[XviD-devel] Aspect Ratio

Michael Niedermayer xvid-devel@xvid.org
Thu, 24 Oct 2002 13:03:21 +0200


Hi

On Thursday 24 October 2002 12:35, peter ross wrote:
[...]
> on a related note,
> some of the general flags are vol-based (quant_type, interlacing,
> quarterpel, and aspectratio). currently xvid will write/force a vol
> if quant_type, or the quantizer tables differ between two frames.
> however the other stuff is assumed to be constant thoughough the video
> sequence.
>
> we need to decide whether to,
> * support encoding of vol-based stuff across frames; or,
> * permit the vol-based options to be specified only at codec startup.
>
> i'd like to see xvid do as-much-as-possible on a per-frame basis.
u should check if the mpeg4 std allows the VOL stuff to be changed between 
frames, iam not sure, AFAIK it is not even allowed to have more than 1 VOL 
header per stream (the momusys reference does complain if there is more then 
1 VOL header) allthough all AVI based codecs add the VOL to each keyframe ...

>
> >P.S. This is another feature which no other codec has ;-> great for
> >homepage announcements...
>
> yipeee.
> petes awaiting the "xvid+obmc" annoucement... it's gonna be great,
> given that no other codec OR _profile_ supports it... !
and that means its not part of mpeg4 -> there will be no interoperability with 
any mpeg4 compliant codec anymore 

[...]

Michael