With this kind of facility in action, you are not limited to a few specific applications (chat, whiteboard, powerpoint etc.), but you can share just any application windows on your display - even the entire desktop if you wish. In appropriate situations, you can grant control of the applications to other conference participants.

Remember that although the videoconferencing platform is typically Windows, it's still possible from the same PC to get X windows from a remote Unix-style system by means of an X server like eXceed or Cygwin/X, and then to include those windows in the conference application sharing. Thus you could include (say) not only your PowerPoint presentation window, but also the real live window of your Unix-based Physics application on screen, while still speaking to camera. This is _so_ much better than trying to point the camera at a projector screen, and have the distant viewers peering at a poorly focussed and low-contrast video image of a projection of your presentation (and losing sight of all your eloquent gestures)!

(Of course, if you have more than one PC then you might use one for the audio/video conferencing and another for the shared application windows; but here I'm concentrating on techniques/tricks for working out of a single PC.)

1) T.120 using the data sharing component of Netmeeting

T.120 is the data sharing specification that's included in the H.323 IP videoconferencing framework. The data sharing component of Netmeeting is the usual way of sharing ("MS-Windows") application windows in this context. Much of the remaining sections of this page deal with that approach, but there are others.

2) The data sharing feature of the "Latitude" MeetingPlace server.

This is the option chosen by the ESnet ECS service, see http://www.ecs.es.net/audio-docs.html and the vendor site at http://www.latitude.com/

3) vnc

vnc is a cross-platform application sharing framework which has no specific relationship with videoconferencing: it has been used and proven in practice in many different situations, having nothing to do with T.120 nor even with H.323. Its particular relevance to our situation is that it was selected by the VRVS as the supported method of sharing application windows in their videoconferencing system, http://vrvs.org

2003-Dec-11 20:06 a.flavell@physics.gla.ac.uk

Answers in this category:
1) Datasharing component of Netmeeting
2) Latitude MeetingPlace at ESnet ECS
3) Application sharing with vnc at the VRVS

One should be aware that Netmeeting data sharing, like any other means of exchanging files, represents a possible route of infection for viruses, trojans etc.

Also, configuring Netmeeting to automatically accept incoming calls could leave one open to intruders.

The usual kinds of precautions should be taken against these potential risks.
2001-Sep-30 23:10 a.flavell@physics.gla.ac.uk