Video-on-Demand is There for You

Joe Chow

Even though many people have heard the concept of Video-on-Demand (VoD), not many will implement this concept in education. To the commercial world, VoD may just be a replacement of the fading out video rental business. To the academia, the meaning of VoD may be more significant, representing high technology application in education. The VoD service within the campus is capable of sending or broadcasting video to individual computer. In order to achieve a more reliable and the highest possible network bandwidth separated from the data network, a video network is used. This permits high bandwidth supporting many concurrent users on the network to watch a video from the powerful video server at any time and place through the Web. With built-in features like video searching and click-to-start, the Web is designed with easy-to-use functions. No login procedure is necessary for accessing the VoD service. Furthermore, images extracted from the video are used for previewing (as illustrated below) which saves the trouble for those who are looking for specific videos.

An advantage of using the VoD service over the conventional VCR tape is that users can retrieve video instantly without being restricted by the time, such as the opening hours of the servicing counter, and place. The benefits of using VoD in the education sector are apparent; for example, seminars from other institutions, laboratory demonstration and lectures can be pre-recorded and played back at any time during a class to supplement the classroom experience. Forums or conferences held abroad could be recorded. Repetitive materials such as orientation information can be loaded on the server, and hence eases manpower limitation in arranging guest speakers.

Owing to favourable responses of VoD usage, the Computing Services Centre (CSC) had purchased a high-end video server called the SGI Origin 2000. This server, having been recognised as one of the best and most reliable server in the market, is also very popular in the commercial sector in Hong Kong.

The SGI server is able to deliver different kinds of video formats through the network, such as the most common MPEG I and MPEG II formats. Although better quality can be obtained from MPEG II format, the drawback is that it requires much more system and network resources. The MPEG I format normally requires a data transfer rate of 1.5 Mbit/sec, while the MPEG II requires at least 6 Mbit/sec and the client machine must be installed with a special MPEG II card. This is why MPEG I (or VCD) format is recommended for use.

At the user interface, an application software is deployed as shown below. You should find this software easy to use and control.

To better ensure the quality of our VoD services, it will initially be provided only to the Lecture Theatres and Room Ceres inside the CSC's Terminal Area where the service can be invoked via the CityU network menu. The VoD service, together with other services provided by the CSC, will soon be extended to every individual machine in the University.

   Computing Services Centre
   City University of Hong Kong
   ccnetcom@cityu.edu.hk