[MPlayer-dev-eng] Re: aspect ratio: container vs vd_ffmpeg

ChristianHJW christian at matroska.org
Wed May 7 09:20:27 CEST 2003

Balatoni Denes wrote:
> Hi!
> > just a note that rm have displaysize too in the container - some additional 
> motiviation.
> bye Denes

matroska has both PAR ( Pixel Aspect Ratio ) and DAR ( Display Aspect 
Ratio ) fields, but dont ask me which one overrides which, i recently 
lost overview of how it was actually implemented :D .

Leaves me to mention that during the muxing process we decided to read 
the AR flag in the MPEG4 codec header and set it in the matroska track 
header accordingly, but only if no other value is set there.

The idea is to simply copy the AR flag from the codec, but if the user 
would decide to use a different AR for playback ( e.g. if he messed up 
with calculating the correct resizing ) he will be able to change the 
actual output ratio to a better number.



P.S. We also decided that we will have to do something to stop Mosu. He 
cant work a lot on matroska currently, but even then he is progressing 
so quickly that the 4 - 5 Windows devs we have cant not implement things 
as quickly as he does, so meanwhile his Linux tools are in much better 
shape than the win32 stuff we have :D !! /me is eagerly waiting for 
encoding support in mencoder and a transmuxer converting AVI streams 
into 'native' matroska MPEG4 video streams without 'dummy frames' ....

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