You are right, but only for XviD. If I do YV12 -> YV12 (Helix), VDubMod asks for YUY2, if I do YV12 -> XviD, VDubMod asks for YV12. I will investigate some more. Either something is hard-coded in VDubMod to prefer YV12 for XviD, or my YV12 compressor is somehow not communicating well enough to VDubMod that it would really really like YV12 as input