lunes, 3 de diciembre de 2007

Video & Audio Streaming Concepts

Product : Linux.
Part involved : Streaming Server facilities.
Summary : Clears the way how this technology works.
Scenario : It is part of a free training program taught by COS-PERU.
Company : Open Source Center of Peru (COS-PERU).
Reference date : December 2007.

There are several services such as : radio and tv looking the way to change the broadcast of its signal information and opens the way to access them from internet selecting web browser since your computer. That is integration of Radio&Tv using ip technology.

Radio & TV have use the same requirements to build it and these ones are :

1.- Spread Server
2.- Broadcast Client (Life)
3.- Bandwidth assigned

The techniques used to transmit audio and data (video) is named "streaming". Then the Spread Server (1) managements and emits the streaming signal to www. About the quantity of simultaneous connections supported is called "concurrence" and can be calculated by how do you spend the concurrence resource of Spread Server. Then, next, we find a few samples of needs required for every type of broadcast.

Audio 24Kbps for every user connected
Video 100Kbps for every user connected

Buffer of the Spread Server.- Initially this parameter is considered to program and save space to concurrence concept, check next example :

- If my computer (1.-) has 1G RAM conifigured with 8K Buffer RAM, how many users can be attended ?

Remember that 1G= 1024K, then 1024/8= 128 users or concurrence top value.
The widthband (3.-) used by these concurrence connections then is calculated such as follow for :

Audio = 24 x 128 users = 3,072Kbps
Video = 100x 128 users = 12,800 Kbps
At this point, It's clear how many bandwidth will be used or How can I adjust this resource according to the available of bandwidth of my provider (ISP).

Related to the software used by Spread Server (1.-), we find next software free application to fullfill with this purpose : ShoutCast, IceCast, StreamCast, while these applications assigned carpets into server to every audio and video files to share and save information.

The Broadcast Client (2.-) converts the analog signal into digital signal through video capturer card (video broadcast case) while the client computer (user placed in office or home connected through www) needs to support multimedia basically since the applications WinAmp, Real Player, Windows Media to connect to (2.-).

There is a video example attached to show (2.-) under main title "YouTube Videos hosted by German Medina" at the right bottom of this page and select title "Video Streaming Concepts" for more information.