The Embedded Linux Platform Audio And Video Transmission Research And Implementation Under The Ad Hoc Environment

With the development of wireless network technology, the mobile Ad hoc network gradually comes into our sight as an innovative network technology, Ad hoc network has such characteristics as no center, self-organized, multi-hop routing, dynamic topology. Its applications are very extensive which range from the military battlefield, emergency rescue and disaster relief, to the sensor networks. The rapid development of the embedded technology makes the embedded terminal smaller, more convenient to use, more powerful, more applications. Under the Ad hoc wireless network environment, the realization of audio and video data transmission on the embedded system has sufficient research value and practical value, will also have a wider range of needs and applications.This paper introduces the research and implementation of an audio and video transmission scheme based on the embedded Linux platform under the Ad hoc environment. Firstly the paper analyzes the features and applications of Ad hoc network, introduces the characteristics and functions of embedded microprocessor and operating system in embedded Linux platform, and then introduces the hardware platform of the embedded terminal in the subject. Followed by a detailed analysis of the features of Internet Phone VoIP technology, Session Initiation Protocol SIP and Real-time Transport Protocol RTP used in Internet Phone services. Then the paper introduces a concrete realization of audio transmission, including the analysis of Internet Phone software Linphone, and then introduces the cross compiler and transplantation and programming work of Linphone and its dependent libraries. Next explains the functions and working process of ffserver steaming media server, and the realization of video transmission scheme. Then the paper analyzes the video equipment kernel driver V4L2and multimedia development kit SDL also audio and video codec library FFmpeg, and their cross compiler and transplantation and programming work. At last, we take some tests of real-time.voice communication and real-time video data collection and transmission and display in the actual Ad hoc network scene. Modifying and adjusting the software platform according to the results of those tests, and suggesting the further improvement work.