Performing Arts Advisory

["Feghali, Jose" <>]

I should correct something I wrote before about ConferenceXP, which was in 
error. As it is now, ConfXP is *not* capable of real HDV conferencing. What I 
thought was HDV was actually "normal" DV at 16:9 resolution. When setting an 
HDV camera to output HDV through the firewire connection, CXP does not 
recognize it. 
 
As Mike noted here before, HDV adds at least another 500 ms of latency and is 
probably not a good medium for real-time conferencing in any case.
 
The latest CXP code at Codeplex includes the fix I found for the uncompressed 
audio problem, and an audio buffer setting window that helps to sync the 
audio with the video.
 
JF

________________________________

From: Michael C. Wellings 
[mailto:]
Sent: Sat 3/8/2008 2:53 PM
To: Feghali, Jose
Cc: 
;
 

Subject: RE: ConferenceXP update



The DV CoDec  
(http://www.nssn.org/search/DetailResults.aspx?docid=280521&selnode=) does 
frame-based compression at 25mbps.  Uncompressed SD video varies between 100 
and 250 mbps depending upon the sample format.  Current standard 
broadcast/production data rate is 250mbps.  The point of transporting 
uncompressed video (SD in this case) is to lower the latency.  DV compression 
adds 100 or so ms per end.  For arts-related use lower latency would be 
pretty important.  The point is to get ConferenceXP to transport video at 
uncompressed rates...indeed at a suite of rates...to make it more scalable 
and useful for multiple applications. I really appreciate your continued 
interest in ConferenceXP and ip video...it's really important for us to 
understand the needs of the community and to engage others in continued 
development

 

mike

 

From: Feghali, Jose 
[mailto:]
 
Sent: Saturday, March 08, 2008 12:43 PM
To: Michael C. Wellings
Cc: 
;
 

Subject: RE: ConferenceXP update

 

What I am saying is that ConfXP appears to do what DVTS does - i.e. send the 
firewire DV stream from the camera out via IP uncompressed by a codec on the 
computer. 

 

I know that the DV codec has "theoretically" got some compression on it, but 
I got the same data rates for both DVTS and ConfXP. I have not dealt with any 
*really* uncompressed video format and do not intend to experiment with 
uncompressed HD or other "cutting edge" technologies anytime soon.

 

 

________________________________

From: Michael C. Wellings 
[mailto:]
 
Sent: Saturday, March 08, 2008 2:35 PM
To: Feghali, Jose
Cc: 
;
 

Subject: RE: ConferenceXP update

 

That data rate is too low to be uncompressed SD video.  What is your input 
format? Must be compressed...

 

From: Feghali, Jose 
[mailto:]
 
Sent: Saturday, March 08, 2008 12:33 PM
To: Michael C. Wellings
Cc: 
;
 

Subject: RE: ConferenceXP update

 

About the same as DVTS - almost 30 Mbps with video and audio (around 25 Mbps 
just video) using DV.

 

________________________________

From: Michael C. Wellings 
[mailto:]
 
Sent: Saturday, March 08, 2008 2:31 PM
To: Feghali, Jose
Cc: 
;
 

Subject: RE: ConferenceXP update

 

What is your output data rate?

 

From: Feghali, Jose 
[mailto:]
 
Sent: Saturday, March 08, 2008 12:20 PM
To: Michael C. Wellings
Cc: 
;
 

Subject: RE: ConferenceXP update

 

Under video settings, you can choose "uncompressed video" in the advanced 
box. It switches off the Windows Media encoding engine.

 

________________________________

From: Michael C. Wellings 
[mailto:]
 
Sent: Saturday, March 08, 2008 2:18 PM
To: Feghali, Jose
Cc: 
;
 

Subject: RE: ConferenceXP update

 

I understand...fred mentioned you.  What hasn't been there is support for 
multiple codecs, and for uncompressed HD video.  We are looking at the 
ConferenceXP front end for iHDTV.

 

ConferenceXP natively supports Windows Media encoding...what support for 
uncompressed video are your referring to? 

 

From: Feghali, Jose 
[mailto:]
 
Sent: Saturday, March 08, 2008 12:13 PM
To: Michael C. Wellings
Cc: 
;
 

Subject: RE: ConferenceXP update

 

Michael,

 

I have been in touch with Fred Videon at your CS department and Paul Oka at 
MSoft on this over the last few weeks. According to Fred, the code changes I 
made which allow for uncompressed audio without glitches and for synching 
audio and video will be incorporated into CXP version 5.0. 

 

Uncompressed video has always worked, and HDV also worked yesterday. In order 
to get DV and HDV to work properly with ConfXP, one needs to "downgrade" to 
Windows Media 10, as there appears to be a problem under Windows Media 11 
which doesn't allow for compressed video in CXP.

 

José

 

________________________________

From: Michael C. Wellings 
[mailto:]
 
Sent: Saturday, March 08, 2008 1:26 PM
To: Feghali, Jose; Petr Holub; 

Cc: 

Subject: RE: ConferenceXP update

 

Jose

Along with our CS Department we got the grant from Microsoft Research to 
continue development work on ConferenceXP.  In a mtg the other day we 
discussed this prospect as well as plugging live HDV into ConferenceXP, and 
opening it up to other CoDecs and - Uncompressed video.  If there is interest 
in the community to do this is may help with the decision process

 

mike

University of Washington

 

 

From: Feghali, Jose 
[mailto:]
 
Sent: Saturday, March 08, 2008 10:20 AM
To: Petr Holub; 

Cc: 

Subject: RE: ConferenceXP update

 

I tried RAT a while back and couldn't get it to work right uncompressed.

 

Do you know what is the max resolution that VIC supports? Is there a FAQ that 
you know of that explains how to setup RAT and VIC for IP-to-IP conferencing?

 

Thanks,

 

José

 

________________________________

From: Petr Holub 
[mailto:]
 
Sent: Saturday, March 08, 2008 12:14 PM
To: Feghali, Jose; 

Cc: 

Subject: RE: ConferenceXP update

 

RAT from MBone Tools (or AccessGrid) can do also uncompressed audio at this 
level.

 

Petr

 

================================================================

                            Petr Holub

CESNET z.s.p.o.                       Supercomputing Center Brno

Zikova 4                             Institute of Compt. Science

162 00 Praha 6, CZ                            Masaryk University

Czech Republic                     Botanicka 68a, 60200 Brno, CZ 

e-mail: 

               phone: +420-549493944

                                             fax: +420-541212747

                                       e-mail: 


 

From: Feghali, Jose 
[mailto:]
 
Sent: Saturday, March 08, 2008 6:28 PM
To: 

Cc: 

Subject: ConferenceXP update

 

Colleagues,

 

We have know successfully tested ConferenceXP with uncompressed stereo audio 
(16/44.1 and 16/48) using both compressed and uncompressed video. The latency 
with all uncompressed appears to be lower than DVTS, but there is some 
question as to the video quality. One of the testing sites reported the video 
being slightly less sharp with ConfXP using an HDV camera. It appears that an 
optimum bandwidth with compressed video/uncompressed audio is in the order of 
around 2.5 to 3.5 Mbps, but we have gotten good results down to around 2 Mbps.

 

If there are any other performing arts institutions or others that would like 
to test ConfXP in full uncompressed audio with or without compressed video, 
please get in touch with me off-list at (j DOT Feghali AT tcu DOT edu). 

 

If anyone here knows of any other conferencing solution currently available 
that allows for full, 44.1/48 KHz uncompressed audio to be paired with 
compressed video I would appreciate the input.

 

José Feghali

Artist-in-Residence

Coordinator of Internet Technologies

TCU School of Music