Streaming video is what most people heard of, but have no idea what it is. This is the content that is sent through the Internet in compressed form and watched by the end-users in real time. The main difference between traditional online video watching is that streaming video or streaming media are opened instantly – a user doesn’t have to wait until they download. Media information is sent in the form of data stream and is played just as it arrives. The only thing a user needs is a video player that will decompress content, sending data to display and speakers. Such player may be either integrated into browser or be the software on webmaster’s site.
Major technologies for video and media streaming are RealSystem G2 of RealNetwork production, Microsoft Windows Media Technologies with their NetShow Services and Theater Server and VDO. In Microsoft's approach a conventional MPEG video compression algorithm is applied. Plus, there are some proprietary algorithms used. Codec program is applied as well: it performs compression and decompression. For the majority of users, streaming video is limited to the data rates of the connection (for instance limit for ISDN connection is 128 Kbps). Microsoft's streaming media data comes in Advanced Streaming Format (ASF).
Streaming video may be in the form of preliminarily recorded video files, or come as part of live broadcast (also called "feed"). In the second case, video signal is transformed into compressed digital signal and broadcast from special Web servers capable of multicasting, e.g. sending the same file to several users simultaneously.
How does CDN help in video streaming? If a site contains a lot of large video files, users located geographically far from host place may experience high latency, troubles with downloading, low speed, jitters and other problems. Distributing the content between several servers located in different areas, webmaster provides faster and easier access for users, making their experience flawless and more enjoyable, because content delivery quality greatly increases.