streaming video is a method, which represents a one-to-many, real-time broadcast of video and audio over the internet. it can also be transmitted over a variety of local and wide-area network implementations. it can be a live broadcast of an event or presentation, or on-demand prerecorded video (a realmedia file).

    when the term streaming video is used, it generally means audio and video combined. streaming audio is audio only.

    streaming video allows users to view audio/video content without having to download the file to their local computer. the video is "streamed" to your computer, which means the player on your side starts playing the content after a short buffering period, which can be between five to twenty seconds, depending on the video bit-rate and network traffic. the buffer allows the player to maintain continuous playback in the event of minor network congestion.

    a simple example is a "shock-resistant" portable cd player. these cd players store three to five seconds of a track from a cd in their memory, so if the player gets bumped, it doesn't skip. streaming video works the same way. the player keeps a buffer of video and if there is any network congestion, the player keeps playing without stopping. a streaming video player stores more in memory than the cd player because network congestion can be several seconds, as opposed to a bump to the cd player lasting only about a second.

    streaming media also takes into account the viewer’s connection to the internet. for example, some people have 28.8k modem connections, others have 56k modem connections, and some are directly connected via a t1 line. when you create your streaming video, you need to set a bit-rate for the target audience. you can either set a single bit-rate, such as 56k, or a bit-rate including multiple settings, such as 28k, 56k, and 100k.

    with a single bit-rate stream, only users connecting at the specific bit-rate or higher are able to view the video stream. for example, if you set the bit-rate to 56k, a user with a 28k-modem connection is not able to view the video.

    with a multi-bit-rate stream, you can create a single stream supporting multiple bitrates, so people with 28k modems can watch the stream along with people viewing the stream at 100k. to do the same with single bit-rates, you have to create multiple streams, all set to different bit-rates.

    one advantage to having multiple streams of varying bit-rates is each stream can be configured specifically for the target bit-rate. for example, a video image size of 320x240 (also known as "cif", pronounced "sif") is great for higher bit-rates, such as 100k. however, it is not a good size for lower bit-rates. a video image size of 160x120 (also known as "qcif", pronounced "q sif", or "quarter sif") is great for low bit-rate connections like 28k or 56k.

    with several single bit-rate streams, you can optimize your content for each connection speed.