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

Dirk Knop dknop at stud.uni-goettingen.de
Fri Dec 12 14:10:37 CET 2003

Selam everybody,

(hm, new codename for beta3? ;) )
I was looking into aspect ratio addition to VfW GUI and started with a 
small hack - setting frame.par to the #defines in xvid.h. Unfortunately 
this isn't really what (windows-)users expect when they choose an aspect 
So I want to make it Display Aspect Ratio in the GUI and abuse the 
par_height and par_width for that. (I.e. encoder gets fed with a 640x240 
image and a 4:3 DAR - set par_height to 2 and par_width to 1.). This 
would work with mplayer (verified). Hardware players should work with 
that, too. Only some windows players/decoders would have problems with 
such anamorphic encodes due to the rescaling necessary after building a 
directshow filter graph.
On the other hand, people who want anamorphic encoding are capable of 
using a correct player/decoder. Other users won't be affected since the 
default will be 1:1 PAR/DAR.

Is that too much of a "hack" of the standard or can we agree on such an 
abuse of the PAR?


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