Make sure not to create new playback sessions while still IDLE.

The first session should only be created once we have the media items
and/or called prepare. Otherwise the first session is created with
an EventTime having an empty timeline making it less useful.

issue:#7193
PiperOrigin-RevId: 308100555

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

@@ -245,7 +245,7 @@ public final class PlaybackStatsListener
   @Override
   public void onPlaybackStateChanged(EventTime eventTime, @Player.State int state) {
     playbackState = state;
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       boolean belongsToPlayback = sessionManager.belongsToSession(eventTime, session);
       playbackStatsTrackers
@@ -258,7 +258,7 @@ public final class PlaybackStatsListener
   public void onPlayWhenReadyChanged(
       EventTime eventTime, boolean playWhenReady, @Player.PlayWhenReadyChangeReason int reason) {
     this.playWhenReady = playWhenReady;
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       boolean belongsToPlayback = sessionManager.belongsToSession(eventTime, session);
       playbackStatsTrackers
@@ -271,7 +271,7 @@ public final class PlaybackStatsListener
   public void onPlaybackSuppressionReasonChanged(
       EventTime eventTime, int playbackSuppressionReason) {
     isSuppressed = playbackSuppressionReason != Player.PLAYBACK_SUPPRESSION_REASON_NONE;
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       boolean belongsToPlayback = sessionManager.belongsToSession(eventTime, session);
       playbackStatsTrackers
@@ -283,7 +283,7 @@ public final class PlaybackStatsListener
   @Override
   public void onTimelineChanged(EventTime eventTime, int reason) {
     sessionManager.handleTimelineUpdate(eventTime);
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       if (sessionManager.belongsToSession(eventTime, session)) {
         playbackStatsTrackers.get(session).onPositionDiscontinuity(eventTime);
@@ -294,7 +294,7 @@ public final class PlaybackStatsListener
   @Override
   public void onPositionDiscontinuity(EventTime eventTime, int reason) {
     sessionManager.handlePositionDiscontinuity(eventTime, reason);
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       if (sessionManager.belongsToSession(eventTime, session)) {
         playbackStatsTrackers.get(session).onPositionDiscontinuity(eventTime);
@@ -304,7 +304,7 @@ public final class PlaybackStatsListener
 
   @Override
   public void onSeekStarted(EventTime eventTime) {
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       boolean belongsToPlayback = sessionManager.belongsToSession(eventTime, session);
       playbackStatsTrackers.get(session).onSeekStarted(eventTime, belongsToPlayback);
@@ -314,7 +314,7 @@ public final class PlaybackStatsListener
 
   @Override
   public void onSeekProcessed(EventTime eventTime) {
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       boolean belongsToPlayback = sessionManager.belongsToSession(eventTime, session);
       playbackStatsTrackers.get(session).onSeekProcessed(eventTime, belongsToPlayback);
@@ -324,7 +324,7 @@ public final class PlaybackStatsListener
 
   @Override
   public void onPlayerError(EventTime eventTime, ExoPlaybackException error) {
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       if (sessionManager.belongsToSession(eventTime, session)) {
         playbackStatsTrackers.get(session).onFatalError(eventTime, error);
@@ -335,7 +335,7 @@ public final class PlaybackStatsListener
   @Override
   public void onPlaybackSpeedChanged(EventTime eventTime, float playbackSpeed) {
     this.playbackSpeed = playbackSpeed;
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (PlaybackStatsTracker tracker : playbackStatsTrackers.values()) {
       tracker.onPlaybackSpeedChanged(eventTime, playbackSpeed);
     }
@@ -344,7 +344,7 @@ public final class PlaybackStatsListener
   @Override
   public void onTracksChanged(
       EventTime eventTime, TrackGroupArray trackGroups, TrackSelectionArray trackSelections) {
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       if (sessionManager.belongsToSession(eventTime, session)) {
         playbackStatsTrackers.get(session).onTracksChanged(eventTime, trackSelections);
@@ -355,7 +355,7 @@ public final class PlaybackStatsListener
   @Override
   public void onLoadStarted(
       EventTime eventTime, LoadEventInfo loadEventInfo, MediaLoadData mediaLoadData) {
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       if (sessionManager.belongsToSession(eventTime, session)) {
         playbackStatsTrackers.get(session).onLoadStarted(eventTime);
@@ -365,7 +365,7 @@ public final class PlaybackStatsListener
 
   @Override
   public void onDownstreamFormatChanged(EventTime eventTime, MediaLoadData mediaLoadData) {
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       if (sessionManager.belongsToSession(eventTime, session)) {
         playbackStatsTrackers.get(session).onDownstreamFormatChanged(eventTime, mediaLoadData);
@@ -380,7 +380,7 @@ public final class PlaybackStatsListener
       int height,
       int unappliedRotationDegrees,
       float pixelWidthHeightRatio) {
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       if (sessionManager.belongsToSession(eventTime, session)) {
         playbackStatsTrackers.get(session).onVideoSizeChanged(eventTime, width, height);
@@ -391,7 +391,7 @@ public final class PlaybackStatsListener
   @Override
   public void onBandwidthEstimate(
       EventTime eventTime, int totalLoadTimeMs, long totalBytesLoaded, long bitrateEstimate) {
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       if (sessionManager.belongsToSession(eventTime, session)) {
         playbackStatsTrackers.get(session).onBandwidthData(totalLoadTimeMs, totalBytesLoaded);
@@ -402,7 +402,7 @@ public final class PlaybackStatsListener
   @Override
   public void onAudioUnderrun(
       EventTime eventTime, int bufferSize, long bufferSizeMs, long elapsedSinceLastFeedMs) {
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       if (sessionManager.belongsToSession(eventTime, session)) {
         playbackStatsTrackers.get(session).onAudioUnderrun();
@@ -412,7 +412,7 @@ public final class PlaybackStatsListener
 
   @Override
   public void onDroppedVideoFrames(EventTime eventTime, int droppedFrames, long elapsedMs) {
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       if (sessionManager.belongsToSession(eventTime, session)) {
         playbackStatsTrackers.get(session).onDroppedVideoFrames(droppedFrames);
@@ -427,7 +427,7 @@ public final class PlaybackStatsListener
       MediaLoadData mediaLoadData,
       IOException error,
       boolean wasCanceled) {
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       if (sessionManager.belongsToSession(eventTime, session)) {
         playbackStatsTrackers.get(session).onNonFatalError(eventTime, error);
@@ -437,7 +437,7 @@ public final class PlaybackStatsListener
 
   @Override
   public void onDrmSessionManagerError(EventTime eventTime, Exception error) {
-    sessionManager.updateSessions(eventTime);
+    maybeAddSession(eventTime);
     for (String session : playbackStatsTrackers.keySet()) {
       if (sessionManager.belongsToSession(eventTime, session)) {
         playbackStatsTrackers.get(session).onNonFatalError(eventTime, error);
@@ -445,6 +445,13 @@ public final class PlaybackStatsListener
     }
   }
 
+  private void maybeAddSession(EventTime eventTime) {
+    boolean isCompletelyIdle = eventTime.timeline.isEmpty() && playbackState == Player.STATE_IDLE;
+    if (!isCompletelyIdle) {
+      sessionManager.updateSessions(eventTime);
+    }
+  }
+
   /** Tracker for playback stats of a single playback. */
   private static final class PlaybackStatsTracker {
 

library/core/src/test/java/com/google/android/exoplayer2/analytics/PlaybackStatsListenerTest.java

@@ -21,6 +21,8 @@ import androidx.annotation.Nullable;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.Timeline;
+import com.google.android.exoplayer2.source.MediaSource;
+import com.google.android.exoplayer2.testutil.FakeTimeline;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -28,7 +30,7 @@ import org.junit.runner.RunWith;
 @RunWith(AndroidJUnit4.class)
 public final class PlaybackStatsListenerTest {
 
-  private static final AnalyticsListener.EventTime TEST_EVENT_TIME =
+  private static final AnalyticsListener.EventTime EMPTY_TIMELINE_EVENT_TIME =
       new AnalyticsListener.EventTime(
           /* realtimeMs= */ 500,
           Timeline.EMPTY,
@@ -37,6 +39,58 @@ public final class PlaybackStatsListenerTest {
           /* eventPlaybackPositionMs= */ 0,
           /* currentPlaybackPositionMs= */ 0,
           /* totalBufferedDurationMs= */ 0);
+  private static final Timeline TEST_TIMELINE = new FakeTimeline(/* windowCount= */ 1);
+  private static final AnalyticsListener.EventTime TEST_EVENT_TIME =
+      new AnalyticsListener.EventTime(
+          /* realtimeMs= */ 700,
+          TEST_TIMELINE,
+          /* windowIndex= */ 0,
+          new MediaSource.MediaPeriodId(
+              TEST_TIMELINE.getPeriod(
+                      /* periodIndex= */ 0, new Timeline.Period(), /* setIds= */ true)
+                  .uid,
+              /* windowSequenceNumber= */ 42),
+          /* eventPlaybackPositionMs= */ 123,
+          /* currentPlaybackPositionMs= */ 123,
+          /* totalBufferedDurationMs= */ 456);
+
+  @Test
+  public void events_duringInitialIdleState_dontCreateNewPlaybackStats() {
+    PlaybackStatsListener playbackStatsListener =
+        new PlaybackStatsListener(/* keepHistory= */ true, /* callback= */ null);
+
+    playbackStatsListener.onPositionDiscontinuity(
+        EMPTY_TIMELINE_EVENT_TIME, Player.DISCONTINUITY_REASON_SEEK);
+    playbackStatsListener.onPlaybackSpeedChanged(
+        EMPTY_TIMELINE_EVENT_TIME, /* playbackSpeed= */ 2.0f);
+    playbackStatsListener.onPlayWhenReadyChanged(
+        EMPTY_TIMELINE_EVENT_TIME,
+        /* playWhenReady= */ true,
+        Player.PLAY_WHEN_READY_CHANGE_REASON_USER_REQUEST);
+
+    assertThat(playbackStatsListener.getPlaybackStats()).isNull();
+  }
+
+  @Test
+  public void stateChangeEvent_toNonIdle_createsInitialPlaybackStats() {
+    PlaybackStatsListener playbackStatsListener =
+        new PlaybackStatsListener(/* keepHistory= */ true, /* callback= */ null);
+
+    playbackStatsListener.onPlaybackStateChanged(EMPTY_TIMELINE_EVENT_TIME, Player.STATE_BUFFERING);
+
+    assertThat(playbackStatsListener.getPlaybackStats()).isNotNull();
+  }
+
+  @Test
+  public void timelineChangeEvent_toNonEmpty_createsInitialPlaybackStats() {
+    PlaybackStatsListener playbackStatsListener =
+        new PlaybackStatsListener(/* keepHistory= */ true, /* callback= */ null);
+
+    playbackStatsListener.onTimelineChanged(
+        TEST_EVENT_TIME, Player.TIMELINE_CHANGE_REASON_PLAYLIST_CHANGED);
+
+    assertThat(playbackStatsListener.getPlaybackStats()).isNotNull();
+  }
 
   @Test
   public void playback_withKeepHistory_updatesStats() {