Delivery
The digital data needs to be delivered to the end-user. To deliver images and some encoding formats of audio and video material this may require a simple file transfer; for other formats serving software must exist to retrieve the encoded material and deliver it across a distribution network at the required transmission rate to a decoder first, and then to playing software on the end-user’s computer.

Video servers are similar to traditional file servers, in that they provide digital information across a network. However, the nature of video introduces additional requirements and constraints that a file server doesnÕt have. First, video has very tight constraints for delay and delay variation (jitter).

Second, video demands substantial bandwidth for every video stream the server delivers. Thirdly, video files are very large, requiring complex storage management systems, and finally, if the system delivers interactive functionality, some mechanism for receiving commands from the end-user, such as fast-forward, reverse and other Ôtrick-playsÕ must be provided. The end-user selects an item to view and once this is confirmed as a valid request the decoding software on the end-user’s computer can request the media server to deliver it. The end-user needs to communicate what network, software and hardware capabilities they have, so that if possible the appropriately encoded version of the material can be delivered.