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Streaming Media is media (audio, video, or graphics) that is delivered as a stream of data, and played as it is received. It allows you to view large data files without long delays and minimal data loss as well as to view live events in real time.
The process of streaming starts when a media file is broken into smaller pieces so it can be transferred and played as each of the pieces is received, rather than waiting for the whole file to be transferred before playback starts. (This is similar to receiving and reading a serialized novel, one chapter at a time, instead of waiting for the whole book to arrive before starting to read it.)
How quickly you can receive files depends on your Internet bandwidth (more information on bandwidth below). One of the features of RealPlayer is that it can select a data stream that best matches your available bandwidth (some media is streamed at more than one bandwidth), so the media stream provided matches the transfer (download) speed available to you.
RealPlayer can also display media created in Synchronized Multimedia Integration Language (SMIL) protocol, which is used to better optimize the bandwidth of a presentation. SMIL presentations send different streams for each of the components of a presentation (for example: a video stream, audio stream, and text stream). Each stream has a different optimum bit-rate associated with it. The result is that a complex presentation can be streamed with a much lower bandwidth than if the whole presentation were limited to the format and bandwidth of the largest media type.
The property that most affects your experience playing any type of streaming media over the Internet is bandwidth. Usually this means the maximum speed (Kbps) of your Internet connection, but it can also refer to capacity of the media server (how many data streams the server can provide), as well as other network constraints.
If RealPlayer had to download data faster than your connection can handle, such as viewing a 256Kbps stream over a 56 Kbps connection (you can see the bandwidth of any stream on your Status Display), the presentation would have to regularly pause to let the system catch up. To avoid this, a media provider can stream RealAudio and RealVideo in multiple bandwidths at the same time, such as at 56 Kbps and at 256 Kbps. RealPlayer will choose the data stream with a bandwidth that best matches your Preferences. A narrower, or lower bandwidth, data stream will be of lower quality, but it is less likely to be interrupted than a wider data stream.
When media is being streamed, the bandwidth does not always remain constant. Often it will fall below what is required to stream the presentation smoothly. To avoid pauses because of delays or slow transmissions, RealPlayer will cache, or buffer, a portion of the media stream before beginning to play it. (This is indicated by "Loading xx%" in the Status Display when you start playing a clip.)
When the bandwidth through your connection is low, or data drops, RealPlayer takes data from the buffer. When bandwidth returns to normal, RealPlayer puts data into the buffer until the cache is refilled. When you attempt to view a high-bandwidth clip over a low-bandwidth connection, RealPlayer will attempt to create as large a buffer as possible before beginning playback.
Streaming Media: Media that is being presented on the Internet. The data stream originates on the Internet, is transferred by modem to your computer, is decoded by a media player, and is then viewed by a consumer.
Recorded Media: Data files that are directly accessible from your computer (on a hard drive or network drive) such as audio CD tracks on a CD, or .RM or .MP3 files.
Note: For the purpose of this discussion, streaming media refers only to media that is arriving from the Internet. Technically, media that is played from a local drive (recorded media) is still being streamed to the RealPlayer software, but this process is much faster than media that is arriving from the Internet.
On-Demand Media: A media file that is available on the Internet and is streamed to your computer. Typically it is an audio or video clip that you can select and listen to from start to finish.
Live Streaming Media: An audio or video stream that is being data-cast live and is available continuously. Typically these are Internet radio or TV stations.
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