Bug 1053186 - AudioOffloadPlayer: Avoid glitch during start of playback. r=roc

content/media/AbstractMediaDecoder.h

@@ -119,8 +119,11 @@ public:
   // required to begin playback have been acquired. Can be called on any thread.
   virtual void NotifyWaitingForResourcesStatusChanged() = 0;
 
-  // Called by Reader if the current audio track can be offloaded
-  virtual void SetCanOffloadAudio(bool aCanOffloadAudio) {}
+  // Set by Reader if the current audio track can be offloaded
+  virtual void SetPlatformCanOffloadAudio(bool aCanOffloadAudio) {}
+
+  // Called by Decoder/State machine to check audio offload condtions are met
+  virtual bool CheckDecoderCanOffloadAudio() { return false; }
 
   // Called from HTMLMediaElement when owner document activity changes
   virtual void SetElementVisibility(bool aIsVisible) {}

content/media/MediaDecoderStateMachine.cpp

@@ -1135,6 +1135,11 @@ void MediaDecoderStateMachine::StartPlayback()
   NS_ASSERTION(!IsPlaying(), "Shouldn't be playing when StartPlayback() is called");
   AssertCurrentThreadInMonitor();
 
+  if (mDecoder->CheckDecoderCanOffloadAudio()) {
+    DECODER_LOG(PR_LOG_DEBUG, "Offloading playback");
+    return;
+  }
+
   mDecoder->NotifyPlaybackStarted();
   SetPlayStartTime(TimeStamp::Now());
 

content/media/omx/MediaOmxCommonDecoder.cpp

@@ -41,12 +41,19 @@ MediaOmxCommonDecoder::MediaOmxCommonDecoder()
 }
 
 void
-MediaOmxCommonDecoder::SetCanOffloadAudio(bool aCanOffloadAudio)
+MediaOmxCommonDecoder::SetPlatformCanOffloadAudio(bool aCanOffloadAudio)
 {
   ReentrantMonitorAutoEnter mon(GetReentrantMonitor());
   mCanOffloadAudio = aCanOffloadAudio;
 }
 
+bool
+MediaOmxCommonDecoder::CheckDecoderCanOffloadAudio()
+{
+  return (mCanOffloadAudio && !mFallbackToStateMachine && !mOutputStreams.Length() &&
+      mInitialPlaybackRate == 1.0);
+}
+
 void
 MediaOmxCommonDecoder::MetadataLoaded(MediaInfo* aInfo,
                                       MetadataTags* aTags)
@@ -55,8 +62,7 @@ MediaOmxCommonDecoder::MetadataLoaded(MediaInfo* aInfo,
   MediaDecoder::MetadataLoaded(aInfo, aTags);
 
   ReentrantMonitorAutoEnter mon(GetReentrantMonitor());
-  if (!mCanOffloadAudio || mFallbackToStateMachine || mOutputStreams.Length() ||
-      mInitialPlaybackRate != 1.0) {
+  if (!CheckDecoderCanOffloadAudio()) {
     DECODER_LOG(PR_LOG_DEBUG, ("In %s Offload Audio check failed",
         __PRETTY_FUNCTION__));
     return;
@@ -79,6 +85,7 @@ MediaOmxCommonDecoder::MetadataLoaded(MediaInfo* aInfo,
   }
 
   mAudioOffloadPlayer = nullptr;
+  mFallbackToStateMachine = true;
   DECODER_LOG(PR_LOG_DEBUG, ("In %s Unable to start offload audio %d."
       "Switching to normal mode", __PRETTY_FUNCTION__, err));
 }

content/media/omx/MediaOmxCommonDecoder.h

@@ -31,7 +31,8 @@ public:
   virtual void PlaybackPositionChanged();
   virtual void UpdateReadyStateForData();
   virtual void SetElementVisibility(bool aIsVisible);
-  virtual void SetCanOffloadAudio(bool aCanOffloadAudio);
+  virtual void SetPlatformCanOffloadAudio(bool aCanOffloadAudio);
+  virtual bool CheckDecoderCanOffloadAudio();
   virtual void AddOutputStream(ProcessedMediaStream* aStream,
                                bool aFinishWhenEnded);
   virtual void SetPlaybackRate(double aPlaybackRate);

content/media/omx/MediaOmxCommonReader.cpp

@@ -73,7 +73,7 @@ void MediaOmxCommonReader::CheckAudioOffload()
   if ((meta.get()) && hasNoVideo && isNotStreaming && isTypeMusic &&
       canOffloadStream(meta, false, false, AUDIO_STREAM_MUSIC)) {
     DECODER_LOG(PR_LOG_DEBUG, ("Can offload this audio stream"));
-    mDecoder->SetCanOffloadAudio(true);
+    mDecoder->SetPlatformCanOffloadAudio(true);
   }
 }
 #endif