--- a/dom/media/webrtc/MediaEngineRemoteVideoSource.cpp
+++ b/dom/media/webrtc/MediaEngineRemoteVideoSource.cpp
@@ -211,20 +211,20 @@ MediaEngineRemoteVideoSource::Allocate(
 
 nsresult
 MediaEngineRemoteVideoSource::Deallocate(const RefPtr<const AllocationHandle>& aHandle)
 {
   LOG((__PRETTY_FUNCTION__));
   AssertIsOnOwningThread();
 
   MOZ_ASSERT(mState == kStopped || mState == kAllocated);
-  MOZ_ASSERT(mStream);
-  MOZ_ASSERT(IsTrackIDExplicit(mTrackID));
 
-  mStream->EndTrack(mTrackID);
+  if (mStream && IsTrackIDExplicit(mTrackID)) {
+    mStream->EndTrack(mTrackID);
+  }
 
   {
     MutexAutoLock lock(mMutex);
 
     mStream = nullptr;
     mTrackID = TRACK_NONE;
     mPrincipal = PRINCIPAL_HANDLE_NONE;
     mState = kReleased;

--- a/dom/media/webrtc/MediaEngineTabVideoSource.cpp
+++ b/dom/media/webrtc/MediaEngineTabVideoSource.cpp
@@ -192,17 +192,19 @@ MediaEngineTabVideoSource::Reconfigure(c
 
 nsresult
 MediaEngineTabVideoSource::Deallocate(const RefPtr<const AllocationHandle>& aHandle)
 {
   AssertIsOnOwningThread();
   MOZ_ASSERT(!aHandle);
   MOZ_ASSERT(mState == kAllocated || mState == kStopped);
 
-  MOZ_ASSERT(IsTrackIDExplicit(mTrackID));
+  if (mStream && IsTrackIDExplicit(mTrackID)) {
+    mStream->EndTrack(mTrackID);
+  }
 
   NS_DispatchToMainThread(do_AddRef(new DestroyRunnable(this)));
 
   {
     MutexAutoLock lock(mMutex);
     mState = kReleased;
   }
 

--- a/dom/media/webrtc/MediaEngineWebRTCAudio.cpp
+++ b/dom/media/webrtc/MediaEngineWebRTCAudio.cpp
@@ -595,17 +595,20 @@ nsresult
 MediaEngineWebRTCMicrophoneSource::Deallocate(const RefPtr<const AllocationHandle>& aHandle)
 {
   AssertIsOnOwningThread();
 
   size_t i = mAllocations.IndexOf(aHandle, 0, AllocationHandleComparator());
   MOZ_ASSERT(i != mAllocations.NoIndex);
   MOZ_ASSERT(!mAllocations[i].mEnabled,
              "Source should be stopped for the track before removing");
-  mAllocations[i].mStream->EndTrack(mAllocations[i].mTrackID);
+  if (mAllocations[i].mStream && IsTrackIDExplicit(mAllocations[i].mTrackID)) {
+    mAllocations[i].mStream->EndTrack(mAllocations[i].mTrackID);
+  }
+
   {
     MutexAutoLock lock(mMutex);
     mAllocations.RemoveElementAt(i);
   }
 
   if (mAllocations.IsEmpty()) {
     // If empty, no callbacks to deliver data should be occuring
     MOZ_ASSERT(mState != kReleased, "Source not allocated");