|PPNCG Information Pages : Video-conferencing : Desktop videoconferencing recommendations (PPNCG)|
|The second edition (now distinctly dated) of the PPNCG's recommendations for desktop-based videoconferencing is available at
It is by now VITAL that you read the notes linked below
(Notes to the 2nd Edition PPNCG recommendations ) before relying
on anything you read in those earlier recommendations.
Note that all the 'business-class' solutions known to us are based on Windows operating systems (whether 9x, NT, 2K ...), and users pretty much have to live with that. I would recommend installing an X server such as eXceed or Cygwin/X, so that you can also access your favourite Unixoid systems - and, where data sharing is in use, can also share those windows with other participants.
In addition to the kit mentioned below, of course you are expected to
supply a suitable PC with a suitable operating system.
|To add versatility (and confusion) to the mix, however, there _is_
also the VRVS, http://www.vrvs.org
which allows interworking between users of the IETF software-based
videoconference protocols (vic, rat...) and users of H.323.
When using the IETF software-based protocols (with vic and rat
as distributed by the VRVS project) you would want a camera of a
type which is supported by your OS's multimedia layer.
This might be a web-camera (nowadays often USB-connected), or
for somewhat better quality a PCI-based video capture card and
|The Polyspan "SoundPoint/PC" is an inexpensive accessory that's well worth
getting with any PC-based videoconferencing arrangement.
It's a sort-of "speakerphone", with a built in echo canceller,
specifically for use with PC audio.
In Glasgow we have several of these, and they are well-used.|
2003-Dec-11 14:42 firstname.lastname@example.org
|ONGOING ISSUE - new software-based H.323 applications
There are now some new software-based solutions becoming available based on the OpenH323 implementation. For example GnomeMeeting.
Software codecs are generally considered to be unacceptable in "business class" multipoint meetings: at any rate, users are cautioned not to attempt to use them without due liaison with whoever manages the H.323 MCU that is to be used. (In the case of point to point meetings you can obviously argue the acceptability issue with your partner site...)
VRVS users in such a situation would be better advised, we think, to use the IETF-protocol applications i.e vic and rat, rather than trying to use the VRVS's H.323 compatibility mode and their software-based H.323 client.
Having made those general remarks, however, it does seem as if
GnomeMeeting is developing a good reputation, and consent for
pilot use on ESnet ad-hoc H.323 has been granted.
|[Add a New Answer in "Desktop videoconferencing recommendations (PPNCG)"]|
|PPNCG Information Pages : Video-conferencing : Desktop videoconferencing recommendations (PPNCG) : Notes to the 2nd Edition PPNCG recommendations|
|H.323 solutions fall into
two main categories: those based on hardware codecs, and those based
on software codecs.
In our community, the only widely-tried H.323-based software-codec solution had been MS NetMeeting, used with an inexpensive PC-camera and with either a headset or the SoundPoint/PC echo canceller. There's no disagreement that this is a usable technique when used for personal videoconferencing between consenting participants; the arguments have been about its use in group-sized "business class" multipoint H.323 conferences.
In the past, Netmeeting definitely *has* caused disruption of otherwise satisfactory multipoint conferences due to major audio defects (echoes, noises, and a kind of "motorboating"), and there have also been claims that the use of Netmeeting is implicated in crashing H.323 MCUs.
More recently, OpenH323-based packages such as GnomeMeeting have become available. Again, for point to point use if the participants can make them work then fine, but for multipoint meetings the caveats apply.
The use of software-based codecs such as Netmeeting isn't allowed on the ESnet MCU, nor in H.323 Megaconferences.
There seems little doubt that the use of hardware-codec based H.323 solutions
is very much to be recommended, whatever one's feelings might be
on the possibility of a fallback onto software-based solutions when no other
facility was to hand. Be aware however that H.323 hardware codecs
(Zydacron, ViaVideo etc) are dedicated devices; they are not in general
suitable for arbitrary video capture purposes, such as use with the 'vic' application, webcam, etc.
|Already at the PPNCG's meeting in early 2002, the recommendation for
the Zydacron was "frozen". The product still works, no less than it ever
did, and one of ours is actually QA-tested and accredited to the JANET
videoconferencing service, but at the lower edge of what they would
consider adequate for participation in their service.
Those who already have Zydacron units may of course continue to use them, but look out for notes on incompatibilities and work-arounds in some situations.
The recommndations for 'business-class' H.323 conferencing were:
* (PPNCG RECOMMENDATION NOW FROZEN:) For an extensible group system, the PPNCG had recommended the Zydacron OnWAN solution, based on the Z353 PCI card (a development from the Z350 card, functionally equivalent as far as we are concerned).
* For a relatively portable personal system, that can be swapped around between desktop machines and laptops as required: the Polycom/Polyspan ViaVideo (USB-connected). This is less than half the cost of the Zydacron card, but what you get is essentially all that you get: there are no options for upgrading video inputs etc.
Updating this article as of Oct 2003, one can say that the ViaVideo units have been a success story, for the personal workstation situation. However, they don't take an external video input.
The then-current VCON ViGo product had been assessed at the time, and rated as poorer value than the ViaVideo; however, it appears that there's a new model of the product out now (2003) in the Americas, and some good reports have been heard. It costs, it seems, roughly 50% more than the ViaVideo, but it does accept external video input. The product has a number of other attractive features. Since the offering hasn't been directly assessed by, or on behalf of, the PPNCG, we can't make any specific recommendations here, but it seems worth considering, at least when the new model is available in Europe. http://www.vcon.com/solutions/videoconferencing/desktop/ViGO/index.shtml
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|PPNCG Information Pages : Video-conferencing : Desktop videoconferencing recommendations (PPNCG) : The Zydacron OnWAN package|
|a) Zydacron OnWAN package, based on Z.350/Z.353 PCI card.
The original recommendation is now "FROZEN", but we have not been able to make a specific recommendation which can replace it in terms of a group-sized facility.
The kit had cost us GBP995 plus vat. that's for the PCI card, kit of connectors and basic golfball camera. You have to supply your own PC of course, and the software is Windows-based.
This forms the basis of a fine group-based system, which is perfectly usable in the form supplied, but which can later be enhanced with better camera, microphones, document viewer as required, and can accept other analogue video inputs such as videorecorder, camcorder etc. (S-Video or composite video signals).
This supports both H.323 (IP videoconferencing) and ISDN2 (the more traditional H.320 videoconferencing), although, as we don't have an ISDN line, the latter option isn't useful to us. Zydacron do produce a card that lacks the ISDN option, but the price saving was not significant.
The newer Z.353 card was recommended, as it is physically shorter than
the older Z.350 version of the card, but functionally they are pretty
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|PPNCG Information Pages : Video-conferencing : Desktop videoconferencing recommendations (PPNCG) : Polycom ViaVideo|
This is a USB-connected H.323 subsystem, costing around GBP400+vat. It's usable as a personal or small-group system. However, the echo-canceller is based on the built-in microphone. There are no options for external video inputs, you have to use the beast's built-in camera and microphone (or a headset).
On the other hand, it is a quite neat little beast, and because it's
USB-connected it can be easily moved between PCs: it also works well
with a suitable laptop.
|ViaVideo software versions:
Version 2.2 is quite old, but works reasonably well.
Version 3.0 is *not recommended* for use in our community. It is incompatible with the VRVS, and also has caused problems with RadVision MCUs (such as are used for the ESNet "ad hoc" H.323 service).
There does not seem to be a version 4 at all. The next version after 3.0 is 5.
Version 5 is available, and some folks have had reasonable results with it.
Some users complain bitterly about its user interface. If you thought version 2.2 was bad then you'll hate version 5.
More to the point, however, some users who have tried version 5 have had unexplained difficulties in connecting to some gatekeepers and MCUs, in ways which version 2.2 had no problem with. At the moment I'm in no position to advance any theories about why this was happening - whether user inexperience, real software incompatibilities or what.
There seems to be no provision for having more than one version of the viavideo software installed at the same time.
(And, just in case anyone is still running Windows NT/4, I should
add that whereas ViaVideo 2.2 supports NT/4 reasonably well, there
is no sign of support for NT/4 in their version 5 software.)
|There's a security alert, reference 02-002, relating to the
viavideo's web management interface.
This patch is applicable not only to version 3 software (which we don't recommend anyway, see above), but also to version 2.2.
Those of a more conservative nature might prefer to firewall port 3603.
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|PPNCG Information Pages : Video-conferencing : Desktop videoconferencing recommendations (PPNCG) : "Cheap and cheerful" video kit|
|This section relates to video suitable for use with the VRVS etc.
(i.e not for hardware-codec H.323).
The PPNCG was previously recommending the Winnov Videum kit for this purpose, for example the kit which is marketed as "Videum Conference Pro PCI kit": it did indeed seem to be better technically than many of its contemporaries, but whereas prices for this sort of gear have fallen generally, the Winnov kits had maintained their price, and as a result they now seem uncompetitive for our purposes.
It seems to this writer that the choice really now (2003) comes down to *either* paying a little more and getting a dedicated H.323 hardware codec solution if that fulfils the user requirements: as a minimum solution that would be the ViaVideo, which can be used with both H.323-only conferences and in H.323 mode with the VRVS (but limited to a Windows OS). *Or* to get whatever inexpensive USB-connected web camera happens to be available, in which case VRVS users would probably want to use vic/rat modes, although linux users still have the option of using Gnomemeeting for software-codec H.323 - but keep in mind that, aside from point-to-point work with consenting partners, your multipoint options, aside from the VRVS, are likely to be quite limited.
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