This report is also available as an Acrobat file.
SUN Hardware and Software for Videoconferencing
In this chapter, we describe the videoconferencing tools used in the project in some detail
since we feel that this will give the reader a good idea of what constitutes a desktop
videoconferencing system and will provide a reference system for comparing with other
For this project, we used four SUN Sparcstation IPX systems, which are Sparc 2 based, and
one SUN Sparcstation ZX system, which is Sparc 10 based and contains a graphics
accelerator. Four of these SUN workstations were located in offices of members of staff and
one on the HelpDesk. We upgraded these workstations using multimedia upgrade kits from
SUN. The kits consisted of:
The workstations we possessed already had audio support in the form of:
- SUN camera
- This can be attached to the top of the workstation and can
swivel up and down, left and right. It has a lens shutter
it is more reassuring for visitors if this is closed when the
camera is being used!!
- SUN video card
- This takes up a single SBus slot. It is used to capture and
compress and transmit video data. More details are given
later in this section and in Appendix 2.
The videoconferencing software required was:
- SUN microphone
- This could be attached to the SUN workstation. However,
it was recommended that the microphone should be as far
away from the speaker as possible to prevent feedback.
Even if there is a separate speaker box, the microphone
should be detached from the workstation since it may pick
up the background hum of the workstation.
- SUN built-in speaker or box
- The IPX workstations have built-in speaker hardware but
the ZX workstations have a separate speaker box.
- SUN XIL library
- This has low level functions to control applications which
take advantage of the SunVideo system.
- SUN ShowMe Version 2.0
- More details on ShowMe are given later in this section.
The SUNVIDEO System and the XIL Programming Support
SunVideo is a real-time video capture and compression subsystem for Sun SPARCstations.
It includes a SunVideo card which supports the capture, compression, storage and
transmission of video images. SunVideo is designed to work with the facilities of the SUN
XIL 1.1 Imaging Library which provides functions for image processing and image
compression/decompression. XIL programs when used with SunVideo take advantage of the
compression engine of the video card. So the compression rates are a function of the
performance of the SunVideo card.
Decompression of video on a receiving workstation is done totally in software since this
particular video card has no decompression functions. Applications such as Showme can
access the decompression functions in the XIL library. This has the advantage that a
workstation does not need a video card installed in order to receive video but the
disadvantage that video performance is partly dependent on the CPU performance of the
receiving host. As we found, this can be significant when the receiving workstation is a PC
running an X emulator connected to a multi-user host.
Please refer to Appendix 2 if you are interested in the more technical details of the SunVideo
card and the XIL library.