
    * Finishes all existing sessions and calls their respective {@link
    * Listener#onSessionFinished(EventTime, String, boolean)} callback.

library/core/src/main/java/com/google/android/exoplayer2/analytics/PlaybackStatsListener.java

@@ -79,19 +79,18 @@ public final class PlaybackStatsListener
   private final Period period;
 
   private PlaybackStats finishedPlaybackStats;
-  @Nullable private String activeContentPlayback;
-  @Nullable private String activeAdPlayback;
 
-  @Nullable private EventTime onSeekStartedEventTime;
+  @Nullable private String discontinuityFromSession;
-  @Player.DiscontinuityReason int discontinuityReason;
+  private long discontinuityFromPositionMs;
-  int droppedFrames;
+  @Player.DiscontinuityReason private int discontinuityReason;
-  @Nullable Exception nonFatalException;
+  private int droppedFrames;
-  long bandwidthTimeMs;
+  @Nullable private Exception nonFatalException;
-  long bandwidthBytes;
+  private long bandwidthTimeMs;
-  @Nullable Format videoFormat;
+  private long bandwidthBytes;
-  @Nullable Format audioFormat;
+  @Nullable private Format videoFormat;
-  int videoHeight;
+  @Nullable private Format audioFormat;
-  int videoWidth;
+  private int videoHeight;
+  private int videoWidth;
 
   /**
    * Creates listener for playback stats.
@@ -137,13 +136,10 @@ public final class PlaybackStatsListener
    */
   @Nullable
   public PlaybackStats getPlaybackStats() {
+    @Nullable String activeSessionId = sessionManager.getActiveSessionId();
     @Nullable
     PlaybackStatsTracker activeStatsTracker =
-        activeAdPlayback != null
+        activeSessionId == null ? null : playbackStatsTrackers.get(activeSessionId);
-            ? playbackStatsTrackers.get(activeAdPlayback)
-            : activeContentPlayback != null
-                ? playbackStatsTrackers.get(activeContentPlayback)
-                : null;
     return activeStatsTracker == null ? null : activeStatsTracker.build(/* isFinal= */ false);
   }
 
@@ -159,11 +155,6 @@ public final class PlaybackStatsListener
   @Override
   public void onSessionActive(EventTime eventTime, String session) {
     checkNotNull(playbackStatsTrackers.get(session)).onForeground();
-    if (eventTime.mediaPeriodId != null && eventTime.mediaPeriodId.isAd()) {
-      activeAdPlayback = session;
-    } else {
-      activeContentPlayback = session;
-    }
   }
 
   @Override
@@ -173,14 +164,11 @@ public final class PlaybackStatsListener
 
   @Override
   public void onSessionFinished(EventTime eventTime, String session, boolean automaticTransition) {
-    if (session.equals(activeAdPlayback)) {
-      activeAdPlayback = null;
-    } else if (session.equals(activeContentPlayback)) {
-      activeContentPlayback = null;
-    }
     PlaybackStatsTracker tracker = checkNotNull(playbackStatsTrackers.remove(session));
     EventTime startEventTime = checkNotNull(sessionStartEventTimes.remove(session));
-    tracker.onFinished(eventTime, automaticTransition);
+    long discontinuityFromPositionMs =
+        session.equals(discontinuityFromSession) ? this.discontinuityFromPositionMs : C.TIME_UNSET;
+    tracker.onFinished(eventTime, automaticTransition, discontinuityFromPositionMs);
     PlaybackStats playbackStats = tracker.build(/* isFinal= */ true);
     finishedPlaybackStats = PlaybackStats.merge(finishedPlaybackStats, playbackStats);
     if (callback != null) {
@@ -191,13 +179,16 @@ public final class PlaybackStatsListener
   // AnalyticsListener implementation.
 
   @Override
-  public void onPositionDiscontinuity(EventTime eventTime, @Player.DiscontinuityReason int reason) {
+  public void onPositionDiscontinuity(
-    discontinuityReason = reason;
+      EventTime eventTime,
+      Player.PositionInfo oldPositionInfo,
+      Player.PositionInfo newPositionInfo,
+      @Player.DiscontinuityReason int reason) {
+    if (discontinuityFromSession == null) {
+      discontinuityFromSession = sessionManager.getActiveSessionId();
+      discontinuityFromPositionMs = oldPositionInfo.positionMs;
     }
-
+    discontinuityReason = reason;
-  @Override
-  public void onSeekStarted(EventTime eventTime) {
-    onSeekStartedEventTime = eventTime;
   }
 
   @Override
@@ -253,9 +244,7 @@ public final class PlaybackStatsListener
     for (String session : playbackStatsTrackers.keySet()) {
       Pair<EventTime, Boolean> eventTimeAndBelongsToPlayback = findBestEventTime(events, session);
       PlaybackStatsTracker tracker = playbackStatsTrackers.get(session);
-      boolean hasPositionDiscontinuity =
+      boolean hasDiscontinuityToPlayback = hasEvent(events, session, EVENT_POSITION_DISCONTINUITY);
-          hasEvent(events, session, EVENT_POSITION_DISCONTINUITY)
-              || hasEvent(events, session, EVENT_TIMELINE_CHANGED);
       boolean hasDroppedFrames = hasEvent(events, session, EVENT_DROPPED_VIDEO_FRAMES);
       boolean hasAudioUnderrun = hasEvent(events, session, EVENT_AUDIO_UNDERRUN);
       boolean startedLoading = hasEvent(events, session, EVENT_LOAD_STARTED);
@@ -270,8 +259,8 @@ public final class PlaybackStatsListener
           player,
           /* eventTime= */ eventTimeAndBelongsToPlayback.first,
           /* belongsToPlayback= */ eventTimeAndBelongsToPlayback.second,
-          /* seeked= */ onSeekStartedEventTime != null,
+          session.equals(discontinuityFromSession) ? discontinuityFromPositionMs : C.TIME_UNSET,
-          hasPositionDiscontinuity,
+          hasDiscontinuityToPlayback,
           hasDroppedFrames ? droppedFrames : 0,
           hasAudioUnderrun,
           startedLoading,
@@ -284,9 +273,9 @@ public final class PlaybackStatsListener
           hasVideoSize ? videoHeight : Format.NO_VALUE,
           hasVideoSize ? videoWidth : Format.NO_VALUE);
     }
-    onSeekStartedEventTime = null;
     videoFormat = null;
     audioFormat = null;
+    discontinuityFromSession = null;
     if (events.contains(AnalyticsListener.EVENT_PLAYER_RELEASED)) {
       sessionManager.finishAllSessions(events.getEventTime(EVENT_PLAYER_RELEASED));
     }
@@ -311,11 +300,8 @@ public final class PlaybackStatsListener
   }
 
   private Pair<EventTime, Boolean> findBestEventTime(Events events, String session) {
-    // Check all event times of the events as well as the event time when a seek started.
+    @Nullable EventTime eventTime = null;
-    @Nullable EventTime eventTime = onSeekStartedEventTime;
+    boolean belongsToPlayback = false;
-    boolean belongsToPlayback =
-        onSeekStartedEventTime != null
-            && sessionManager.belongsToSession(onSeekStartedEventTime, session);
     for (int i = 0; i < events.size(); i++) {
       @EventFlags int event = events.get(i);
       EventTime newEventTime = events.getEventTime(event);
@@ -463,15 +449,18 @@ public final class PlaybackStatsListener
      * @param eventTime The {@link EventTime}. Does not belong to this playback.
      * @param automaticTransition Whether the playback finished because of an automatic transition
      *     to the next playback item.
+     * @param discontinuityFromPositionMs The position before the discontinuity from this playback,
+     *     {@link C#TIME_UNSET} if no discontinuity started from this playback.
      */
-    public void onFinished(EventTime eventTime, boolean automaticTransition) {
+    public void onFinished(
+        EventTime eventTime, boolean automaticTransition, long discontinuityFromPositionMs) {
       // Simulate state change to ENDED to record natural ending of playback.
       @PlaybackState
       int finalPlaybackState =
           currentPlaybackState == PlaybackStats.PLAYBACK_STATE_ENDED || automaticTransition
               ? PlaybackStats.PLAYBACK_STATE_ENDED
               : PlaybackStats.PLAYBACK_STATE_ABANDONED;
-      maybeUpdateMediaTimeHistory(eventTime.realtimeMs, /* mediaTimeMs= */ C.TIME_UNSET);
+      maybeUpdateMediaTimeHistory(eventTime.realtimeMs, discontinuityFromPositionMs);
       maybeRecordVideoFormatTime(eventTime.realtimeMs);
       maybeRecordAudioFormatTime(eventTime.realtimeMs);
       updatePlaybackState(finalPlaybackState, eventTime);
@@ -483,8 +472,9 @@ public final class PlaybackStatsListener
      * @param player The {@link Player}.
      * @param eventTime The {@link EventTime} of the events.
      * @param belongsToPlayback Whether the {@code eventTime} belongs to this playback.
-     * @param seeked Whether a seek occurred.
+     * @param discontinuityFromPositionMs The position before the discontinuity from this playback,
-     * @param positionDiscontinuity Whether a position discontinuity occurred for this playback.
+     *     or {@link C#TIME_UNSET} if no discontinuity started from this playback.
+     * @param hasDiscontinuity Whether a discontinuity to this playback occurred.
      * @param droppedFrameCount The number of newly dropped frames for this playback.
      * @param hasAudioUnderun Whether a new audio underrun occurred for this playback.
      * @param startedLoading Whether this playback started loading.
@@ -501,8 +491,8 @@ public final class PlaybackStatsListener
         Player player,
         EventTime eventTime,
         boolean belongsToPlayback,
-        boolean seeked,
+        long discontinuityFromPositionMs,
-        boolean positionDiscontinuity,
+        boolean hasDiscontinuity,
         int droppedFrameCount,
         boolean hasAudioUnderun,
         boolean startedLoading,
@@ -514,7 +504,8 @@ public final class PlaybackStatsListener
         @Nullable Format audioFormat,
         int videoHeight,
         int videoWidth) {
-      if (seeked) {
+      if (discontinuityFromPositionMs != C.TIME_UNSET) {
+        maybeUpdateMediaTimeHistory(eventTime.realtimeMs, discontinuityFromPositionMs);
         isSeeking = true;
       }
       if (player.getPlaybackState() != Player.STATE_BUFFERING) {
@@ -523,7 +514,7 @@ public final class PlaybackStatsListener
       int playerPlaybackState = player.getPlaybackState();
       if (playerPlaybackState == Player.STATE_IDLE
           || playerPlaybackState == Player.STATE_ENDED
-          || positionDiscontinuity) {
+          || hasDiscontinuity) {
         isInterruptedByAd = false;
       }
       if (fatalError != null) {

library/core/src/main/java/com/google/android/exoplayer2/util/EventLogger.java

@@ -187,11 +187,6 @@ public class EventLogger implements AnalyticsListener {
     logd(eventTime, "positionDiscontinuity", builder.toString());
   }
 
-  @Override
-  public void onSeekStarted(EventTime eventTime) {
-    logd(eventTime, "seekStarted");
-  }
-
   @Override
   public void onPlaybackParametersChanged(
       EventTime eventTime, PlaybackParameters playbackParameters) {