--- a/dom/locales/en-US/chrome/dom/dom.properties
+++ b/dom/locales/en-US/chrome/dom/dom.properties
@@ -88,16 +88,19 @@ MediaBufferSourceNodeResampleOutOfMemory
 # LOCALIZATION NOTE: Do not translate decodeAudioData.
 MediaDecodeAudioDataUnknownContentType=The buffer passed to decodeAudioData contains an unknown content type.
 # LOCALIZATION NOTE: Do not translate decodeAudioData.
 MediaDecodeAudioDataUnknownError=An unknown error occured while processing decodeAudioData.
 # LOCALIZATION NOTE: Do not translate decodeAudioData.
 MediaDecodeAudioDataInvalidContent=The buffer passed to decodeAudioData contains invalid content which cannot be decoded successfully.
 # LOCALIZATION NOTE: Do not translate decodeAudioData.
 MediaDecodeAudioDataNoAudio=The buffer passed to decodeAudioData does not contain any audio.
+# LOCALIZATION NOTE: Do not translate HTMLMediaElement and createMediaElementAudioSourceNode.
+MediaElementAudioSourceNodeCrossOrigin=The HTMLMediaElement passed to createMediaElementAudioSourceNode has a cross-origin resource, the node will output silence.
+MediaStreamAudioSourceNodeCrossOrigin=The MediaStream passed to createMediaStreamSource has a cross-origin resource, the node it will output silence.
 MediaLoadExhaustedCandidates=All candidate resources failed to load. Media load paused.
 MediaLoadSourceMissingSrc=<source> element has no "src" attribute. Media resource load failed.
 # LOCALIZATION NOTE: %1$S is the Http error code the server returned (e.g. 404, 500, etc), %2$S is the URL of the media resource which failed to load.
 MediaLoadHttpError=HTTP load failed with status %1$S. Load of media resource %2$S failed.
 # LOCALIZATION NOTE: %S is the URL of the media resource which failed to load.
 MediaLoadInvalidURI=Invalid URI. Load of media resource %S failed.
 # LOCALIZATION NOTE: %1$S is the media resource's format/codec type (basically equivalent to the file type, e.g. MP4,AVI,WMV,MOV etc), %2$S is the URL of the media resource which failed to load.
 MediaLoadUnsupportedTypeAttribute=Specified "type" attribute of "%1$S" is not supported. Load of media resource %2$S failed.

--- a/dom/media/webaudio/MediaElementAudioSourceNode.h
+++ b/dom/media/webaudio/MediaElementAudioSourceNode.h
@@ -20,16 +20,21 @@ public:
 
   JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
   const char* NodeType() const override
   {
     return "MediaElementAudioSourceNode";
   }
 
+  const char* CrossOriginErrorString() const override
+  {
+    return "MediaElementAudioSourceNodeCrossOrigin";
+  }
+
   size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override
   {
     return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
   }
 private:
   explicit MediaElementAudioSourceNode(AudioContext* aContext);
 };
 

--- a/dom/media/webaudio/MediaStreamAudioSourceNode.cpp
+++ b/dom/media/webaudio/MediaStreamAudioSourceNode.cpp
@@ -160,29 +160,39 @@ MediaStreamAudioSourceNode::NotifyTrackR
  * change is changing to be the document principal.
  */
 void
 MediaStreamAudioSourceNode::PrincipalChanged(MediaStreamTrack* aMediaStreamTrack)
 {
   MOZ_ASSERT(aMediaStreamTrack == mInputTrack);
 
   bool subsumes = false;
+  nsIDocument* doc = nullptr;
   if (nsPIDOMWindowInner* parent = Context()->GetParentObject()) {
-    nsIDocument* doc = parent->GetExtantDoc();
+    doc = parent->GetExtantDoc();
     if (doc) {
       nsIPrincipal* docPrincipal = doc->NodePrincipal();
       nsIPrincipal* trackPrincipal = aMediaStreamTrack->GetPrincipal();
       if (!trackPrincipal || NS_FAILED(docPrincipal->Subsumes(trackPrincipal, &subsumes))) {
         subsumes = false;
       }
     }
   }
   auto stream = static_cast<AudioNodeExternalInputStream*>(mStream.get());
+  bool enabled = subsumes || aMediaStreamTrack->GetCORSMode() != CORS_NONE;
   stream->SetInt32Parameter(MediaStreamAudioSourceNodeEngine::ENABLE,
-                            subsumes || aMediaStreamTrack->GetCORSMode() != CORS_NONE);
+                            enabled);
+
+  if (!enabled && doc) {
+    nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
+                                    NS_LITERAL_CSTRING("Web Audio"),
+                                    doc,
+                                    nsContentUtils::eDOM_PROPERTIES,
+                                    CrossOriginErrorString());
+  }
 }
 
 size_t
 MediaStreamAudioSourceNode::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
 {
   // Future:
   // - mInputStream
   size_t amount = AudioNode::SizeOfExcludingThis(aMallocSizeOf);

--- a/dom/media/webaudio/MediaStreamAudioSourceNode.h
+++ b/dom/media/webaudio/MediaStreamAudioSourceNode.h
@@ -57,16 +57,21 @@ public:
 
   uint16_t NumberOfInputs() const override { return 0; }
 
   const char* NodeType() const override
   {
     return "MediaStreamAudioSourceNode";
   }
 
+  virtual const char* CrossOriginErrorString() const
+  {
+    return "MediaStreamAudioSourceNodeCrossOrigin";
+  }
+
   size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override;
   size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override;
 
   // Attaches to aTrack so that its audio content will be used as input.
   void AttachToTrack(const RefPtr<MediaStreamTrack>& aTrack);
 
   // Detaches from the currently attached track if there is one.
   void DetachFromTrack();