Media Streaming

More recently streaming was introduced as an effective alternative to download, particularly for larger files containing video, and provided a means to transfer content in smaller sizes and view whilst delivery continued.

Streaming media has been around for many years in the Internet arena and has given many Internet Service Providers and Application Service Providers the opportunity to generate new revenue and foster customer loyalty. Recently multimedia streaming has expanded its reach to many wider applications.

Streaming Process
The streaming process can be broken into four main elements: acquisition, preparation, distribution and playback.

Acquisition: first acquires the media from its source such as from a camera, microphone, storage device (e.g. DVD) or a broadcast input and transfers it to a storage device ready for preparation or in some cases the source is compressed immediately as it arrives.

Preparation: a variety of preprocessing filters can be applied to the source content which enhances the quality of the final encoded output. A coding process is then applied to convert and compresses the information into a format suitable for transmission and rendering on the media player. Preparation can also include editing and storing or in some cases for live streaming transmitting directly to the distribution server.

Content distribution: process sets up communication to the media player from the streaming server. The server responds to requests from the clients and can serve many clients simultaneously.

Content playback: process then decompresses and plays back the file. As soon as the player starts receiving the file it starts to play it with little or no delay by utilising the output devices of the users device such as the device screen and speakers.

Multiple Streaming Formats
Many proprietary and open standard formats exist for streaming which address all or some of the functions of encoding, file format, streaming and decoding of video, audio, & still images. A stream encoded for one format is often not accessible through the player of a different format.

The most popular proprietary formats include Real, Windows Media, QuickTime and PacketVideo. Open standards for audio such as MP3 & AAC and for video such as H.261, H.263, MJPEG, MPEG1, MPEG2 and MPEG4.

It is likely that multiple formats will coexist for some time although there has been some small but significant movement towards MPEG4 as a common industry standard. Nonetheless supporting infrastructure will be required to accommodate multiple streaming formats for the foreseeable future.

Streaming Applications
Streaming is best used for distributing applications containing video and high quality audio, and live broadcasts, and has been adopted by many industries such as sport, music, films, education, tourism, commerce, and medicine.

Corporate and enterprise companies have adopted streaming for internal corporate video briefings, circulating executive communications, online training and rich media advertising.

More recently 3rd Generation mobile companies have launched streaming services applications such as music, sport clips, live events, ringtones, health & fitness videos, healthcare and telemedicine, and multimedia messaging retrieval.

A rapidly emerging streaming application is in the Broadcast Television industry for high quality (MPEG-2) IPTV and Video on Demand pay-per-view over cable, DSL and satellite infrastructures.

Many other examples of streaming applications exists across many markets such as: schools & universities courseware being delivered using multicast lectures; sport and music industries taking advantage of the ability to broadcast live games and concerts; hotels have adopted streaming as an alterative to downloading films to rooms; CCTV camera video can be streamed to PDAs or remote terminals for security & monitoring; and long duration live events such as Parliament can be multicast to wide audiences.

The Streaming System
The typical streaming system contains three major components: the encoder, the streamer and the client player (or decoder). The system may reside within a wider content management system that is responsible for the end to end process of capture through to playback.

A range of IP protocols are used by the streaming system including RTP (Real Time Protocol) for the real time transport of the media from the streaming server to the player/decoder and SDP (Session Description Protocol) for the session description.

RTSP (Real Time Streaming Protocol) is a streaming specific presentation control protocol between the streaming server and the player/decoder, designed to address the needs for efficient delivery of streamed multimedia over IP networks. The protocol includes messages called Methods (e.g. OPTIONS, DESCRIBE, ANNOUNCE, SETUP, PLAY, PAUSE, TEARDOWN) and Responses (e.g. 1xx: Informational, 2xx: Success, 3xx: Redirection, 4xx: Client Error, 5xx: Server Error).

Proprietary streaming systems can use either their own proprietary protocols or utilise open standard protocols.

Future of Steaming
With the increasing deployment of IP infrastructure and communications, streaming is becoming more popular as a way of transmitting audio-visual information over wireline and wireless networks.

The technology is still evolving, the performance of codecs is developing at a rapid pace, and the emergence of broadband core and access has radically improved the streaming experience.

Overall, businesses find that streaming media offers great opportunities to reduce cost in current business models and generate revenue from new modes of operation.

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