[MPlayer-users] DVD rip Crop & scale little problems

[rcooley]

On Tue, 3 Aug 2004 18:17:32 +0200
Alain Barthélemy <cassandre at bartydeux.be> wrote:

> but mencoder -vf cropdetect 

mencoder doesn't do -vf cropdetect, only mplayer.

> gives me a cropping dimension of 718x432 (1.66:1 not 1.77:1). 

Which is why the lavcopt "autoaspect" exists, to calulate the new aspect
you need to use after cropping.


> If I rescale, respecting the dimensions, to a width of 576, I get a
> scaling of 576x352. If I read now the movie on a standalone reader, I
> have a vertically distorted image and I have to force the reader to
> read the movie with a 16:9 aspect.

Of course, because you scaled the video without taking the source aspect
into consideration.

> I don't have that distorsion problem if I use:  mencoder -aspect=16:9
> ... -vf hqdn3d=3:2:5,crop=718:432:2:72,scale=576:-2 ...  

Because scale "-2" takes aspect into consideration for you.

> Thus how can I calculate manually the cropping and rescaling of the
> image? 

Instead of doing it manually, I would suggest letting scale do it
automatically. eg:  "-vf crop=718:432:2:72,scale=-1:-2,scale=576:352"