Video streaming is the process of transmitting a digital video file in realtime over the Internet for display on your PC. As the name suggests, the data is streamed from one point on the Internet to another and is displayed while it is streaming. In video streaming, there is no need to download the video file prior to playing it. As such, video streaming is also often used to display a live view from a security cameras.

RTSP/RTP is the primary video streaming technology used in selecting a digital video recorder (dvr). Unfortunately, even when a DVR manufacturer uses RTSP/RTP as the underlying protocol for streaming live and recorded video, their product is usually not compatible with a product from another manufacture.

The incompatibility between one manufacture's video streaming technology and another's is the result of three factors.

   It is not often in the interest of a DVR manufacturer to make their video streaming implementation compatible with other DVR manufactures.

   A video streaming implementation for selecting a digital video recorder (dvr) is by necessity tightly coupled with the way video data and security events are stored. Unfortunately, no widely adopted protocol for accessing video surveillance data exists. For example, the RTSP protocol has no specification for retrieving motion detection events. That said, a number of DVR manufactures do provide access to their systems via a software development kit (SDK).

   Those companies providing a video streaming server that is compatible with well known players (QuickTime, Windows Media Player, Real Networks) are generally doing so for the consumer market (not the video surveillance market). These video streaming servers are used to stream movies or news broadcasts. Were a DVR manufacturer to provide the same functionality as video streaming servers for broadcasting television content over the Internet, the manufacture's will run into licensing hurdles with the original software developers of the streaming code.

Finally, note that video streaming is not the same as video compression. Many manufactures provide video compressed into a common format (MPEG-4) that is compatible with standard video players.

For a good overview of streaming technologies see: www,cswl,com/whiteppr/tech/StreamingTechnology,html.