2002 - cesnet

Figure 6.4: Example of broadcast from peregrine falcon’s nesting6.4.2 Live Broadcasting of Public-Service MediaThe collaboration with Czech Radio, we continued predominantly in the areaof audiostreaming. The objective was to design and implement a system whichwould enable non-stop live broadcasting of Czech Radio stations via the Internet,at a very high quality.Czech Radio runs a live Internet broadcast of its largest stations, with the useof Real Audio and Windows Media technologies, at speeds of 10–32 kbps. Thisspeed does not enable broadcasting at high sound quality. During 2002, the CES-NET association and Czech Radio concluded an agreement concerning theirmutual collaboration in the development of an experimental system which willenable live broadcasting of Czech Radio stations via the Internet at a high quality.After the evaluation of the required objectives, we decided to implement theentire system on the basis of the technologies for audio signal broadcasting inthe MPEG compression formats (MP3) and Ogg, with the bandwidth of 128 kbps.For these purposes, we made use of the Icecast2 application server and theDarkIce coder. Both applications are developed as open source projects so theyare free to use. The resulting audio signal suffers from a certain loss due to thecompression algorithm; however, it is almost impossible to recognise betweenthis signal and the original one.At present, the entire system is running on two servers located within thepremises of the CESNET association. The encoding server (configuration: DELLPowerEdge 2600) serves as a stream producer. There are tuners connectedto the sound card inputs, tuned to the broadcasting of the following stations:High-speed National Research Network and its New Applications 200291