--- a/dom/media/MediaFormatReader.cpp
+++ b/dom/media/MediaFormatReader.cpp
@@ -377,38 +377,36 @@ MediaFormatReader::OnDemuxerInitDone(nsr
 
 void
 MediaFormatReader::OnDemuxerInitFailed(const MediaResult& aError)
 {
   mDemuxerInitRequest.Complete();
   mMetadataPromise.Reject(aError, __func__);
 }
 
-bool
+MediaResult
 MediaFormatReader::EnsureDecoderCreated(TrackType aTrack)
 {
   MOZ_ASSERT(OnTaskQueue());
   MOZ_DIAGNOSTIC_ASSERT(!IsSuspended());
 
   auto& decoder = GetDecoderData(aTrack);
 
   if (decoder.mDecoder) {
-    return true;
+    return NS_OK;
   }
 
   if (!mPlatform) {
     mPlatform = new PDMFactory();
-    NS_ENSURE_TRUE(mPlatform, false);
     if (IsEncrypted()) {
 #ifdef MOZ_EME
       MOZ_ASSERT(mCDMProxy);
       mPlatform->SetCDMProxy(mCDMProxy);
 #else
-      // EME not supported.
-      return false;
+      return MediaResult(NS_ERROR_DOM_MEDIA_FATAL_ERR, "EME not supported");
 #endif
     }
   }
 
   decoder.mDecoderInitialized = false;
 
   MonitorAutoLock mon(decoder.mMonitor);
 
@@ -438,20 +436,20 @@ MediaFormatReader::EnsureDecoderCreated(
       });
       break;
     }
     default:
       break;
   }
   if (decoder.mDecoder ) {
     decoder.mDescription = decoder.mDecoder->GetDescriptionName();
-  } else {
-    decoder.mDescription = "error creating decoder";
+    return NS_OK;
   }
-  return decoder.mDecoder != nullptr;
+  decoder.mDescription = "error creating decoder";
+  return MediaResult(NS_ERROR_DOM_MEDIA_FATAL_ERR, "error creating decoder");
 }
 
 bool
 MediaFormatReader::EnsureDecoderInitialized(TrackType aTrack)
 {
   MOZ_ASSERT(OnTaskQueue());
   MOZ_DIAGNOSTIC_ASSERT(!IsSuspended());
 
@@ -929,19 +927,20 @@ MediaFormatReader::HandleDemuxedSamples(
   }
 
   auto& decoder = GetDecoderData(aTrack);
 
   if (decoder.mQueuedSamples.IsEmpty()) {
     return;
   }
 
-  if (!EnsureDecoderCreated(aTrack)) {
+  MediaResult rv = EnsureDecoderCreated(aTrack);
+  if (NS_FAILED(rv)) {
     NS_WARNING("Error constructing decoders");
-    NotifyError(aTrack);
+    NotifyError(aTrack, rv);
     return;
   }
 
   if (!EnsureDecoderInitialized(aTrack)) {
     return;
   }
 
   if (!ForceZeroStartTime() && decoder.mFirstDemuxedSampleTime.isNothing()) {

--- a/dom/media/MediaFormatReader.h
+++ b/dom/media/MediaFormatReader.h
@@ -112,17 +112,17 @@ private:
 
   bool InitDemuxer();
   // Notify the demuxer that new data has been received.
   // The next queued task calling GetBuffered() is guaranteed to have up to date
   // buffered ranges.
   void NotifyDemuxer();
   void ReturnOutput(MediaData* aData, TrackType aTrack);
 
-  bool EnsureDecoderCreated(TrackType aTrack);
+  MediaResult EnsureDecoderCreated(TrackType aTrack);
   bool EnsureDecoderInitialized(TrackType aTrack);
 
   // Enqueues a task to call Update(aTrack) on the decoder task queue.
   // Lock for corresponding track must be held.
   void ScheduleUpdate(TrackType aTrack);
   void Update(TrackType aTrack);
   // Handle actions should more data be received.
   // Returns true if no more action is required.
@@ -161,18 +161,17 @@ private:
   // the first sample past the target will be dropped.
   void InternalSeek(TrackType aTrack, const InternalSeekTarget& aTarget);
 
   // Drain the current decoder.
   void DrainDecoder(TrackType aTrack);
   void NotifyNewOutput(TrackType aTrack, MediaData* aSample);
   void NotifyInputExhausted(TrackType aTrack);
   void NotifyDrainComplete(TrackType aTrack);
-  void NotifyError(TrackType aTrack,
-                   const MediaResult& aError = MediaResult(NS_ERROR_DOM_MEDIA_FATAL_ERR));
+  void NotifyError(TrackType aTrack, const MediaResult& aError);
   void NotifyWaitingForData(TrackType aTrack);
   void NotifyEndOfStream(TrackType aTrack);
 
   void ExtractCryptoInitData(nsTArray<uint8_t>& aInitData);
 
   // Initializes mLayersBackendType if possible.
   void InitLayersBackendType();