[MPlayer-users] set aspect ratio code? or resize?

[Joonas Koivunen]

On Sunday 18 April 2004 16:22, Mikhail Ramendik wrote:
> Hello,
>
> My source material is 720x576 PAL. I want to create DivX AVIs for
> playing on computers (with all players inckuding Windoze). As I
> understand, to play back correctly, the films need to be recoded into a
> 4:3 aspect ratio (aka 1.33:1, from 1.25:1).
Aspect ratio itself doesnt have anything to do with you being able to play it 
under Windows/other players or not. 

I guess you are on the right tracks; libavcodec can encode in the original 
aspect ratio and store it in the video, only mplayer reads this information 
and prescales accordingly. Other players just play it unscaled -- as in wrong 
aspect ratio. As long as you don't use -lavcopts aspect=X option, you'll be 
safe.

> To have maximum quality *and* compatibility, should I set the aspect
> ratio code in the AVI, or should I resize when encoding?
AFAIK AVI doesn't have this aspect ratio code, it can only be stored in the 
video headers (not avi). You should resize when you encode (like all movie 
groups do for example, as their rules only support xvid and divx codecs).

> And if I should set the aspect ratio code: is it possible to just add
> the code to an AVI *without* re-encoding? i.e. mencoder -ovc copy -oac
> copy (and some options to add the aspect ratio code).
This was discussed/asked a long time ago I think, cannot remember any 
solutions..

> Thanks!
BTW I probably get flamed for wrong info but this is just what I've learned, 
through trial and error :)

> Yours, Mikhail Ramendik
-rzei