Research And Implementation Of Audio And Video Transmission System Based On RTSP

The home service robot has gradually developed from providing single family labor service to provide multi-level information services for domestic users, including video surveillance, multi sensor environment monitoring and so on. The audio and video transmission system implemented in the home service robot needs to consider the problem of audio and video synchronization, as well as multi client for home users. The purpose of this paper is to design and implement the audio and video transmission subsystem based on the home service robot, and the audio and video synchronization technology in the system. The main work includes the following aspects:(1) Firstly, this paper introduced the development trend of home service robot, the research status of audio and video synchronization technology and RTSP (real time streaming protocol) protocol, the audio and video decoding technology in Android system. The media technology involved in the paper, such as progressive download and streaming real-time transmission mode, are analyzed. Then we focus on the real-time streaming transmission protocol.(2) The problem of audio and video synchronization in the audio and video transmission system is studied. On the basis of a large number of literature and analysis of the reasons for the loss of synchronization of audio and video, an adaptive audio and video synchronization scheme based on network delay detection is proposed. The scheme combined with the fluctuation of network delay and the network congestion control mechanism of RTCP (realtime transport control protocol) protocol to complete the judge of the network status, and choose synchronization scheme in different status of network. The solution based on synchronous data node and time stamp is used in the high latency network. Then we set up the experimental platform to carry out the simulation experiment. The experimental results show that it can achieve a good effect of audio and video synchronization.(3) The Design and implementation of audio and video streaming media transmission system. In the server side, we have analyzed the source code of Live555 project, and focused on the working principle of streaming media server. We have updated this project for some performance problems and functional defects, and improved these performance issues and expanded its functionality as a streaming media server.In the client side, we used the Android platform as the receiver of the audio and video transmission system, and then deeply introduced the play of audio and video on the Android platform. Then we transplanted FFMPEG and SDL to Android platform, and developed a multimedia player under the Android platform, and solved the existing problem of supporting a limited format of multimedia file format and audio and video coding format in Android platform. According to these, we proposed an algorithm of audio and video synchronization based on Android platform and realized the synchronous playback of audio and video. Moreover, the proposed synchronization algorithm in this paper, has a very good cross platform characteristics and can be easily ported to other platforms.(4) Finally, we introduced the software and hardware environment for running the whole audio and video transmission system and did some tests after the completion of the system deployment. Test results show that the system can satisfy the requirement of audio and video transmission, and has better effect in synchronization of audio and video.