Streaming Media Definitions

Streaming

A process in which an application or plug-in can begin playing back the contents of a file before it is fully downloaded. Usually streaming works by downloading an initial portion of the file, known as a buffer, into the user's viewer or player. This application then begins playback of the file while the remainder continues to "fill in."

Bandwidth

Refers to the rate or amount of data that can be transferred from one point to another--usually between a Web server and an application such as a Web browser. Because of their size, multimedia files often consume large amounts of available bandwidth. Low bandwidth is a disadvantage in delivering video files over the commodity Internet.

bps/Kbps

bits per second/kilobits per second. Common units of measurement for data transfer rates. A bit (short for binary digit) is the smallest unit of computer data--a 1 or a zero. A kilobit is 1,024 bits (2 to the 10th power)

Buffered

Data that is collected but held back rather than made available. Similar to a translator on the news listening to a whole statement before telling you what the speaker has said, rather than trying to give you a less accurate, halting, word by word translation.

Codec

Compression/decompression algorithm. Programs used to convert and compress analog A/V sources into digital files then decompress them upon playback.

Encode

The process of converting media (sound, video, etc.) so it can be streamed to and played by RealPlayer

Frame rate/fps

The number of frames per second that a video file displays. A full motion video, like television broadcasting, is 30 frames per second.

Multicast

Used for broadcasting big events over the Internet. Multicasting allows a single computer to create the content (concert, film, etc.) and many computers to play the same single stream.

Sampling frequency

The number of times an audio file is quantitized, or sampled, in a given period of time. The highest pitch an audio file can produce is exactly half of the sampling rate, so higher frequencies produce better range and thus better quality audio. 22.050KHz is a common sampling frequency for computer audio files.

SureStream

Optimizes your media experience by shifting between streams encoded at higher and lower bandwidths. If there is heavy Net Traffic , RealPlayer can opt to Œdownshiftš to a stream that will have fewer problems during playback. Also, if you have a particularly good connection, or

 

if congestion clears on the net, RealPlayer can 'upshift' to a higher quality stream.