RTSP를 이용한 임베디드 하드웨어 기반 동시 방송 시스템개발

Increasing occurrence of natural disasters lead to changes in our lifestyle in various ways. This paper presents a simultaneous audio broadcasting system based on an embedded platform that can be used in disaster warning applications. The system consist of a server that streams audio signals to different clients connected within a network. The actual media delivery is implemented using real-time protocol (RTP) stream concept encapsulated into real-time streaming protocol (RTSP) to control media transmission and ensure transmission of data between each component. We develop embedded platforms, with attached hardware audio codec, as streaming server and clients. Device driver using Advanced Linux Sound Architecture (ALSA) is developed to operate the hardware codecs and convert analog audio signals to digital signals and vice versa. Open source libraries are implemented in the server and clients to support data exchange using RTSP and RTP. Transmission loss and delay were solved in the embedded environment using μ-law. Experiments are performed in unicast and multicast streaming to validate the practicality of the developed system