Bug 1274626 part 5 - provide APIs to switch to blank decoders dynamically; r=jya

MozReview-Commit-ID: PyoIsrEf1r

--HG--
extra : transplant_source : C%D6%9E%89%E2O%DB%DFb%A8%9Az%1FE%11%06oo%EE%3C

dom/media/MediaDecoderReader.h

@@ -317,6 +317,11 @@ public:
     return &mIsSuspended;
   }
 
+  // Switch the video decoder to BlankDecoderModule. It might takes effective
+  // since a few samples later depends on how much demuxed samples are already
+  // queued in the original video decoder.
+  virtual void SetVideoBlankDecode(bool aIsBlankDecode) {}
+
 protected:
   virtual ~MediaDecoderReader();
 

dom/media/MediaDecoderReaderWrapper.cpp

@@ -410,4 +410,14 @@ MediaDecoderReaderWrapper::OnMetadataRead(MetadataHolder* aMetadata)
   }
 }
 
+void
+MediaDecoderReaderWrapper::SetVideoBlankDecode(bool aIsBlankDecode)
+{
+  MOZ_ASSERT(mOwnerThread->IsCurrentThreadIn());
+  nsCOMPtr<nsIRunnable> r =
+    NewRunnableMethod<bool>(mReader, &MediaDecoderReader::SetVideoBlankDecode,
+                            aIsBlankDecode);
+  mReader->OwnerThread()->Dispatch(r.forget());
+}
+
 } // namespace mozilla

dom/media/MediaDecoderReaderWrapper.h

@@ -121,6 +121,8 @@ public:
   void SetCDMProxy(CDMProxy* aProxy) { mReader->SetCDMProxy(aProxy); }
 #endif
 
+  void SetVideoBlankDecode(bool aIsBlankDecode);
+
 private:
   ~MediaDecoderReaderWrapper();
 

dom/media/MediaFormatReader.cpp

@@ -418,7 +418,8 @@ MediaFormatReader::EnsureDecoderCreated(TrackType aTrack)
         decoder.mInfo ? *decoder.mInfo->GetAsAudioInfo() : mInfo.mAudio,
         decoder.mTaskQueue,
         decoder.mCallback.get(),
-        mCrashHelper
+        mCrashHelper,
+        decoder.mIsBlankDecode
       });
       break;
     }
@@ -432,7 +433,8 @@ MediaFormatReader::EnsureDecoderCreated(TrackType aTrack)
         decoder.mCallback.get(),
         mLayersBackendType,
         GetImageContainer(),
-        mCrashHelper
+        mCrashHelper,
+        decoder.mIsBlankDecode
       });
       break;
     }
@@ -2060,4 +2062,32 @@ MediaFormatReader::GetMozDebugReaderData(nsAString& aString)
   aString += NS_ConvertUTF8toUTF16(result);
 }
 
+void
+MediaFormatReader::SetVideoBlankDecode(bool aIsBlankDecode)
+{
+  MOZ_ASSERT(OnTaskQueue());
+  return SetBlankDecode(TrackType::kVideoTrack, aIsBlankDecode);
+}
+
+void
+MediaFormatReader::SetBlankDecode(TrackType aTrack, bool aIsBlankDecode)
+{
+  MOZ_ASSERT(OnTaskQueue());
+  auto& decoder = GetDecoderData(aTrack);
+
+  LOG("%s, decoder.mIsBlankDecode = %d => aIsBlankDecode = %d",
+      TrackTypeToStr(aTrack), decoder.mIsBlankDecode, aIsBlankDecode);
+
+  if (decoder.mIsBlankDecode == aIsBlankDecode) {
+    return;
+  }
+
+  decoder.mIsBlankDecode = aIsBlankDecode;
+  decoder.Flush();
+  decoder.ShutdownDecoder();
+  NotifyDecodingRequested(TrackInfo::kVideoTrack); // Calls ScheduleUpdate().
+
+  return;
+}
+
 } // namespace mozilla

dom/media/MediaFormatReader.h

@@ -101,6 +101,8 @@ public:
   // Used for debugging purposes.
   void GetMozDebugReaderData(nsAString& aString);
 
+  void SetVideoBlankDecode(bool aIsBlankDecode) override;
+
 private:
 
   bool HasVideo() { return mVideo.mTrackDemuxer; }
@@ -253,6 +255,7 @@ private:
       , mSizeOfQueue(0)
       , mIsHardwareAccelerated(false)
       , mLastStreamSourceID(UINT32_MAX)
+      , mIsBlankDecode(false)
     {}
 
     MediaFormatReader* mOwner;
@@ -427,6 +430,9 @@ private:
     Maybe<media::TimeUnit> mLastTimeRangesEnd;
     RefPtr<SharedTrackInfo> mInfo;
     Maybe<media::TimeUnit> mFirstDemuxedSampleTime;
+    // Use BlankDecoderModule or not.
+    bool mIsBlankDecode;
+
   };
 
   class DecoderDataWithPromise : public DecoderData {
@@ -571,6 +577,8 @@ private:
   RefPtr<CDMProxy> mCDMProxy;
 #endif
   RefPtr<GMPCrashHelper> mCrashHelper;
+
+  void SetBlankDecode(TrackType aTrack, bool aIsBlankDecode);
 };
 
 } // namespace mozilla