> So it's ffdshow/libvacodec which forgets the rounding. Apart from > that, it seems to decode fine - no other artifacts. Hi, I just downloaded ffdshow sources and here it is, at the very beginning of mpeg_motion() if(s->quarter_sample) { motion_x>>=1; motion_y>>=1; } Which is wrong. I don't even know where to post this bug report, so I write it here ;) Radek