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Recording H.263 streams

Hi Aurelien and Joao -

Since you both were looking at recording some segments for me to use in
debugging the H.263 codec, I thought you might find the attached
messages useful.

I am very close to being ready to send out an alpha test of the H.263
codec.  I still need to fix the video capture abstractions so that we
can grab full-sized images on Windows. while i'm working on this part of
the code i'm also trying to add support for the WDM model so that we can
support more devices.  i won't spend a lot of time on this if i can't do
it quickly. I am close to having it done, but it will take another day
or two before I can package up a binary alpha release.

I ran some interoperability tests with uclvic 2.8ucl1.1.4.  uclvic will
play the streams produced by omvic, but there is a small visual artifact
when there is rapid motion.  i am pretty sure this is a known problem
with the RTP processing in uclvic -- on B packets they send/recv the
packet but have the wrong starting MB address - i think it is off by
one.  still works though.  Andrew made a good suggestion: why not figure
out the patch to uclvic to fix the problem.  it would need to be in the
file .../codec/h263/h263rtp.c - just look where the RTP header is
created.

omvic can play the h.263 streams from uclvic, but there are numerous
errors.  uclvic sends MV block encoding and i have never been able to
test that in omvic because i don't generate any MV encodings and i
haven't gotten a recorded stream to use for testing yet.  i suspect it
will be relatively easy to fix once someone takes a look at the code. 
there were other problems in the decoder so i suspect lloyd was unable
to figure out which error he was getting.  the current code works on
everything else, so the MV errors will be easy to figure out.

We have done some testing on other platforms, but if you want to try the
code you can do it.  Just check-out the h263_branch from the CVS archive
and build the system.  i'm pretty sure it runs on Linux, it should work
for CIF images on Windows, and probably works on FBSD.  If you do it,
let me know how it goes.
	Larry
p.s. I still want the recorded streams.  I doubt we can interoperate
with the polycom until the RTP payload format is updated to h263-1998,
but that is another reason why I need the recorded streams.
p.p.s. If you try the code at high-quality, you'll see coding artifacts
around sharp edges.  This is due to AC term overflow (i.e., there is not
enough resolution to represent the AC terms near the DC term).  I
implemented the optional modified quantization extension (Annex T).  you
can turn it on by adding the following command line option
	-codec h263:modQ
that will give you pristine images at quantization=1.
-- 
Professor Lawrence A. Rowe          Internet:  Rowe@BMRC.Berkeley.EDU
Computer Science Division - EECS       Phone: 510-642-5117
University of California, Berkeley       Fax: 510-642-5615
Berkeley, CA 94720-1776            URL: http://bmrc.berkeley.edu/~larry

Folks-

Has anyone successfully multicast directly from a
standalone Polycom ViewStation FX, and received the
video/audio with vat or vic? with quicktime? with
IPTV?

I believe this can be done because of the
following FAQ:

Q:How does the FiewStation FX system support streaming?

A:The ViewStation FX system can be used to conduct live webcasts of
meetings or events using streaming audio and video over multicast-enabled
networks supporting Cisco IP TV viewer or Apple Quicktime...

Which can be found at:
http://www.polycom.com/resource_center/1,,pw-810,FF.html

We are thinking of getting one of these to try out.

Any comments on this setup are very much appreciated.

Thanks

-Craig



I have done this with Quicktime.  Haven't tried any of the others.

> -----Original Message-----
> From: Craig M. Votava [mailto:craig@lucent.com] 
> Sent: Thursday, May 22, 2003 10:12 AM
> To: MBONE Mailing List (External)
> Subject: Multicasting from Polycom ViewStation FX?
> 
> 
> Folks-
> 
> Has anyone successfully multicast directly from a
> standalone Polycom ViewStation FX, and received the
> video/audio with vat or vic? with quicktime? with
> IPTV?
> 
> I believe this can be done because of the
> following FAQ:
> 
> Q:How does the FiewStation FX system support streaming?
> 
> A:The ViewStation FX system can be used to conduct live 
> webcasts of meetings or events using streaming audio and 
> video over multicast-enabled networks supporting Cisco IP TV 
> viewer or Apple Quicktime...
> 
> Which can be found at: 
> http://www.polycom.com/resource_center/1,,pw-> 810,FF.html
> 
> We 
> are thinking of getting one of these to try 
> out.
> 
> Any comments on this setup are very much appreciated.
> 
> Thanks
> 
> -Craig
> 
> 



We've recently purchased two of these units and initial testing bears 
out the claims.
Anything that is being viewed at an FX (being a videoconference, direct 
input from the camera or an external source such as a VCR) can be 
multicast.  It is simply an admin function to turn on streaming.

 From the users perspective, they go to the FX web-site and select a 
conference to view.  It implies that more than one conference could be 
multicast at the same time although we haven't tested that.

I've viewed the multicast steam using both the Quicktime and IPTV 
plugins.  The multicast bandwidth is limited to 512Kbps.
It seems to work fine, but it's early days so I am reluctant to pass 
opinions on the quality and reliability.

Craig M. Votava wrote:
> Folks-
> 
> Has anyone successfully multicast directly from a
> standalone Polycom ViewStation FX, and received the
> video/audio with vat or vic? with quicktime? with
> IPTV?
> 
> I believe this can be done because of the
> following FAQ:
> 
> Q:How does the FiewStation FX system support streaming?
> 
> A:The ViewStation FX system can be used to conduct live webcasts of
> meetings or events using streaming audio and video over multicast-enabled
> networks supporting Cisco IP TV viewer or Apple Quicktime...
> 
> Which can be found at:
> http://www.polycom.com/resource_center/1,,pw-810,FF.html
> 
> We are thinking of getting one of these to try out.
> 
> Any comments on this setup are very much appreciated.
> 
> Thanks
> 
> -Craig
> 


-- 

Regards,
Martin Clifton
---------------------------------
Communications Specialist
Networks and Computing, ITS
Victoria University of Technology
Phone:  613 9688 4579
Mobile: 0412 559 807
---------------------------------