Re: SFMC codec ???

Jason Williams (streak@ccwf.cc.utexas.edu)
Fri, 7 Aug 1998 18:02:46 -0500 (CDT)


On Wed, 5 Aug 1998, Mark Andrew Nassy wrote:
> i am not familar with rtp (i assume this stands for real time protocol, is
> that correct). if it is not too much to ask would you mind explaining (to a
> non-programmer) how this protocol may affect the quality of the video.

Yeah, it's the Real Time Protocol. I believe RTP has less packet overhead
for headers..but I'm not sure. If so, then it would mean it could
transfer the same amount of data as the CU format with less overhead. But
I'm no expert on it. From what I've seen, CU mainly uses RTP as a means
for H.323 compliant conference. The 3.X client uses RTP for video and
audio (G.723 only I think) for MPCS servers.

> and from an end users (me) point of view (pov) what would better refer to.
> ie, if it were / is possible to use the same settings, codec, hardware, etc
> to connect to a reflector with the cu header protocol then do the same or
> similar thing with rtp when a remote participant views my video what would
> the difference be.

>From the end user's point of view, there is no different that I know of.
It's transparent to the users. The same way you don't have to what type
of gas you put in your car when you drive to work. It doesn't matter as
long as it gets you there.

> would similar changes due to using rtp also apply to audio.

I could be wrong, but it looks like CU only encodes G.723 audio into RTP
for H.323 clients. So unless you're using one of the G.723 codecs for
audio, it won't matter at all.

Also gotta remember that RTP is only supported either in a DC or on MPCS
servers. The majority of the reflectors out there are White Pine 2.1 or
Enhanced Reflectors which don't use RTP at all.

--
streak@ccwf.cc.utexas.edu    * Jason Williams -- Austin, Tx.  |     |
streak@mail.utexas.edu       * University of Texas at Austin  | ___ |
streak@cs.utexas.edu         * BS Computer Science             \_|_/
*************** http://ccwf.cc.utexas.edu/~streak/ **************|