RealSystem 8

RealSystem, also known as RealAudio and RealVideo, is a network-oriented, streaming media architecture developed by RealNetworks. This architecture supports both server-based "true streaming" and serverless "download". A server (available from RealNetworks) is required for the best user experience.

RealSystem is most appropriate for network delivery of audio, video, and other media types such as text and Flash animations. It is less often suitable for CD-ROM or DVD delivery due to the high CPU requirements at higher bandwidths. RealMedia files cannot be edited or re-compressed once they have been encoded.

Users can view RealMedia files with the RealPlayer, a free "client" application available from RealNetworks. The enhanced "RealPlayer Plus" provides additional features, and must be purchased from RealNetworks. A Netscape plug-in is also available, but most developers include Real content on their site so that it is viewed with the RealPlayer.

RealSystem supports SMIL ("Synchronized Multimedia intergration Language," pronounced "smile"). This language enables RealSystem to synchronize media and actions within a Web page in addition to video and audio. For example, SMIL can control loading multiple movies at given times, URL page flips, transitions, text tracks, and more.

The latest free downloads, as well as more information, are available at RealNetwork's site.

When used with a RealServer, RealSystem offers strong scalability through a variety of features. Real's SureStream feature allows you to create up to eight versions of your audio and video tracks which are specifically encoded for common user connections.

During playback, the RealPlayer and RealServer continually communicate and can repeatedly switch between versions to deliver the highest-quality stream that the viewer's connection can support at any given time. This real-time switching effectively handles changing network conditions, such as congestion. Switching of audio and video is handled independently, and you can indicate whether the video or audio should be given preference as the viewer's throughput drops.

In addition to the SureStream feature, the RealPlayer can also drop frames and/or degrade the image quality to maintain real-time playback over slower connections. In extreme cases, the RealPlayer can omit the video track entirely and simply play the audio track.