Hi all Here's the problem: When you have two adjacent frames and the latter is exactly equal to the former, you usually do not need to blit the frame (it's already there). Althrough this works perfectly for video-out display devices (x11,sdl,etc..), it fails for disk-writer devices (such as yuv4mpeg). What happens in this case is second frame is not outputted to disk - and you'll get A/V desync for sure. I have a small video here that demonstrates that, if anyone's interested. So, I wrote a small patch which implements a new control event (which I call VOCTRL_DUPLICATE_FRAME), that is issued to the video out device when there is a frame change and no blitting was done/needed. The VO device then outputs again the last outputted frame (please check this part of the code in vo_yuv4mpeg.c, I'm not sure it's well written). Please CC me on reply, I'm not on the mailing list. Álvaro Lopes