The Audio Control using TDM(Tree-structural Distributed-terminal Mixing) in the Webcast

This paper describes an efficient audio flow control method in the point of quantitative performance using TDM(Tree-structural Distributed-terminal Mixing), compared to existing P2P(Peer To Peer) method. In comparison with existing P2P method, using central mixing and distributed terminal mixing method, we achieved advance at the point of global network usage and each terminal's CPU load, and additionally we expect more session, more terminal can be served by same amount of network bandwidth and computers. By using P2P method in audio communication, speaker and listener must connect to each other. So it has the critical defect that as the participants grows more and more, the network bandwidth usage, each terminal's CPU load will grows rapidly. So the number of participants in same session will be extremely restricted. In comparison with P2P method, the central mixing method has the great advantage at the points of network usage and terminals CPU load. Regardless of the number of speakers and listeners, all the participants can speak and listen with all other participants by using just one stream's amount of data size and CPU load. But all the network usages and CPU loads of "Audio decompression->Buffering->Mixing->Audio Compression" are concentrated on central server. So the number of sessions and terminals can be participated in one server will be highly restricted. This study solves the problems of server's CPU load and network load by using TDM. The TDM is the method to distribute the overload for gathering, mixing and distributing the audio data according to each terminal’s up/down bandwidth and data processing capability using tree-structure. This method enables many terminals participate in the internet-broadcasting by distributing the overload of server to all the terminals. Keyword: TDM, audio, mixing