Streaming video provides a continuous digital video and/or audio signal across a data network. As a viewer, you typically make a web browser-based player connection to a streaming server to receive a webcast (live program) or video-on-demand (previously recorded program). The program is sent from the server to your player in a continuous fashion, as opposed to having the entire program downloaded before viewing can begin. Viewing begins much quicker with streaming. No copy of the entire program is stored on the computer being used for viewing.

In the following graphic, the blue cylinder represents a server and the tan rectangle a personal computer. The top line shows the process for the typical file transfer: request asset, receive entire asset, then play asset. The lower line shows the process for streaming: request asset, start transmission, start playing, continue sending "chunks", end transmission, end playing.

Each viewer receives their own stream from the server, so bandwidth can be an issue for popular webcasts. The same video-on-demand program can be started at any time by different viewers.

The ITS Streaming Video Service supports MPEG, MP3, QuickTime, Real, and Windows Media for video-on-demand. MPEG-2 is only available for on-campus viewers (because of bandwidth requirements). Webcasting is currently being offered in Real and QuickTime.

Which convention to select depends on several factors, including audience location, what streaming players your audience is most comfortable using, and what tools you are most comfortable using in preparing a streaming program. ITS is investigating transcoding equipment that would allow us to record/store in one format, but deliver multiple formats in real-time.

The following is a quick explanation of some of the basic terms you will encounter in streaming media discussions.

CO-DEC - a COmpression-DECompression algorithm used for efficient storage and transmission of a data file, such as a video or audio file.

MPEG - the Moving Picture Experts Group defines industry standards for the encoding, management, and delivery of content through various media.

MPEG-1 - a codec designed for near-VHS quality video. MPEG-1 is primarily designed for CD-ROM delivery of content through various media.

MPEG-2 - a codec designed for high-quality video. MPEG-2 is primarily used for DVD disc encoding and other high-quality archival solutions, but can be streamed over high-bandwidth connections, such as Internet2. MPEG-2 playback often requires additional software and/or hardware.

MP3 - a codec designed for audio. MP3 is the most popular standard used for distribution on the Internet and in portable music players, such as Apple’s iPod. Note that MP3 stands for MPEG Audio Layer 3, not MPEG-3 (there is no MPEG-3).

MPEG-4, QuickTime, Real, and Windows Media are all streaming media architectures. They can handle a variety of media such as audio, video, text, animation, and 3D. They also support some forms of metadata (information about the media asset) and interactivity.

MPEG-4 - built around non-proprietary codecs, MPEG-4 excels at multi-architecture compatibility. Future codecs should enhance quality.

QuickTime - built around several non-proprietary codecs, QuickTime excels at medium to high bandwidth clips. It supports MPEG-4.

Windows Media - built around proprietary Microsoft codecs, Windows Media excels at medium bandwidth clips. It does not support MPEG-4.