4. Different Kind of System

Videoconferencing equipment might be grouped into classes according to which type of hardware that is integrated, and the cost for purchasing them:

• Large group sized systems (10.000 - 40.000 euros)
• Medium and small sized group systems (5.000 - 10.000 euros)
• PC videoconferencing solutions (200 - 5.000 euros)
• Professional videoconferencing systems include the two first categories.

The improved H.264 video standard has been implemented into the hardware of the large, medium and small sized videoconferencing systems since approximately the summer of 2003. This standard offers XGA resolution and twice the transmission quality of video at bandwidths up to 768 Kbps.

Notice that the previous H.263 standard did only offer VGA resolution, and that a transmission speed of 384 Kbps at H.264 is equivalent to 768 Kbps at H.263. It is not possible to update the software of a H.263 system in order to achieve H.264, as the hardware must be updated too.

The bandwidth is one of the critical issues for the quality. However, the processing capacity of the CODEC also influence quite heavily on the final output. It is two important factors to be aware of:

• The number of pictures transmitted per second
• The audio quality

Large group sized systems

These systems are designed for use within large rooms and in large audiences, for instance meetings with a lot of people participating and training sessions within auditoriums. Key features include:

• Call up to 6 sites on video and 5 sites on audio
• Watch the presenter and the presentation simultaneously through 2 separated video streams (H.239)
• Network connections include selection of up to 6 Mbps in a multisite call, 4 Mbps on IP (H.323) and 2 Mbps on ISDN
• H.264 and XGA
• Very good processing capacity, whereby they are well suited delivering distance training

Medium and small sized systems

These systems are designed for use within medium sized rooms and in minor audiences, for instance meetings with a limited number of people participating and training sessions within medium sized rooms where a projector is used. Key features include:

• Call up to 4 sites on video and 3 sites on audio
• Watch the presenter and the presentation simultaneously through 2 separated video streams (H.239)
• Network connections include selection of up to 2 Mbps on IP (H.323) and 512 Kbps on ISDN
• H.264 and XGA
• Easier to transport and interconnect than the systems which are adapted to large size rooms
• The processing capacity is reduced as compared with the large group systems, whereby they are well suited receiving distance training in an endpoint

PC videoconferencing solutions

These software-based systems are primarily designed for use between PCs, and offer a cheap solution for two-way real time communication through a dedicated camera or a web-camera and a graphical interface on the PC. They offer a cheap solution for starting with videoconferencing.

PC videoconferencing is far away from satisfying the quality offered by professional videoconferencing systems. It is particularly issues related to quality, stability, flexibility and security that is limits the deployment of videoconferencing at PCs.

In order to run a videoconference at the PC, it requires relatively large processing capacity, whereby it limit how many other programs that might be active.

The Web-camera is connected to the PC trough the USB port. The most expensive Web-cameras offer software tools offering applications for digital pictures and digital video. In order to run a videoconference, a special software program like Microsoft Messenger or Skype, is needed.

It is usually easy to initiate conference calls, but due to limited resolution within the web-cameras and poor capacity on the audio (the PC microphone and loudspeaker), the usage is limited towards communication between single users or small groups. It is necessary to use head microphones in order to avoid noise on the audio.

This solution is convenient for one-to-one calls between single users, e.g. private persons.

Key features include:

• Graphical user interface on the PC
• H.264 video (not from all vendors) with XGA resolution
• Modern PC with large processing capacity
• Integrated camera (e.g. ViaVideo II) or Web-camera