| // Copyright 2015 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 COBALT_MEDIA_BASE_VIDEO_RENDERER_SINK_H_ |
| #define COBALT_MEDIA_BASE_VIDEO_RENDERER_SINK_H_ |
| |
| #include "base/logging.h" |
| #include "base/memory/ref_counted.h" |
| #include "base/time.h" |
| #include "cobalt/media/base/media_export.h" |
| #include "cobalt/media/base/video_frame.h" |
| |
| namespace cobalt { |
| namespace media { |
| |
| // VideoRendererSink is an interface representing the end-point for rendered |
| // video frames. An implementation is expected to periodically call Render() on |
| // a callback object. |
| class MEDIA_EXPORT VideoRendererSink { |
| public: |
| class RenderCallback { |
| public: |
| // Returns a VideoFrame for rendering which should be displayed within the |
| // presentation interval [|deadline_min|, |deadline_max|]. Returns NULL if |
| // no frame or no new frame (since the last Render() call) is available for |
| // rendering within the requested interval. Intervals are expected to be |
| // regular, contiguous, and monotonically increasing. Irregular intervals |
| // may affect the rendering decisions made by the underlying callback. |
| // |
| // If |background_rendering| is true, the VideoRenderSink is pumping |
| // callbacks at a lower frequency than normal and the results of the |
| // Render() call may not be used. |
| virtual scoped_refptr<VideoFrame> Render(base::TimeTicks deadline_min, |
| base::TimeTicks deadline_max, |
| bool background_rendering) = 0; |
| |
| // Called by the sink when a VideoFrame previously returned via Render() was |
| // not actually rendered. Must be called before the next Render() call. |
| virtual void OnFrameDropped() = 0; |
| |
| virtual ~RenderCallback() {} |
| }; |
| |
| // Starts video rendering. See RenderCallback for more details. Must be |
| // called to receive Render() callbacks. Callbacks may start immediately, so |
| // |callback| must be ready to receive callbacks before calling Start(). |
| virtual void Start(RenderCallback* callback) = 0; |
| |
| // Stops video rendering, waits for any outstanding calls to the |callback| |
| // given to Start() to complete before returning. No new calls to |callback| |
| // will be issued after this method returns. May be used as a means of power |
| // conservation by the sink implementation, so clients should call this |
| // liberally if no new frames are expected. |
| virtual void Stop() = 0; |
| |
| // Instead of using a callback driven rendering path, allow clients to paint a |
| // single frame as they see fit without regard for the compositor; this is |
| // useful for painting poster images or hole frames without having to issue a |
| // Start() -> Render() -> Stop(). Clients are free to mix usage of Render() |
| // based painting and PaintSingleFrame(). |
| virtual void PaintSingleFrame(const scoped_refptr<VideoFrame>& frame, |
| bool repaint_duplicate_frame = false) = 0; |
| |
| virtual ~VideoRendererSink() {} |
| }; |
| |
| } // namespace media |
| } // namespace cobalt |
| |
| #endif // COBALT_MEDIA_BASE_VIDEO_RENDERER_SINK_H_ |