Compaq ProLiant 1600 Video Streaming Technology - Page 14

ECG068/0798 WHITE PAPER (cont.) 1...4 Internet since individual packets may take different paths and arrive at different times at the destination. In some cases, packet errors or lost packets may also result in re-transmission causing disruption of the video. On Intranets such as shared Ethernet video packets may also have to contend with other data traffic such as file transfers, database access, access to shared modem and fax, etc. The continuous streaming data needs of video are difficult to meet in this type of environment. A network is called "isochronous" if it provides constant transmission delay and "synchronous" if it provides bounded transmission delay. For the latter, isochrony can be achieved with a "playout" buffer. Synchronous Data Packets (Variable delays with upper bound) Playout Buffer Isochronous Data Packets (Constant delays) Achieving Isochrony with a Playout Buffer One way to achieve this effect is to insert time stamps and sequence numbers in the video data packets so they can be properly assembled and played out of the receiving buffer. Over IP-based networks such as the Internet, a new protocol called "Real-Time Protocol" (RTP) has been developed to accomplish this. Video Streaming System A complete video-streaming system involves all of the basic elements of creating, delivering, and ultimately playing the video content. The main components of a complete video streaming system to accomplish this-Encoding Station, Video Server, Network Infrastructure, and Playback Client-are illustrated in the following diagram. 1. Capture Encoding Station 2. Edit 3. Encode 4. Serve Video.AVI Video.ASF Edit AVI or ASF files Specify: Data Rate Resolution Frame Rate Codec Type Network Video Server Intranet: 128Kbps Internet: 28.8bps Video Editor 5. Play Client Station • P