[MPlayer-dev-eng] Recommend error for bad dimensions

D Richard Felker III dalias at aerifal.cx
Tue Mar 2 21:37:38 CET 2004

On Tue, Mar 02, 2004 at 05:28:05PM +0000, Adam Rice wrote:
> Quoting D Richard Felker III (dalias at aerifal.cx):
> > Would anyone object if I modify ve_lavc's config to FAIL by default if
> > dimensions are not multiples of 16? There would be an option to
> > override ("forcebadsize" maybe?) but IMO too many newbies refuse to
> > RTFM and generate poor encodes (which some players won't even play) by
> > choosing bad dimensions.
> Erm... the docs recommend to use cropdetect, and cropdetect helpfully prints
> out a commandline fragment with the exact dimensions of the video. If mencoder
> then choked on the commandline it just suggested, it wouldn't exactly inspire
> confidence, now, would it? Besides, it seems a little absurd to require users
> to do mental arithmetic when they're sat in front of a $1000 adding machine.
> I propose that the problem lies not in lavc, but in cropdetect. I think
> cropdetect should be modified to report the exact dimensions of the useful
> video, but suggest dimensions that are rounded to multiples of 16 (or perhaps
> multiples of 8 when the video < 400 pixels wide or so).

No, this is completely idiotic. Normally you should SCALE after crop,
in which case any even dimensions are valid for crop. On the other
hand, it should also be an error if you _scale_ to invalid dimensions.
So the logic belongs in ve_lavc, not filters. Especially since the
filters might not even be used for encoding but just for playing!!


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