Performing Arts Advisory

["Feghali, Jose" <>]

I should clarify a couple of things about my thoughts and experiences on this issue.

 

Of course I believe that “pushing the envelope” with uncompressed video is a very important endeavor. For people working in computing sciences and research, the state-of-the-art must surely be one of the most important priorities. I am always excited to see reports about the envelope being pushed farther, and have the hope that one day when bandwidth considerations become less of an obstacle (and less costly) that we will be able to use that technology.

 

Considering however the difficulty that we have encountered even finding DVTS partners, and after talking to a lot of people in the music area of the performing arts, it became clear that one of the most important features missing with normal “off the shelf” video conferencing equipment like Polycom (which a lot of them are using) and other non-DVTS solutions was the lack of uncompressed audio. Obviously, for music, this is a much more important priority than perfect video. ConferenceXP allows for multiple users, which also opens the door for multiple speakers/teachers from different locations to participate in the same session, like some flavors of videoconferencing and AGrid. We can for instance have a violinist, a cellist and a pianist in different places coaching a piano trio over here, or a composer from one location and a conductor from another helping out with a contemporary work’s rehearsal. If this was to be done with uncompressed video, then of course the bandwidth requirement would be virtually impossible to handle.

 

I think that ours is somewhat of a “niche” requirement compared to most commercial and other needs, in that we value better sound than perfect video – with the exception of the Opera area, where the best quality video would also be quite important. Most companies and developers appear to emphasize audio codecs which work well for voice, echo cancellation and so forth (understandable, considering that this is what the majority of their market needs). Although these are important considerations, they can lead to not provide the best sound possible. It seems that only fairly recently has “transparent”, full-frequency-spectrum audio cancellation been possible for uncompressed audio.

 

Even an institution like the Juilliard School of Music does not currently have access to Internet2, and during our tests 2 days ago we were able to do some uncompressed video and audio tests with them only because they had a spare OC line which hadn’t been disconnected yet. Previous tests, even at 1 or 2 Mbps, where a disaster. They are working towards having Internet2 access, but meanwhile the best they can do is 2 “bonded” T1 lines with a max useable bandwidth of around 3 Mbps.

 

If anyone cares to chime in with their experiences, specially if different from ours, I for one would very much like to hear your input.

 

Best,

 

JF

 

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From: Feghali, Jose
Sent: Saturday, March 08, 2008 3:09 PM
To: 'Michael C. Wellings'
Cc: ;
Subject: RE: ConferenceXP update

 

Agreed. Unfortunately, most performing arts institutions do not have anywhere near 250 Mbps available (most still run 100 Mbps Ethernet connections in their building) and such a connection here, for instance, would take up half of our available bandwidth with the Gigapop providing our Internet2 connection – assuming we replaced our current 100 Mbps routers in the music building with Gbit ones.

 

What ConfXP does now that no other solution appears to do (save maybe Vic and Rat, which are very complicated for non-technical people to use) is actually to allow for LESS video bandwidth, not more, but including uncompressed audio – thus filling a gap which exists at the moment between DVTS and normal video conferencing. Until institutions have updated their network connections and acquired Internet2 or similar connections with high available bandwidth, a lot of them here in the US but specially abroad will continue to be “bandwidth-challenged” and cannot work with DVTS, let alone dream about SD or uncompressed HD. ConferenceXP opens up the possibilities of video conferencing now with CD and higher quality audio.

 

For most of what we do in music (masterclasses, lectures, demonstrations, etc…) the 350 ms or so of latency does not really matter, and the “doubly-compressed” video (DV + WMV) is also not a concern. I am pleased however that CXP appears to have reduced the latency of the “straight” DV25 stream to about half of what DVTS displays.

 

José

 

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From: Michael C. Wellings [mailto:]
Sent: Saturday, March 08, 2008 2:54 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.

 

 

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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.

 

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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.

 

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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

 

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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

 

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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