--- a/dom/html/HTMLMediaElement.cpp
+++ b/dom/html/HTMLMediaElement.cpp
@@ -2288,25 +2288,28 @@ void HTMLMediaElement::NotifyMediaTrackE
       return;
     }
     mDisableVideo = false;
   } else {
     MOZ_ASSERT(false, "Unknown track type");
   }
 
   if (mSrcStream) {
-    MOZ_ASSERT(mMediaStreamRenderer);
     if (AudioTrack* t = aTrack->AsAudioTrack()) {
-      mMediaStreamRenderer->AddTrack(t->GetAudioStreamTrack());
+      if (mMediaStreamRenderer) {
+        mMediaStreamRenderer->AddTrack(t->GetAudioStreamTrack());
+      }
     } else if (VideoTrack* t = aTrack->AsVideoTrack()) {
       MOZ_ASSERT(!mSelectedVideoStreamTrack);
 
       mSelectedVideoStreamTrack = t->GetVideoStreamTrack();
       mSelectedVideoStreamTrack->AddPrincipalChangeObserver(this);
-      mMediaStreamRenderer->AddTrack(mSelectedVideoStreamTrack);
+      if (mMediaStreamRenderer) {
+        mMediaStreamRenderer->AddTrack(mSelectedVideoStreamTrack);
+      }
       nsContentUtils::CombineResourcePrincipals(
           &mSrcStreamVideoPrincipal, mSelectedVideoStreamTrack->GetPrincipal());
       if (VideoFrameContainer* container = GetVideoFrameContainer()) {
         HTMLVideoElement* self = static_cast<HTMLVideoElement*>(this);
         if (mSrcStreamIsPlaying) {
           MaybeBeginCloningVisually();
         } else if (self->VideoWidth() <= 1 && self->VideoHeight() <= 1) {
           // MediaInfo uses dummy values of 1 for width and height to
@@ -2348,18 +2351,20 @@ void HTMLMediaElement::NotifyMediaTrackD
                         aTrack->AsAudioTrack() ? "Audio" : "Video",
                         NS_ConvertUTF16toUTF8(id).get()));
 #endif
 
   MOZ_ASSERT((!aTrack->AsAudioTrack() || !aTrack->AsAudioTrack()->Enabled()) &&
              (!aTrack->AsVideoTrack() || !aTrack->AsVideoTrack()->Selected()));
 
   if (AudioTrack* t = aTrack->AsAudioTrack()) {
-    if (mMediaStreamRenderer) {
-      mMediaStreamRenderer->RemoveTrack(t->GetAudioStreamTrack());
+    if (mSrcStream) {
+      if (mMediaStreamRenderer) {
+        mMediaStreamRenderer->RemoveTrack(t->GetAudioStreamTrack());
+      }
     }
     // If we don't have any live tracks, we don't need to mute MediaElement.
     MOZ_DIAGNOSTIC_ASSERT(AudioTracks(), "Element can't have been unlinked");
     if (AudioTracks()->Length() > 0) {
       bool shouldMute = true;
       for (uint32_t i = 0; i < AudioTracks()->Length(); ++i) {
         if ((*AudioTracks())[i]->Enabled()) {
           shouldMute = false;
@@ -2367,24 +2372,26 @@ void HTMLMediaElement::NotifyMediaTrackD
         }
       }
 
       if (shouldMute) {
         SetMutedInternal(mMuted | MUTED_BY_AUDIO_TRACK);
       }
     }
   } else if (aTrack->AsVideoTrack()) {
-    if (mMediaStreamRenderer) {
+    if (mSrcStream) {
       MOZ_DIAGNOSTIC_ASSERT(mSelectedVideoStreamTrack ==
                             aTrack->AsVideoTrack()->GetVideoStreamTrack());
       if (mFirstFrameListener) {
         mSelectedVideoStreamTrack->RemoveVideoOutput(mFirstFrameListener);
         mFirstFrameListener = nullptr;
       }
-      mMediaStreamRenderer->RemoveTrack(mSelectedVideoStreamTrack);
+      if (mMediaStreamRenderer) {
+        mMediaStreamRenderer->RemoveTrack(mSelectedVideoStreamTrack);
+      }
       mSelectedVideoStreamTrack->RemovePrincipalChangeObserver(this);
       mSelectedVideoStreamTrack = nullptr;
     }
   }
 
   if (mReadyState == HAVE_NOTHING) {
     // No MediaStreamTracks are captured until we have metadata, and code
     // below doesn't do anything for captured decoders.
@@ -4809,33 +4816,38 @@ void HTMLMediaElement::UpdateSrcMediaStr
 
   LOG(LogLevel::Debug,
       ("MediaElement %p %s playback of DOMMediaStream %p", this,
        shouldPlay ? "Setting up" : "Removing", mSrcStream.get()));
 
   if (shouldPlay) {
     mSrcStreamPlaybackEnded = false;
 
-    mMediaStreamRenderer->Start();
+    if (mMediaStreamRenderer) {
+      mMediaStreamRenderer->Start();
+    }
+
     if (mSink.second()) {
       NS_WARNING(
           "setSinkId() when playing a MediaStream is not supported yet and "
           "will be ignored");
     }
 
     if (mSelectedVideoStreamTrack && GetVideoFrameContainer()) {
       MaybeBeginCloningVisually();
     }
 
     SetCapturedOutputStreamsEnabled(true);  // Unmute
     // If the input is a media stream, we don't check its data and always regard
     // it as audible when it's playing.
     SetAudibleState(true);
   } else {
-    mMediaStreamRenderer->Stop();
+    if (mMediaStreamRenderer) {
+      mMediaStreamRenderer->Stop();
+    }
     VideoFrameContainer* container = GetVideoFrameContainer();
     if (mSelectedVideoStreamTrack && container) {
       HTMLVideoElement* self = static_cast<HTMLVideoElement*>(this);
       if (self->VideoWidth() <= 1 && self->VideoHeight() <= 1) {
         // MediaInfo uses dummy values of 1 for width and height to
         // mark video as valid. We need a new first-frame listener
         // if size is 0x0 or 1x1.
         if (!mFirstFrameListener) {