[MPlayer-dev-eng] autoexpand patch

[D Richard Felker III]

On Thu, Nov 18, 2004 at 08:59:59AM +0100, jan gregor wrote:
> > >>That's normal behavior. the 720:576 DVD contains an aspect
> > >>ratio (here 16/9, hence 1024:576) at which the DVD must be
> > >>played.  Unfortunately, when you expand the image with
> > >>-vf expand, the image is first expanded, and *then* the
> > >>final display aspect ratio is computed.
> > >>
> > >>So for a 720:576 image at 16:9, that's 1024:576 final, and the
> > >>width will be expanded by (1024/720) ~= 1.42 You pad the
> > >>image with black by asking for 1024 at 4:3, so the image is padded
> > >>to 1024:767 (rounding error ?), and *then* the width is multiplied
> > >>by ~1.42, and so display at 1456:767
> > >
> > >In other words, it's not a bug, it's a feature? :(
> > 
> > I'd say, it's an implementation side-effect. Aspect-ratio resizing
> > is handled by telling the vo what is required, so it can be done in
> > hardware, while the various video filter are called before that.
> > Unless vf expand has access to the movie aspect ratio, no way
> > this can be done, IMHO.
> 
> I think, this is out of scope of all video filters. Instead of rewriting
> video filters, wouldn't it be better to create an option to ignore
> builtin aspect ratio in movies? Just an idea.

no, this would be horrible. you misunderstand the problem totally...
if you ever ignore the aspect, the output will come out looking
horribly wrong.

rich