Make painting a single frame a permanent API on VideoRendererSink.

media/renderers/video_renderer_impl.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_RENDERERS_VIDEO_RENDERER_IMPL_H_
 #define MEDIA_RENDERERS_VIDEO_RENDERER_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 77 matching lines @@
  private:
   // Callback for |video_frame_stream_| initialization.
   void OnVideoFrameStreamInitialized(bool success);
 
   // Functions to notify certain events to the RendererClient.
   void OnPlaybackError(PipelineStatus error);
   void OnPlaybackEnded();
   void OnStatisticsUpdate(const PipelineStatistics& stats);
   void OnBufferingStateChange(BufferingState state);
   void OnWaitingForDecryptionKey();
-  void OnVideoNaturalSizeChange(const gfx::Size& size);
-  void OnVideoOpacityChange(bool opaque);
 
   // Callback for |video_frame_stream_| to deliver decoded video frames and
   // report video decoding status. If a frame is available the planes will be
   // copied asynchronously and FrameReady will be called once finished copying.
   void FrameReadyForCopyingToGpuMemoryBuffers(
       VideoFrameStream::Status status,
       const scoped_refptr<VideoFrame>& frame);
 
   // Callback for |video_frame_stream_| to deliver decoded video frames and
   // report video decoding status.
   void FrameReady(uint32_t sequence_token,
                   VideoFrameStream::Status status,
                   const scoped_refptr<VideoFrame>& frame);
 
   // Helper method for enqueueing a frame to |alogorithm_|.
   void AddReadyFrame_Locked(const scoped_refptr<VideoFrame>& frame);
 
   // Helper method that schedules an asynchronous read from the
   // |video_frame_stream_| as long as there isn't a pending read and we have
   // capacity.
-  void AttemptRead();
   void AttemptRead_Locked();
 
   // Called when VideoFrameStream::Reset() completes.
   void OnVideoFrameStreamResetDone();
 
   // Returns true if the renderer has enough data for playback purposes.
   // Note that having enough data may be due to reaching end of stream.
   bool HaveEnoughData_Locked();
   void TransitionToHaveEnough_Locked();
   void TransitionToHaveNothing();
 
   // Runs |statistics_cb_| with |frames_decoded_| and |frames_dropped_|, resets
   // them to 0.
   void UpdateStats_Locked();
 
-  // Called after we've painted the first frame.  If |time_progressing_| is
-  // false it Stop() on |sink_|.
-  void MaybeStopSinkAfterFirstPaint();
-
   // Returns true if there is no more room for additional buffered frames.
   bool HaveReachedBufferingCap();
 
   // Starts or stops |sink_| respectively. Do not call while |lock_| is held.
   void StartSink();
   void StopSink();
 
   // Fires |ended_cb_| if there are no remaining usable frames and
   // |received_end_of_stream_| is true.  Sets |rendered_end_of_stream_| if it
   // does so.
   //
   // When called from the media thread, |time_progressing| should reflect the
   // value of |time_progressing_|.  When called from Render() on the sink
-  // callback thread, the inverse of |render_first_frame_and_stop_| should be
-  // used as a proxy for |time_progressing_|.
+  // callback thread, |time_progressing| must be true since Render() could not
+  // have been called otherwise.
   void MaybeFireEndedCallback_Locked(bool time_progressing);
 
   // Helper method for converting a single media timestamp to wall clock time.
   base::TimeTicks ConvertMediaTimestamp(base::TimeDelta media_timestamp);
 
   base::TimeTicks GetCurrentMediaTimeAsWallClockTime();
 
   // Helper method for checking if a frame timestamp plus the frame's expected
   // duration is before |start_timestamp_|.
   bool IsBeforeStartTime(base::TimeDelta timestamp);
 
   // Attempts to remove frames which are no longer effective for rendering when
   // |buffering_state_| == BUFFERING_HAVE_NOTHING or |was_background_rendering_|
   // is true.  If the current media time as provided by |wall_clock_time_cb_| is
   // null, no frame expiration will be done.
   //
   // When background rendering the method will expire all frames before the
   // current wall clock time since it's expected that there will be long delays
   // between each Render() call in this state.
   //
   // When in the underflow state the method will first attempt to remove expired
   // frames before the current media time plus duration. If |sink_started_| is
   // true, nothing more can be done. However, if false, and there are still no
   // effective frames in the queue, the entire frame queue will be released to
   // avoid any stalling.
   void RemoveFramesForUnderflowOrBackgroundRendering();
 
+  // Notifies |client_| in the event of frame size or opacity changes. Must be
+  // called on |task_runner_|.
+  void CheckForMetadataChanges(VideoPixelFormat pixel_format,
+                               const gfx::Size& natural_size);
+
+  // Both calls AttemptRead_Locked() and CheckForMetadataChanges(). Must be
+  // called on |task_runner_|.
+  void AttemptReadAndCheckForMetadataChanges(VideoPixelFormat pixel_format,
+                                             const gfx::Size& natural_size);
+
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   // Sink which calls into VideoRendererImpl via Render() for video frames.  Do
   // not call any methods on the sink while |lock_| is held or the two threads
   // might deadlock. Do not call Start() or Stop() on the sink directly, use
   // StartSink() and StopSink() to ensure background rendering is started.  Only
   // access these values on |task_runner_|.
   VideoRendererSink* const sink_;
   bool sink_started_;
 
@@ skipping 78 matching lines @@
 
   // Indicates that Render() was called with |background_rendering| set to true,
   // so we've entered a background rendering mode where dropped frames are not
   // counted.  Must be accessed under |lock_| once |sink_| is started.
   bool was_background_rendering_;
 
   // Indicates whether or not media time is currently progressing or not.  Must
   // only be accessed from |task_runner_|.
   bool time_progressing_;
 
-  // Indicates that Render() should only render the first frame and then request
-  // that the sink be stopped.  |posted_maybe_stop_after_first_paint_| is used
-  // to avoid repeated task posts.
-  bool render_first_frame_and_stop_;
-  bool posted_maybe_stop_after_first_paint_;
-
   // Memory usage of |algorithm_| recorded during the last UpdateStats_Locked()
   // call.
   int64_t last_video_memory_usage_;
 
-  // Indicates if Render() has been called yet.
+  // Indicates if a frame has been processed by CheckForMetadataChanges().
   bool have_renderered_frames_;
+
   // Tracks last frame properties to detect and notify client of any changes.
   gfx::Size last_frame_natural_size_;
   bool last_frame_opaque_;
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<VideoRendererImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoRendererImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_RENDERERS_VIDEO_RENDERER_IMPL_H_