Bug 879669 - Part 3: Start recording when tracks have been added. r=roc

content/media/MediaRecorder.cpp

@@ -17,12 +17,16 @@
 #include "nsIDOMFile.h"
 #include "mozilla/dom/BlobEvent.h"
 
+
+#include "mozilla/dom/AudioStreamTrack.h"
+#include "mozilla/dom/VideoStreamTrack.h"
+
 namespace mozilla {
 
 namespace dom {
 
-NS_IMPL_CYCLE_COLLECTION_INHERITED_1(MediaRecorder, nsDOMEventTargetHelper,
-                                     mStream)
+NS_IMPL_CYCLE_COLLECTION_INHERITED_2(MediaRecorder, nsDOMEventTargetHelper,
+                                     mStream, mSession)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(MediaRecorder)
 NS_INTERFACE_MAP_END_INHERITING(nsDOMEventTargetHelper)
@@ -45,7 +49,7 @@ NS_IMPL_RELEASE_INHERITED(MediaRecorder, nsDOMEventTargetHelper)
  *
  * Life cycle of a Session object.
  * 1) Initialization Stage (in main thread)
- *    Setup media streams in MSG, and bind MediaEncoder with Source Stream.
+ *    Setup media streams in MSG, and bind MediaEncoder with Source Stream when mStream is available.
  *    Resource allocation, such as encoded data cache buffer and MediaEncoder.
  *    Create read thread.
  *    Automatically switch to Extract stage in the end of this stage.
@@ -90,7 +94,7 @@ class MediaRecorder::Session: public nsIObserver
     }
 
   private:
-    Session *mSession;
+    nsRefPtr<Session> mSession;
   };
 
   // Record thread task.
@@ -110,7 +114,36 @@ class MediaRecorder::Session: public nsIObserver
     }
 
   private:
-    Session *mSession;
+    nsRefPtr<Session> mSession;
+  };
+
+  // For Ensure recorder has tracks to record.
+  class TracksAvailableCallback : public DOMMediaStream::OnTracksAvailableCallback
+  {
+  public:
+    TracksAvailableCallback(Session *aSession)
+     : mSession(aSession) {}
+    virtual void NotifyTracksAvailable(DOMMediaStream* aStream)
+    {
+      uint8_t trackType = aStream->GetHintContents();
+      // ToDo: GetHintContents return 0 when recording media tags.
+      if (trackType == 0) {
+        nsTArray<nsRefPtr<mozilla::dom::AudioStreamTrack> > audioTracks;
+        aStream->GetAudioTracks(audioTracks);
+        nsTArray<nsRefPtr<mozilla::dom::VideoStreamTrack> > videoTracks;
+        aStream->GetVideoTracks(videoTracks);
+        // What is inside the track
+        if (videoTracks.Length() > 0) {
+          trackType |= DOMMediaStream::HINT_CONTENTS_VIDEO;
+        }
+        if (audioTracks.Length() > 0) {
+          trackType |= DOMMediaStream::HINT_CONTENTS_AUDIO;
+        }
+      }
+      mSession->AfterTracksAdded(trackType);
+    }
+  private:
+    nsRefPtr<Session> mSession;
   };
 
   // Main thread task.
@@ -154,6 +187,7 @@ class MediaRecorder::Session: public nsIObserver
   friend class PushBlobRunnable;
   friend class ExtractRunnable;
   friend class DestroyRunnable;
+  friend class TracksAvailableCallback;
 
 public:
   Session(MediaRecorder* aRecorder, int32_t aTimeSlice)
@@ -169,8 +203,6 @@ public:
   // Only DestroyRunnable is allowed to delete Session object.
   virtual ~Session()
   {
-    MOZ_ASSERT(NS_IsMainThread());
-
     CleanupStreams();
   }
 
@@ -179,22 +211,6 @@ public:
     MOZ_ASSERT(NS_IsMainThread());
 
     SetupStreams();
-
-    // Create a thread to read encode media data from MediaEncoder.
-    if (!mReadThread) {
-      nsresult rv = NS_NewNamedThread("Media Encoder", getter_AddRefs(mReadThread));
-      if (NS_FAILED(rv)) {
-        CleanupStreams();
-        mRecorder->NotifyError(rv);
-        return;
-      }
-    }
-
-    // In case source media stream does not notify track end, recieve
-    // shutdown notification and stop Read Thread.
-    nsContentUtils::RegisterShutdownObserver(this);
-
-    mReadThread->Dispatch(new ExtractRunnable(this), NS_DISPATCH_NORMAL);
   }
 
   void Stop()
@@ -290,14 +306,57 @@ private:
     mInputPort = mTrackUnionStream->AllocateInputPort(mRecorder->mStream->GetStream(), MediaInputPort::FLAG_BLOCK_OUTPUT);
 
     // Allocate encoder and bind with the Track Union Stream.
-    mEncoder = MediaEncoder::CreateEncoder(NS_LITERAL_STRING(""));
-    MOZ_ASSERT(mEncoder, "CreateEncoder failed");
-
-    if (mEncoder) {
-      mTrackUnionStream->AddListener(mEncoder);
-    }
+    TracksAvailableCallback* tracksAvailableCallback = new TracksAvailableCallback(mRecorder->mSession);
+    mRecorder->mStream->OnTracksAvailable(tracksAvailableCallback);
   }
 
+  void AfterTracksAdded(uint8_t aTrackTypes)
+  {
+    MOZ_ASSERT(NS_IsMainThread());
+
+    // Allocate encoder and bind with union stream.
+    // At this stage, the API doesn't allow UA to choose the output mimeType format.
+    mEncoder = MediaEncoder::CreateEncoder(NS_LITERAL_STRING(""), aTrackTypes);
+
+    if (!mEncoder) {
+      DoSessionEndTask(NS_ERROR_ABORT);
+      return;
+    }
+
+    // media stream is ready but has been issued stop command
+    if (mRecorder->mState == RecordingState::Inactive) {
+      DoSessionEndTask(NS_OK);
+      return;
+    }
+    mTrackUnionStream->AddListener(mEncoder);
+    // Create a thread to read encode media data from MediaEncoder.
+    if (!mReadThread) {
+      nsresult rv = NS_NewNamedThread("Media Encoder", getter_AddRefs(mReadThread));
+      if (NS_FAILED(rv)) {
+        DoSessionEndTask(rv);
+        return;
+      }
+    }
+
+    // In case source media stream does not notify track end, recieve
+    // shutdown notification and stop Read Thread.
+    nsContentUtils::RegisterShutdownObserver(this);
+
+    mReadThread->Dispatch(new ExtractRunnable(this), NS_DISPATCH_NORMAL);
+  }
+  // application should get blob and onstop event
+  void DoSessionEndTask(nsresult rv)
+  {
+    MOZ_ASSERT(NS_IsMainThread());
+
+    if (NS_FAILED(rv)) {
+      mRecorder->NotifyError(rv);
+    }
+    CleanupStreams();
+    // Destroy this session object in main thread.
+    NS_DispatchToMainThread(new PushBlobRunnable(this));
+    NS_DispatchToMainThread(new DestroyRunnable(already_AddRefed<Session>(this)));
+  }
   void CleanupStreams()
   {
     if (mInputPort.get()) {
@@ -430,11 +489,10 @@ MediaRecorder::Stop(ErrorResult& aResult)
     aResult.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
     return;
   }
+  mState = RecordingState::Inactive;
 
   mSession->Stop();
   mSession = nullptr;
-
-  mState = RecordingState::Inactive;
 }
 
 void

content/media/MediaRecorder.h

@@ -104,7 +104,7 @@ protected:
   // The current state of the MediaRecorder object.
   RecordingState mState;
   // Current recording session.
-  Session *mSession;
+  nsRefPtr<Session> mSession;
   // Thread safe for mMimeType.
   Mutex mMutex;
   // It specifies the container format as well as the audio and video capture formats.