[MPlayer-users] seeking explanation of -1 and -2 in -vop scale

[Stefan Baehre]

SMuelas wrote:

> > a 720x576 vob, 16:9 aspect, cropped with 710:434:4:74, and then to be 
> > scaled with w=640 and y to well.... be right!
> > 
> Do not crop to w=710. Try to find a multiple of 16, or, at least, 8.

Why? It's important for the codec, but it shouldn't be for the
scaler. Or am I wrong here? Anyway, the output of the scaler should
be multiple of 16, but that's the case with 640.