--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -776,17 +776,21 @@ MediaDecoderStateMachine::OnNotDecoded(M
     MOZ_ASSERT(mReader->IsWaitForDataSupported(),
                "Readers that send WAITING_FOR_DATA need to implement WaitForData");
     RefPtr<MediaDecoderStateMachine> self = this;
     WaitRequestRef(aType).Begin(InvokeAsync(DecodeTaskQueue(), mReader.get(), __func__,
                                             &MediaDecoderReader::WaitForData, aType)
       ->Then(OwnerThread(), __func__,
              [self] (MediaData::Type aType) -> void {
                self->WaitRequestRef(aType).Complete();
-               self->DispatchDecodeTasksIfNeeded();
+               if (aType == MediaData::AUDIO_DATA) {
+                 self->EnsureAudioDecodeTaskQueued();
+               } else {
+                 self->EnsureVideoDecodeTaskQueued();
+               }
              },
              [self] (WaitForDataRejectValue aRejection) -> void {
                self->WaitRequestRef(aRejection.mType).Complete();
              }));
 
     // We are out of data to decode and will enter buffering mode soon.
     // We want to play the frames we have already decoded, so we stop pre-rolling
     // and ensure that loadeddata is fired as required.
@@ -797,17 +801,21 @@ MediaDecoderStateMachine::OnNotDecoded(M
     }
     if (mState == DECODER_STATE_BUFFERING || mState == DECODER_STATE_DECODING) {
         MaybeFinishDecodeFirstFrame();
     }
     return;
   }
 
   if (aReason == MediaDecoderReader::CANCELED) {
-    DispatchDecodeTasksIfNeeded();
+    if (isAudio) {
+      EnsureAudioDecodeTaskQueued();
+    } else {
+      EnsureVideoDecodeTaskQueued();
+    }
     return;
   }
 
   // This is an EOS. Finish off the queue, and then handle things based on our
   // state.
   MOZ_ASSERT(aReason == MediaDecoderReader::END_OF_STREAM);
   if (!isAudio && mState == DECODER_STATE_SEEKING &&
       mCurrentSeek.Exists() && mFirstVideoFrameAfterSeek) {