When playing youtube html5 movies in google chrome, or moving the cursor over youtube flash movies, the display driver sometimes send to the spice server bitmaps that contain video frames, but are bigger than the previous frames sent.
The bigger frames are not synchronized with the video stream, and their display time is independent of the display time of other frames. This appear to the user as glitches in the movie.
Attach such big bitmaps to the video stream they contain.
Video playbacks that once suffered from glitches due to the above cause, should now be smooth, when the spice client runs with >= spice-gtk-0.11-9.el6