Contents

Video conferences

Quite a lot of communication in the project is handled via video conferencing. Here is a (very brief) info about H.323 video conferences.

Please find a lot of description (including system tests) on the pages of the Competence Centre for Video Conference Services (VCC) at the TU Dresden. The VCC is run by the German National Research and Education Network (DFN).

Here is a brief overview for our project needs.

H.323?

H.323 is a protocol, which is used by most of the video conference systems installed in the video conference rooms in many universities (systems e.g. from Cisco, Polycom or LifeSize). They can usually also transmit in addition to the video image of the speaker the slides shown via a connected computer (with the H.239 protocol)

Video Conference Soft and Hardware

To participate in a video conference you either need a dedicated hardware system or a software solution running on your PC, a USB camera and some audio components.

Dedicated hardware system

Dedicated hardware systems are e.g. available from Cisco, Polycom and LifeSize (and several other vendors)

  • Advantages of the hardware systems
    • usually very good audio quality, especially very good echo compensation
    • easy to use
    • VGA/DVI input to transmit the slides from a computer
    • firewall administrators usually have to problems to provide an "outside network port" for the system, as it is completely standalone
  • Disadvantage of the hardware systems
    • expensive (simple systems from LifeSize start around 8000 Euro)

Software solution

Much cheaper than the dedicated hardware solution is a software solution with a USB camera and a headset. E.g. the LifeSize softphone (a demo version can be ordered there. The VCC has a test report of the software), which also runs well on the Mac. Costs for the single license is in the order of 200 Euro. Modern laptops often have a built-in camera already and headsets are cheap.

Disadvantages of the software solution:

  • not really suitable for more than one person (the echo cancellation in the software system is not very good. A headset neatly solves that problem, but limits attendance to one or few people per machine)
  • firewalls can be a real problem (unless the firewall is 'H.323 aware' and at least the addresses of the MCU systems are allowed in the firewall setup)

Cloud solution

A software solution which circumvents most firewall related issues MAY be the ClearSee solution 'via the cloud'. This system has not yet been tested by us.

Workaround: Telephone for audio / slides via the web

For cases where a participation via video conferencing is unfortunately impossible we use a telephone dial in to contribute to the discussion and AdobeConnect for access to the conference video (including the presented slides). This is, i.a. due to the additional delays for the video, not optimal, but better that "audio only".


 
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13 Aug 2014