Bug 1062669 - Consider only SourceBuffers created before the first initialization segment is appended as essential for parent decoder initialization. r=cajbir

content/media/mediasource/MediaSource.cpp

@@ -339,6 +339,7 @@ MediaSource::Detach()
   }
   mDecoder->DetachMediaSource();
   mDecoder = nullptr;
+  mFirstSourceBufferInitialization = false;
   SetReadyState(MediaSourceReadyState::Closed);
   mDuration = UnspecifiedNaN<double>();
   if (mActiveSourceBuffers) {
@@ -395,6 +396,7 @@ MediaSource::MediaSource(nsPIDOMWindow* aWindow)
   , mDuration(UnspecifiedNaN<double>())
   , mDecoder(nullptr)
   , mReadyState(MediaSourceReadyState::Closed)
+  , mFirstSourceBufferInitialization(false)
 {
   MOZ_ASSERT(NS_IsMainThread());
   mSourceBuffers = new SourceBufferList(this);
@@ -482,6 +484,29 @@ MediaSource::NotifyEvicted(double aStart, double aEnd)
   mSourceBuffers->Evict(aStart, aEnd);
 }
 
+void
+MediaSource::QueueInitializationEvent()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  if (!mFirstSourceBufferInitialization) {
+    mFirstSourceBufferInitialization = true;
+  }
+  MSE_DEBUG("MediaSource(%p)::QueueInitializationEvent()", this);
+  nsRefPtr<nsIRunnable> task =
+    NS_NewRunnableMethod(this, &MediaSource::InitializationEvent);
+  NS_DispatchToMainThread(task);
+}
+
+void
+MediaSource::InitializationEvent()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MSE_DEBUG("MediaSource(%p)::InitializationEvent()", this);
+  if (mDecoder) {
+    mDecoder->PrepareReaderInitialization();
+  }
+}
+
 nsPIDOMWindow*
 MediaSource::GetParentObject() const
 {

content/media/mediasource/MediaSource.h

@@ -90,6 +90,14 @@ public:
   // that were evicted are provided.
   void NotifyEvicted(double aStart, double aEnd);
 
+  // Queue InitializationEvent to run on the main thread.  Called when a
+  // SourceBuffer has an initialization segment appended, but only
+  // dispatched the first time (using mFirstSourceBufferInitialization).
+  // Demarcates the point in time at which only currently registered
+  // TrackBuffers are treated as essential by the MediaSourceReader for
+  // initialization.
+  void QueueInitializationEvent();
+
 private:
   ~MediaSource();
 
@@ -101,6 +109,8 @@ private:
 
   void DurationChange(double aNewDuration, ErrorResult& aRv);
 
+  void InitializationEvent();
+
   double mDuration;
 
   nsRefPtr<SourceBufferList> mSourceBuffers;
@@ -109,6 +119,8 @@ private:
   nsRefPtr<MediaSourceDecoder> mDecoder;
 
   MediaSourceReadyState mReadyState;
+
+  bool mFirstSourceBufferInitialization;
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(MediaSource, MOZILLA_DOM_MEDIASOURCE_IMPLEMENTATION_IID)

content/media/mediasource/MediaSourceDecoder.cpp

@@ -188,4 +188,11 @@ MediaSourceDecoder::NotifyGotData()
   mon.NotifyAll();
 }
 
+void
+MediaSourceDecoder::PrepareReaderInitialization()
+{
+  MOZ_ASSERT(mReader);
+  mReader->PrepareInitialization();
+}
+
 } // namespace mozilla

content/media/mediasource/MediaSourceDecoder.h

@@ -61,6 +61,10 @@ public:
   // Called whenever a SourceBuffer has new data appended.
   void NotifyGotData();
 
+  // Indicates the point in time at which the reader should consider
+  // registered TrackBuffers essential for initialization.
+  void PrepareReaderInitialization();
+
 private:
   // The owning MediaSource holds a strong reference to this decoder, and
   // calls Attach/DetachMediaSource on this decoder to set and clear

content/media/mediasource/MediaSourceReader.cpp

@@ -46,19 +46,33 @@ MediaSourceReader::MediaSourceReader(MediaSourceDecoder* aDecoder)
   , mEnded(false)
   , mAudioIsSeeking(false)
   , mVideoIsSeeking(false)
+  , mHasEssentialTrackBuffers(false)
 {
 }
 
+void
+MediaSourceReader::PrepareInitialization()
+{
+  ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
+  MSE_DEBUG("MediaSourceReader(%p)::PrepareInitialization trackBuffers=%u",
+            this, mTrackBuffers.Length());
+  mEssentialTrackBuffers.AppendElements(mTrackBuffers);
+  mHasEssentialTrackBuffers = true;
+  mDecoder->NotifyWaitingForResourcesStatusChanged();
+}
+
 bool
 MediaSourceReader::IsWaitingMediaResources()
 {
   ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
-  for (uint32_t i = 0; i < mTrackBuffers.Length(); ++i) {
-    if (!mTrackBuffers[i]->IsReady()) {
+
+  for (uint32_t i = 0; i < mEssentialTrackBuffers.Length(); ++i) {
+    if (!mEssentialTrackBuffers[i]->IsReady()) {
       return true;
     }
   }
-  return mTrackBuffers.IsEmpty();
+
+  return !mHasEssentialTrackBuffers;
 }
 
 void
@@ -367,6 +381,7 @@ void
 MediaSourceReader::OnTrackBufferConfigured(TrackBuffer* aTrackBuffer, const MediaInfo& aInfo)
 {
   ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
+  MOZ_ASSERT(aTrackBuffer->IsReady());
   MOZ_ASSERT(mTrackBuffers.Contains(aTrackBuffer));
   if (aInfo.HasAudio() && !mAudioTrack) {
     MSE_DEBUG("MediaSourceReader(%p)::OnTrackBufferConfigured %p audio", this, aTrackBuffer);
@@ -472,11 +487,15 @@ MediaSourceReader::Seek(int64_t aTime, int64_t aStartTime, int64_t aEndTime,
 nsresult
 MediaSourceReader::ReadMetadata(MediaInfo* aInfo, MetadataTags** aTags)
 {
-  MSE_DEBUG("MediaSourceReader(%p)::ReadMetadata tracks=%u", this, mTrackBuffers.Length());
+  bool waiting = IsWaitingMediaResources();
+  MSE_DEBUG("MediaSourceReader(%p)::ReadMetadata waiting=%d tracks=%u/%u audio=%p video=%p",
+            this, waiting, mEssentialTrackBuffers.Length(), mTrackBuffers.Length(),
+            mAudioTrack.get(), mVideoTrack.get());
   // ReadMetadata is called *before* checking IsWaitingMediaResources.
-  if (IsWaitingMediaResources()) {
+  if (waiting) {
     return NS_OK;
   }
+  mEssentialTrackBuffers.Clear();
   if (!mAudioTrack && !mVideoTrack) {
     MSE_DEBUG("MediaSourceReader(%p)::ReadMetadata missing track: mAudioTrack=%p mVideoTrack=%p",
               this, mAudioTrack.get(), mVideoTrack.get());

content/media/mediasource/MediaSourceReader.h

@@ -40,6 +40,10 @@ public:
     return NS_OK;
   }
 
+  // Indicates the point in time at which the reader should consider
+  // registered TrackBuffers essential for initialization.
+  void PrepareInitialization();
+
   bool IsWaitingMediaResources() MOZ_OVERRIDE;
 
   void RequestAudioData() MOZ_OVERRIDE;
@@ -105,6 +109,7 @@ private:
   nsRefPtr<MediaDecoderReader> mVideoReader;
 
   nsTArray<nsRefPtr<TrackBuffer>> mTrackBuffers;
+  nsTArray<nsRefPtr<TrackBuffer>> mEssentialTrackBuffers;
   nsRefPtr<TrackBuffer> mAudioTrack;
   nsRefPtr<TrackBuffer> mVideoTrack;
 
@@ -125,6 +130,8 @@ private:
   // after a seek.
   bool mAudioIsSeeking;
   bool mVideoIsSeeking;
+
+  bool mHasEssentialTrackBuffers;
 };
 
 } // namespace mozilla

content/media/mediasource/SourceBuffer.cpp

@@ -564,6 +564,7 @@ SourceBuffer::AppendData(const uint8_t* aData, uint32_t aLength, ErrorResult& aR
   // TODO: Run buffer append algorithm asynchronously (would call StopUpdating()).
   if (mParser->IsInitSegmentPresent(aData, aLength)) {
     MSE_DEBUG("SourceBuffer(%p)::AppendData: New initialization segment.", this);
+    mMediaSource->QueueInitializationEvent();
     mTrackBuffer->DiscardDecoder();
     if (!mTrackBuffer->NewDecoder()) {
       aRv.Throw(NS_ERROR_FAILURE); // XXX: Review error handling.