[Ffmpeg-devel] Adding a file type, and VIC codecs

Michael Niedermayer michaelni
Tue Oct 17 20:26:14 CEST 2006


On Tue, Oct 17, 2006 at 11:24:44AM -0400, Derek Piper wrote:
> 	Hi,
> 	I have a question about VIC codecs, and I've not been able to find 
> 	an answer. As I understand it, ffmpeg (libavcodec) and VIC have different 
> implementations of H261 and H263. Is anyone trying / has anyone tried to 
> add the VIC implementations of the codecs to ffmpeg and libavcodec so 
> that it is possible to decode frames from VIC into something ffmpeg can 
> understand and from there convert to another target format?
> 	I am interested in this as I have written an application that 
> 	captures audio and video data from an AccessGrid conference. AccessGrid 
> uses the MBone tools VIC and RAT for videoconferencing. My program is 
> called AGVCR and has been released for nearly a year now and has improved 
> considerably in that time. AGVCR can record almost unlimited video and 
> audio sources from effectively any number of RTP/RTCP connections. One 
> of the features I am interested in adding is being able to convert an 
> AGVCR recorded file (reduced down to only one video and audio source) to 
> an MPEG or similar file for ease of distribution.
> 	In conjunction with the work from another individual, I would like 
> 	to add the AGVCR file specification to libavformat. Is that something that 
> might be possible to do?. At present, that reader works for the files, 
> the only problem is the H261 frames cannot be decoded by the standard 
> H261 decoder that ffmpeg has.
> 	If it were possible (and it's certainly not a small job) to add the 
> 	VIC codecs to libavcodec, would that be something welcomed by the ffmpeg 
> maintainers? I want to ask this before any work starts on it so that if 
> it's not acceptable for certain reasons that I understand this and work 
> on an alternative solution and not waste time on it.
> 	If anyone is interested in learning more about AGVCR, you can simply 
> email me directly off-list. I won't spam this list with adverts for my 
> own program :)
> 	Please let me know what the view is on adding VIC codecs. Obviously 
> they would be differentiated from the ffmpeg versions, e.g. 'vich261', 
> 'vich263'.

what is the difference between vic-h26* and normal h26* ?

we certainly would like to support as many codecs as possible so if you
want to improve our h.263 codec so it can decode oher variants, or if
you want to add support for another h.263 like codec similar to how
msmpeg4* is handled, that all would be welcome

if OTOH you just want to drop some random implemntation into ffmpeg which
then would have alot of code duplicated, then this is completely unacceptable

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is

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