[XviD-devel] Display Aspect Ratio -> Pixel Aspect ratio solution

Dirk Knop dknop at stud.uni-goettingen.de
Sat Dec 13 13:32:25 CET 2003

Hi again,

Christoph Lampert schrieb:

>Why exactly do you consider this an "abuse"?  I thought that was what PAR
>is for. 
I've done this with a "Display aspect ratio" dropdown listbox now.
Default is "1:1 (Default)", other options are "4:3 (Anamorph)" and "16:9
(Anamorph)". This now gets used to calculate the appropiate pixel aspect
ratio. If this gets accepted by the windows users we can add propietary
DARs - and maybe even PARs (which will lead to much confusion - as it
did amongst us as well I think...).

>I guess it's very often that users who decode and user who encode aren't
>the same users (What??? How could this happen?), and people playing with
>broken decoders will of course complain.
Yupp. That's a problem i see as well, and why I write now. Now that I
have that stuff working properly (thanks to Edouard and Radek), we need
to adopt the DShow filter to read those par, par_width and par_height
values (or better: let the decoder in core do that) and set the
according output size (again I think it's more suitable in core).
What do you think about this?

>And of course most users don't know what AspectRatio is, even less the 
>difference between PAR and DAR. 
I vote for not letting the user set PAR from VfW. DAR is nearly too much
already, but then there are some people shouting out for anamorph encoding.

>Both could be GUI option. Arbitrary values, hm, better hide that very very
I really would hate to see that as users will find it, no matter how
well you hide things ;)

Ok, bottom line: can we add the proper scaling to the core decoder? If
it would immediatly report the scaled size we wouldn't have to fight
with problems amongst windows users - i.e. my sample doesn't play
correctly (here: scaled) with all dshow based players. Don't know what
this would imply on the *NIX/linux side though.


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