--- a/dom/media/mediasink/DecodedStream.cpp
+++ b/dom/media/mediasink/DecodedStream.cpp
@@ -16,16 +16,19 @@
 #include "MediaStreamListener.h"
 #include "OutputStreamManager.h"
 #include "SharedBuffer.h"
 #include "VideoSegment.h"
 #include "VideoUtils.h"
 
 namespace mozilla {
 
+#undef DUMP_LOG
+#define DUMP_LOG(x, ...) NS_DebugBreak(NS_DEBUG_WARNING, nsPrintfCString(x, ##__VA_ARGS__).get(), nullptr, nullptr, -1)
+
 /*
  * A container class to make it easier to pass the playback info all the
  * way to DecodedStreamGraphListener from DecodedStream.
  */
 struct PlaybackInfoInit {
   int64_t mStartTime;
   MediaInfo mInfo;
 };
@@ -122,16 +125,17 @@ class DecodedStreamData {
 public:
   DecodedStreamData(OutputStreamManager* aOutputStreamManager,
                     PlaybackInfoInit&& aInit,
                     MozPromiseHolder<GenericPromise>&& aPromise);
   ~DecodedStreamData();
   void SetPlaying(bool aPlaying);
   MediaEventSource<int64_t>& OnOutput();
   void Forget();
+  void DumpDebugInfo();
 
   /* The following group of fields are protected by the decoder's monitor
    * and can be read or written on any thread.
    */
   // Count of audio frames written to the stream
   int64_t mAudioFramesWritten;
   // mNextVideoTime is the end timestamp for the last packet sent to the stream.
   // Therefore video packets starting at or after this time need to be copied
@@ -211,16 +215,27 @@ DecodedStreamData::SetPlaying(bool aPlay
 }
 
 void
 DecodedStreamData::Forget()
 {
   mListener->Forget();
 }
 
+void
+DecodedStreamData::DumpDebugInfo()
+{
+  DUMP_LOG(
+    "DecodedStreamData=%p mPlaying=%d mAudioFramesWritten=%lld"
+    "mNextAudioTime=%lld mNextVideoTime=%lld mHaveSentFinish=%d"
+    "mHaveSentFinishAudio=%d mHaveSentFinishVideo=%d",
+    this, mPlaying, mAudioFramesWritten, mNextAudioTime, mNextVideoTime,
+    mHaveSentFinish, mHaveSentFinishAudio, mHaveSentFinishVideo);
+}
+
 DecodedStream::DecodedStream(AbstractThread* aOwnerThread,
                              MediaQueue<MediaData>& aAudioQueue,
                              MediaQueue<MediaData>& aVideoQueue,
                              OutputStreamManager* aOutputStreamManager,
                              const bool& aSameOrigin,
                              const PrincipalHandle& aPrincipalHandle)
   : mOwnerThread(aOwnerThread)
   , mOutputStreamManager(aOutputStreamManager)
@@ -744,9 +759,21 @@ DecodedStream::DisconnectListener()
   AssertOwnerThread();
 
   mAudioPushListener.Disconnect();
   mVideoPushListener.Disconnect();
   mAudioFinishListener.Disconnect();
   mVideoFinishListener.Disconnect();
 }
 
+void
+DecodedStream::DumpDebugInfo()
+{
+  AssertOwnerThread();
+  DUMP_LOG(
+    "DecodedStream=%p mStartTime=%lld mLastOutputTime=%lld mPlaying=%d mData=%p",
+    this, mStartTime.valueOr(-1), mLastOutputTime, mPlaying, mData.get());
+  if (mData) {
+    mData->DumpDebugInfo();
+  }
+}
+
 } // namespace mozilla

--- a/dom/media/mediasink/DecodedStream.h
+++ b/dom/media/mediasink/DecodedStream.h
@@ -58,16 +58,18 @@ public:
   void SetPreservesPitch(bool aPreservesPitch) override;
   void SetPlaying(bool aPlaying) override;
 
   void Start(int64_t aStartTime, const MediaInfo& aInfo) override;
   void Stop() override;
   bool IsStarted() const override;
   bool IsPlaying() const override;
 
+  void DumpDebugInfo() override;
+
 protected:
   virtual ~DecodedStream();
 
 private:
   void DestroyData(UniquePtr<DecodedStreamData> aData);
   void AdvanceTracks();
   void SendAudio(double aVolume, bool aIsSameOrigin, const PrincipalHandle& aPrincipalHandle);
   void SendVideo(bool aIsSameOrigin, const PrincipalHandle& aPrincipalHandle);

--- a/dom/media/mediasink/VideoSink.cpp
+++ b/dom/media/mediasink/VideoSink.cpp
@@ -469,12 +469,13 @@ VideoSink::DumpDebugInfo()
 {
   AssertOwnerThread();
   DUMP_LOG(
     "IsStarted=%d IsPlaying=%d, VideoQueue: finished=%d size=%d, "
     "mVideoFrameEndTime=%lld mHasVideo=%d mVideoSinkEndRequest.Exists()=%d "
     "mEndPromiseHolder.IsEmpty()=%d",
     IsStarted(), IsPlaying(), VideoQueue().IsFinished(), VideoQueue().GetSize(),
     mVideoFrameEndTime, mHasVideo, mVideoSinkEndRequest.Exists(), mEndPromiseHolder.IsEmpty());
+  mAudioSink->DumpDebugInfo();
 }
 
 } // namespace media
 } // namespace mozilla

--- a/dom/media/test/test_bug1113600.html
+++ b/dom/media/test/test_bug1113600.html
@@ -4,16 +4,18 @@
   <title>Test that a video element captured to a stream mid-playback can be played to the end</title>
   <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
   <script type="text/javascript" src="manifest.js"></script>
 </head>
 <body>
 <pre id="test">
 <script class="testbody" type="text/javascript">
+PARALLEL_TESTS = 1;
+SimpleTest.requestCompleteLog();
 var manager = new MediaTestManager;
 
 function startTest(test, token) {
   var v = document.createElement('video');
   v.style = "background-color:#aca;";
   v.width = 160;
   v.height = 120;