--- a/dom/media/mediasource/MediaSourceReader.cpp
+++ b/dom/media/mediasource/MediaSourceReader.cpp
@@ -780,16 +780,18 @@ void
 MediaSourceReader::NotifyTimeRangesChanged()
 {
   ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
   if (mWaitingForSeekData) {
     //post a task to the decode queue to try to complete the pending seek.
     RefPtr<nsIRunnable> task(NS_NewRunnableMethod(
         this, &MediaSourceReader::AttemptSeek));
     GetTaskQueue()->Dispatch(task.forget());
+  } else {
+    MaybeNotifyHaveData();
   }
 }
 
 nsRefPtr<MediaDecoderReader::SeekPromise>
 MediaSourceReader::Seek(int64_t aTime, int64_t aIgnored /* Used only for ogg which is non-MSE */)
 {
   MSE_DEBUG("Seek(aTime=%lld, aEnd=%lld, aCurrent=%lld)",
             aTime);
@@ -1016,26 +1018,34 @@ MediaSourceReader::WaitForData(MediaData
   return p;
 }
 
 void
 MediaSourceReader::MaybeNotifyHaveData()
 {
   ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
   bool haveAudio = false, haveVideo = false;
-  if (!IsSeeking() && mAudioTrack && HaveData(mLastAudioTime, MediaData::AUDIO_DATA)) {
-    haveAudio = true;
-    WaitPromise(MediaData::AUDIO_DATA).ResolveIfExists(MediaData::AUDIO_DATA, __func__);
+  bool ended = IsEnded();
+  // If we are in ended mode, we will resolve any pending wait promises.
+  // The next Request*Data will handle END_OF_STREAM or going back into waiting
+  // mode.
+  if (!IsSeeking() && mAudioTrack) {
+    haveAudio = HaveData(mLastAudioTime, MediaData::AUDIO_DATA);
+    if (ended || haveAudio) {
+      WaitPromise(MediaData::AUDIO_DATA).ResolveIfExists(MediaData::AUDIO_DATA __func__);
+    }
   }
-  if (!IsSeeking() && mVideoTrack && HaveData(mLastVideoTime, MediaData::VIDEO_DATA)) {
-    haveVideo = true;
-    WaitPromise(MediaData::VIDEO_DATA).ResolveIfExists(MediaData::VIDEO_DATA, __func__);
+  if (!IsSeeking() && mVideoTrack) {
+    haveVideo = HaveData(mLastVideoTime, MediaData::VIDEO_DATA);
+    if (ended || haveVideo) {
+      WaitPromise(MediaData::VIDEO_DATA).ResolveIfExists(MediaData::VIDEO_DATA __func__);
+    }
   }
-  MSE_DEBUG("isSeeking=%d haveAudio=%d, haveVideo=%d",
-            IsSeeking(), haveAudio, haveVideo);
+  MSE_DEBUG("isSeeking=%d haveAudio=%d, haveVideo=%d ended=%d",
+            IsSeeking(), haveAudio, haveVideo, ended);
 }
 
 static void
 CombineEncryptionData(EncryptionInfo& aTo, const EncryptionInfo& aFrom)
 {
   if (!aFrom.mIsEncrypted) {
     return;
   }
@@ -1120,16 +1130,23 @@ MediaSourceReader::ReadUpdatedMetadata(M
   *aInfo = mInfo;
 }
 
 void
 MediaSourceReader::Ended(bool aEnded)
 {
   mDecoder->GetReentrantMonitor().AssertCurrentThreadIn();
   mEnded = aEnded;
+  if (aEnded) {
+    // post a task to the decode queue to try to complete any pending
+    // seek or wait
+    RefPtr<nsIRunnable> task(NS_NewRunnableMethod(
+        this, &MediaSourceReader::NotifyTimeRangesChanged));
+    GetTaskQueue()->Dispatch(task.forget());
+  }
 }
 
 bool
 MediaSourceReader::IsEnded()
 {
   ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
   return mEnded;
 }