diff --git a/extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoader.java b/extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoader.java
index 8c4fb4c51c..11aab906e0 100644
--- a/extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoader.java
+++ b/extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoader.java
@@ -430,7 +430,9 @@ public final class ImaAdsLoader implements Player.EventListener, VideoAdPlayer,
     } else if (!playingAd) {
       return VideoProgressUpdate.VIDEO_TIME_NOT_READY;
     } else {
-      return new VideoProgressUpdate(player.getCurrentPosition(), player.getDuration());
+      long adDuration = player.getDuration();
+      return adDuration == C.TIME_UNSET ? VideoProgressUpdate.VIDEO_TIME_NOT_READY
+          : new VideoProgressUpdate(player.getCurrentPosition(), adDuration);
     }
   }
 
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImpl.java b/library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImpl.java
index f22c08f585..b53cce1f74 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImpl.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImpl.java
@@ -319,8 +319,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
     if (timeline.isEmpty() || pendingSeekAcks > 0) {
       return maskingWindowPositionMs;
     } else {
-      timeline.getPeriod(playbackInfo.periodId.periodIndex, period);
-      return period.getPositionInWindowMs() + C.usToMs(playbackInfo.positionUs);
+      return playbackInfoPositionUsToWindowPositionMs(playbackInfo.positionUs);
     }
   }
 
@@ -330,8 +329,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
     if (timeline.isEmpty() || pendingSeekAcks > 0) {
       return maskingWindowPositionMs;
     } else {
-      timeline.getPeriod(playbackInfo.periodId.periodIndex, period);
-      return period.getPositionInWindowMs() + C.usToMs(playbackInfo.bufferedPositionUs);
+      return playbackInfoPositionUsToWindowPositionMs(playbackInfo.bufferedPositionUs);
     }
   }
 
@@ -358,7 +356,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
 
   @Override
   public boolean isPlayingAd() {
-    return pendingSeekAcks == 0 && playbackInfo.periodId.adGroupIndex != C.INDEX_UNSET;
+    return pendingSeekAcks == 0 && playbackInfo.periodId.isAd();
   }
 
   @Override
@@ -512,4 +510,13 @@ import java.util.concurrent.CopyOnWriteArraySet;
     }
   }
 
+  private long playbackInfoPositionUsToWindowPositionMs(long positionUs) {
+    long positionMs = C.usToMs(positionUs);
+    if (!playbackInfo.periodId.isAd()) {
+      timeline.getPeriod(playbackInfo.periodId.periodIndex, period);
+      positionMs += period.getPositionInWindowMs();
+    }
+    return positionMs;
+  }
+
 }