--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -1027,16 +1027,25 @@ public:
   {
     MOZ_ASSERT(aSeekJob.mTarget->IsAccurate() || aSeekJob.mTarget->IsFast());
     mCurrentTimeBeforeSeek = mMaster->GetMediaTime();
     return SeekingState::Enter(Move(aSeekJob), aVisibility);
   }
 
   void Exit() override
   {
+    if (mSeekJob.Exists() &&
+        mSeekJob.mTarget.isSome() &&
+        mSeekJob.mTarget->IsVideoOnly()) {
+      // We are discarding this video-only seek operation now, and we still need
+      // to dispatch an event so that the UI can change in response to the end
+      // of video-only seek.
+      mMaster->mOnPlaybackEvent.Notify(MediaEventType::VideoOnlySeekCompleted);
+    }
+
     // Disconnect MediaDecoder.
     mSeekJob.RejectIfExists(__func__);
 
     // Disconnect MediaDecoderReaderWrapper.
     mSeekRequest.DisconnectIfExists();
 
     mWaitRequest.DisconnectIfExists();
   }