[AG-TECH] H263

Ivan R. Judson judson at mcs.anl.gov
Tue Jan 27 16:21:53 CST 2004


I just confirmed that our existing ag-vic code does not crash in the
presence of the OM h.263 streams. It was an incorrect condition in how
ag-vic was determining the H.263 frame size (the custom flag was wrong in
ag-vic). I've entirely removed H.263 codecs from ag-vic, so ag-vic now just
drops these packets like any other codec it doesn't recognize.

It's not great, but it's better than crashing :-)


PS -- This will be in the next version of the AGTk in the spring release. 

> -----Original Message-----
> From: owner-ag-tech at mcs.anl.gov 
> [mailto:owner-ag-tech at mcs.anl.gov] On Behalf Of Andrew Swan
> Sent: Thursday, January 22, 2004 1:07 AM
> To: Gurcharan S. Khanna
> Cc: jeremy at biochem.uthscsa.edu; ag-tech at mcs.anl.gov
> Subject: Re: [AG-TECH] H263
> Gurcharan S. Khanna wrote:
> > can you even do 640x480 with non-omvic? i thought i tried some time 
> > ago and never got that to work for some reason.
> as long as you use h.261, all you can do is 352x288 or 
> 176x144 (also called cif or qcif).  this isn't a shortcoming 
> of vic, it is part of the h.261 standard.  the bitstream 
> syntax simply doesn't have a way to specify arbitrary frame 
> resolution, all it has is a single bit to select cif or qcif.
> there are various patches floating around to implement h.263 
> in uclvic which could probably be applied to agvic without 
> too much trouble but as far as i know, omvic is the only one 
> being actively worked on...
> -Andrew

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