--- a/dom/media/MediaPrefs.h
+++ b/dom/media/MediaPrefs.h
@@ -87,16 +87,19 @@ private:
   // This is where DECL_MEDIA_PREF for each of the preferences should go.
 
   // AudioSink
   DECL_MEDIA_PREF("accessibility.monoaudio.enable",           MonoAudio, bool, false);
   DECL_MEDIA_PREF("media.resampling.enabled",                 AudioSinkResampling, bool, false);
   DECL_MEDIA_PREF("media.resampling.rate",                    AudioSinkResampleRate, uint32_t, 48000);
   DECL_MEDIA_PREF("media.forcestereo.enabled",                AudioSinkForceStereo, bool, true);
 
+  // VideoSink
+  DECL_MEDIA_PREF("media.ruin-av-sync.enabled",               RuinAvSync, bool, false);
+
   // PlatformDecoderModule
   DECL_MEDIA_PREF("media.apple.forcevda",                     AppleForceVDA, bool, false);
   DECL_MEDIA_PREF("media.gmp.insecure.allow",                 GMPAllowInsecure, bool, false);
   DECL_MEDIA_PREF("media.gmp.async-shutdown-timeout",         GMPAsyncShutdownTimeout, uint32_t, GMP_DEFAULT_ASYNC_SHUTDOWN_TIMEOUT);
   DECL_MEDIA_PREF("media.eme.enabled",                        EMEEnabled, bool, false);
   DECL_MEDIA_PREF("media.use-blank-decoder",                  PDMUseBlankDecoder, bool, false);
 #ifdef MOZ_GONK_MEDIACODEC
   DECL_MEDIA_PREF("media.gonk.enabled",                       PDMGonkDecoderEnabled, bool, true);

--- a/dom/media/mediasink/VideoSink.cpp
+++ b/dom/media/mediasink/VideoSink.cpp
@@ -1,16 +1,17 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "MediaQueue.h"
 #include "VideoSink.h"
+#include "MediaPrefs.h"
 
 namespace mozilla {
 
 extern LazyLogModule gMediaDecoderLog;
 #define VSINK_LOG(msg, ...) \
   MOZ_LOG(gMediaDecoderLog, LogLevel::Debug, \
     ("VideoSink=%p " msg, this, ##__VA_ARGS__))
 #define VSINK_LOG_V(msg, ...) \
@@ -32,16 +33,17 @@ VideoSink::VideoSink(AbstractThread* aTh
   , mVideoQueue(aVideoQueue)
   , mContainer(aContainer)
   , mProducerID(ImageContainer::AllocateProducerID())
   , mFrameStats(aFrameStats)
   , mVideoFrameEndTime(-1)
   , mHasVideo(false)
   , mUpdateScheduler(aThread)
   , mVideoQueueSendToCompositorSize(aVQueueSentToCompositerSize)
+  , mMinVideoQueueSize(MediaPrefs::RuinAvSync() ? 1 : 0)
 {
   MOZ_ASSERT(mAudioSink, "AudioSink should exist.");
 }
 
 VideoSink::~VideoSink()
 {
 }
 
@@ -389,17 +391,17 @@ VideoSink::UpdateRenderedVideoFrames()
 
   // Get the current playback position.
   TimeStamp nowTime;
   const int64_t clockTime = mAudioSink->GetPosition(&nowTime);
   NS_ASSERTION(clockTime >= 0, "Should have positive clock time.");
 
   // Skip frames up to the playback position.
   int64_t lastDisplayedFrameEndTime = 0;
-  while (VideoQueue().GetSize() > 0 &&
+  while (VideoQueue().GetSize() > mMinVideoQueueSize &&
          clockTime > VideoQueue().PeekFront()->GetEndTime()) {
     RefPtr<MediaData> frame = VideoQueue().PopFront();
     if (frame->As<VideoData>()->mSentToCompositor) {
       lastDisplayedFrameEndTime = frame->GetEndTime();
       mFrameStats.NotifyPresentedFrame();
     } else {
       mFrameStats.NotifyDecodedFrames({ 0, 0, 1 });
       VSINK_LOG_V("discarding video frame mTime=%lld clock_time=%lld",

--- a/dom/media/mediasink/VideoSink.h
+++ b/dom/media/mediasink/VideoSink.h
@@ -134,14 +134,23 @@ private:
   bool mHasVideo;
 
   // Used to trigger another update of rendered frames in next round.
   DelayedScheduler mUpdateScheduler;
 
   // Max frame number sent to compositor at a time.
   // Based on the pref value obtained in MDSM.
   const uint32_t mVideoQueueSendToCompositorSize;
+
+  // Talos tests for the compositor require at least one frame in the
+  // video queue so that the compositor has something to composit during
+  // the talos test when the decode is stressed. We have a minimum size
+  // on the video queue in order to facilitate this talos test.
+  // Note: Normal playback should not have a queue size of more than 0,
+  // otherwise A/V sync will be ruined! *Only* make this non-zero for
+  // testing purposes.
+  const uint32_t mMinVideoQueueSize;
 };
 
 } // namespace media
 } // namespace mozilla
 
 #endif