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

[Alain Barthélemy]

Le mercredi 04 août 2004, 02:41:53 ou environ rcooley <rcooley at spamcop.net> a écrit:
> On Wed, 4 Aug 2004 11:11:45 +0200
> Alain Barthélemy <cassandre at bartydeux.be> wrote:
> 
> > Thus why not only "scale=-1:-2". 
> 
> Well, that will give you a video that is 1020 wide, which doesn't seem
> to be what you want.
> 
> Please disregard my advice.  It seems I misunderstood your
> original question.  I hope I didn't cause much confusion.
> 
> However, now that I think I understand, I can offer an answer.
> 
> If you can't use autoaspect, you could use scale to calculate everything
> for you.  Run MPlayer with "crop=718:432:2:72,scale=576:-2".  Then,
> exit mplayer, and look at the output.  It will tell you what dimention
> it scaled the height to to match up with 576, you just have to round it
> up or down to the nearest number that is a multiple of 16. 
> 
> So if mplayer says the video output from that command is 576x242, you
> would then change scale to "scale=576:240", and then pass crop
> dimentions and your new scale dimentions to mencoder.  That should be
> all it takes.
> 
> 
> I'll leave it at that to keep it simple, and prevent confusion.  If you
> are interested in a way to make this process more automatic, feel free
> to ask.
> 

Thanks for all your help. My pictures are now perfectly scaled with

1) mplayer dvd://1 -vf cropdetect
2) -> crop xxx.xxx.xxx.xxx
3) mplayer dvd://1 -vf crop=xxx.xxx.xxx.xxx,scale=576:-2
4) I have now the right measures (with multiples of 16 of course for scaling).

If you ask why a width of 576 and not more, that's because my stand-alone video
reader does not accept width greater than 640 but with a width of 640, I have a
lot of "dropped frames" while mencoding.

Question: when you say there is a way to make the process more automatic, what
do you mean? I use now a simple bash script where I change manually the
values. I goes fast. Of course I made once a simple Perl/Tk GUI with Buttons,
ListBox, etc.

@+

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