--- a/dom/media/encoder/MediaEncoder.cpp
+++ b/dom/media/encoder/MediaEncoder.cpp
@@ -28,17 +28,20 @@ mozilla::LazyLogModule gMediaEncoderLog(
 #define LOG(type, msg) MOZ_LOG(gMediaEncoderLog, type, msg)
 
 namespace mozilla {
 
 void
 MediaStreamVideoRecorderSink::SetCurrentFrames(const VideoSegment& aSegment)
 {
   MOZ_ASSERT(mVideoEncoder);
-  mVideoEncoder->SetCurrentFrames(aSegment);
+  // If we're suspended (paused) we don't forward frames
+  if (!mSuspended) {
+    mVideoEncoder->SetCurrentFrames(aSegment);
+  }
 }
 
 void
 MediaEncoder::SetDirectConnect(bool aConnected)
 {
   mDirectConnected = aConnected;
 }
 

--- a/dom/media/encoder/MediaEncoder.h
+++ b/dom/media/encoder/MediaEncoder.h
@@ -19,25 +19,30 @@
 #include "mozilla/Atomics.h"
 
 namespace mozilla {
 
 class MediaStreamVideoRecorderSink : public MediaStreamVideoSink
 {
 public:
   explicit MediaStreamVideoRecorderSink(VideoTrackEncoder* aEncoder)
-    : mVideoEncoder(aEncoder) {}
+    : mVideoEncoder(aEncoder)
+    , mSuspended(false) {}
 
   // MediaStreamVideoSink methods
   virtual void SetCurrentFrames(const VideoSegment& aSegment) override;
   virtual void ClearFrames() override {}
 
+  void Resume() { mSuspended = false; }
+  void Suspend() { mSuspended = true; }
+
 private:
   virtual ~MediaStreamVideoRecorderSink() {}
   VideoTrackEncoder* mVideoEncoder;
+  Atomic<bool> mSuspended;
 };
 
 /**
  * MediaEncoder is the framework of encoding module, it controls and manages
  * procedures between ContainerWriter and TrackEncoder. ContainerWriter packs
  * the encoded track data with a specific container (e.g. ogg, mp4).
  * AudioTrackEncoder and VideoTrackEncoder are subclasses of TrackEncoder, and
  * are responsible for encoding raw data coming from MediaStreamGraph.
@@ -106,28 +111,32 @@ public :
     RECORD_NOT_SUSPENDED,
     RECORD_SUSPENDED,
     RECORD_RESUMED
   };
 
   /* Note - called from control code, not on MSG threads. */
   void Suspend()
   {
+    MOZ_ASSERT(NS_IsMainThread());
     mSuspended = RECORD_SUSPENDED;
+    mVideoSink->Suspend();
   }
 
   /**
    * Note - called from control code, not on MSG threads.
    * Arm to collect the Duration of the next video frame and give it
    * to the next frame, in order to avoid any possible loss of sync. */
   void Resume()
   {
+    MOZ_ASSERT(NS_IsMainThread());
     if (mSuspended == RECORD_SUSPENDED) {
       mSuspended = RECORD_RESUMED;
     }
+    mVideoSink->Resume();
   }
 
   /**
    * Tells us which Notify to pay attention to for media
    */
   void SetDirectConnect(bool aConnected);
 
   /**