Streaming Media - Industry Terms

Analog
Analog technology refers to electronic transmission accomplished by adding signals of varying frequency or amplitude to carrier waves of a given frequency of alternating electromagnetic current. Broadcast and phone transmission have conventionally used analog technology. An analog process, as a continuous wave, rather than digitally in a binary form, produces standard audiotape and videotape recordings.

ASF
Most streaming media files encoded for use on the Windows Media platforms have an asf extension. This is an actual audio/video file, as opposed to an ASX file.
Broadband Used to describe a network connection, which supports a relatively high bitrate. Also used to describe content, which takes advantage of a high bitrate connection.

Buffering
Describes a situation, which occurs when a streaming media player is saving portions of a streaming media file to local storage for playback. Most streaming media players buffer a small percentage of a streaming media presentation before beginning to play it. Buffering also may occur in the middle of a presentation, when available bandwidth does not match the presentation's required bandwidth.

Bit
The unit of information. A computational quantity that can take on one of two values. The smallest unit of storage sufficient to hold one bit. It is the answer to a yes or no question or in terms of digital data a 0 or a 1.

Bandwidth
The amount of data that can be transmitted in a fixed amount of time. For digital devices, the bandwidth is usually expressed in bits per second or bytes per second. For analog devices, the bandwidth is expressed in cycles per second, or Hertz (Hz).

Broadcast
When data is sent simultaneously to all stations on a network.

Buffer
Space allocated on a system's Random Access Memory (RAM) where data is stored temporarily until it is transferred to another part of the system. In streaming applications, buffers store video or audio data until there is enough information for the stream to be composed.

Bitrate
The speed at which data travels from one place to another on a computer network, such as the Internet.

Compression
The reduction in the size of data in order to save space or transmission time. Compression is performed by a program, which uses an algorithm or formula to determine how best to compress and decompress the data.

Digital Video
Digital video is the key to content when streaming media. Digital video is an alternative way of storing or distributing video. Digital video is usually converted from an analog video source. A digital video signal is represented in '1's and '0's, whereas an analog video signal is represented by a fluctuating voltage signal that is stored on magnetic tape. This difference is similar to the difference between analog audio and digital audio.

Encoder
A hardware or software application used to compress audio and video signals for the purposes of streaming.

HTML
Hypertext Mark-up Language. The formatting code used to create web pages.

HTTP
Hypertext Transfer Protocol. The protocol used to distribute web pages. Some streaming media productions are also sent to end-users via HTTP. (Kilobits per second) - The rate at which data is sent over a communication line. The typical household modem runs at 56.6 kpbs.

Mbps
(Millions of bits per second) it is a measure of bandwidth. A unit of information transfer rate. While an Ethernet connection can run at 10 Mbps the average household modem still runs at 56.6 kbps (kilobits per second)

MP3
MP3 is the MPEG audio layer 3 standard. Layer 3 is one of three coding schemes (layer 1, layer 2 and layer 3) for the compression of audio signals defined by the MPEG committee. Layer 3 uses perceptual audio coding and psychoacoustics compression to remove the redundant parts of a sound signal. It also adds a MDCT (Modified Discrete Cosine Transform) that implements a filter bank, increasing the frequency resolution 18 times higher than that of MPEG audio layer 2.

Metafile
A file that minimally contains a URL that points a media player toward a streaming media source. Generally served using HTTP. May be a static file or generated dynamically. Commonly use the filename suffixes RAM (RealNetworks), ASX, WMX (Windows Media), and MOV (QuickTime).

Narrowband
Used to describe a connection over a computer network, which supports a relatively low bitrate. Also sometimes used to describe content optimised for such connections.

RealAudio
Describes a file format for audio-only streaming media technology released by RealNetworks, a leading streaming media platform vendor.

RealMedia
Brand name describing file formats, server software, player software, and protocols used by streaming media systems from RealNetworks, a leading streaming media platform vendor.

RealVideo
Describes a file format for audio/video media released by RealNetworks, a leading streaming media platform vendor.

Streaming Media
Streaming media technology enables the real time or on demand distribution of audio, video and multimedia on the Internet. Streaming media is the simultaneous transfer of digital media (video, voice and data) so that it is received as a continuous real-time stream. Streamed data is transmitted by a server application and received and displayed in real-time by client applications. These applications can start displaying video or playing back audio as soon as enough data has been received and stored in the receiving station's buffer. A streamed file is simultaneously downloaded and viewed, but leaves behind no physical file on the viewer's machine.

Video Compression
The process through which a complete video file is reduced in size. Video Compression algorithms take advantage of the fact that there is minimal difference from "one" frame to the next. The first frame is encoded and then the sequence of differences between frames. This is also known as "inter-frame" coding or "3D coding".

Video Service Provider (VSP)
- Video Service Providers are analogous to Internet Service Providers (ISPs) except that they specialize in providing multimedia storage and streaming services for Internet sites. In this scenario, when a company offers streaming applications on their Internet site, clicking on the video or multimedia file will transparently connect users to the Video Service Provider that stores and streams the content.

Video On Demand
Describes video content that may be viewed by the end-user from beginning to end, at any time.

Windows Media
The streaming media platform released by Microsoft.

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