diff options
Diffstat (limited to 'media/capture/video/video_capture_device.h')
| -rw-r--r-- | media/capture/video/video_capture_device.h | 42 |
1 files changed, 35 insertions, 7 deletions
diff --git a/media/capture/video/video_capture_device.h b/media/capture/video/video_capture_device.h index 7d8ac1f..71a4f3e 100644 --- a/media/capture/video/video_capture_device.h +++ b/media/capture/video/video_capture_device.h @@ -242,6 +242,16 @@ class MEDIA_EXPORT VideoCaptureDevice { const scoped_refptr<VideoFrame>& frame, const base::TimeTicks& timestamp) = 0; + // Attempts to reserve the same Buffer provided in the last call to one of + // the OnIncomingCapturedXXX() methods. This will fail if the content of the + // Buffer has not been preserved, or if the |dimensions|, |format|, or + // |storage| disagree with how it was reserved via ReserveOutputBuffer(). + // When this operation fails, nullptr will be returned. + virtual scoped_ptr<Buffer> ResurrectLastOutputBuffer( + const gfx::Size& dimensions, + VideoPixelFormat format, + VideoPixelStorage storage) = 0; + // An error has occurred that cannot be handled and VideoCaptureDevice must // be StopAndDeAllocate()-ed. |reason| is a text description of the error. virtual void OnError(const tracked_objects::Location& from_here, @@ -257,18 +267,36 @@ class MEDIA_EXPORT VideoCaptureDevice { virtual ~VideoCaptureDevice(); - // Prepares the camera for use. After this function has been called no other - // applications can use the camera. StopAndDeAllocate() must be called before - // the object is deleted. + // Prepares the video capturer for use. StopAndDeAllocate() must be called + // before the object is deleted. virtual void AllocateAndStart(const VideoCaptureParams& params, scoped_ptr<Client> client) = 0; - // Deallocates the camera, possibly asynchronously. + // In cases where the video capturer self-pauses (e.g., a screen capturer + // where the screen's content has not changed in a while), consumers may call + // this to request a "refresh frame" be delivered to the Client. This is used + // in a number of circumstances, such as: + // + // 1. An additional consumer of video frames is starting up and requires a + // first frame (as opposed to not receiving a frame for an indeterminate + // amount of time). + // 2. A few repeats of the same frame would allow a lossy video encoder to + // improve the video quality of unchanging content. + // + // The default implementation is a no-op. VideoCaptureDevice implementations + // are not required to honor this request, especially if they do not + // self-pause and/or if honoring the request would cause them to exceed their + // configured maximum frame rate. Any VideoCaptureDevice that does self-pause, + // however, should provide an implementation of this method that makes + // reasonable attempts to honor these requests. + virtual void RequestRefreshFrame() {} + + // Deallocates the video capturer, possibly asynchronously. // // This call requires the device to do the following things, eventually: put - // camera hardware into a state where other applications could use it, free - // the memory associated with capture, and delete the |client| pointer passed - // into AllocateAndStart. + // hardware into a state where other applications could use it, free the + // memory associated with capture, and delete the |client| pointer passed into + // AllocateAndStart. // // If deallocation is done asynchronously, then the device implementation must // ensure that a subsequent AllocateAndStart() operation targeting the same ID |