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

[Alain Barthélemy]

Thanks it helps and sorry it was my day of stupid questions.

Le Tuesday 03 August 2004, 16:45:55 ou environ rcooley <rcooley at spamcop.net> a écrit:
> 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.

Thanks. I read once the command line in a mail and did not see it started with
mplayer and not with mencoder. But of course I could read the crop suggestions
with mencoder. Of course I should have guessed it was 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.

I think I read somewhere "autoaspect" gave problems.

> 
> 
> > 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"
>

Thanks but "scale=-1:-2,scale=576:352" was not indicated clearly in the
manual. Did you mean "scale=-1" or "scale=-2" or must I understand scale="take the
original width size":"calculate height using according width and the prescaled
aspect ratio","why a second scale option?".

Stupid question again: do you have so multiples of 16? 

-- 
Alain Barthélemy
cassandre at bartydeux.be
http://bartydeux.be
Linux User #315631