Design And Implementation Of The Mobile Video-on-Demand System Based On RTP

With the development of mobile communication technology and the improvement of performance of mobile terminals, it is possible that mobile communication network provides streaming media services. Therefore, streaming media transmission based on mobile device is a very interesting research direction. This paper discusses design and implementation of mobile video-on-demand system based on RTP, and makes an intensive study of key technologies which include synchronization strategy of audio and video, video image amplification, video transmission and data packets encapsulation of video transmission.Based on the real project named "Mobile video-on-demand system" of one company in Zhongshan city, this paper combines the streaming media technology with mobile devices, so people can have high quality video-on-demand service through mobile networks.This paper studies correlation technique of the streaming media transmission. It introduces a variety of audio and video encoding formats, and analyzes their characteristics and applications; Make an intensive study of TCP protocol, UDP protocol and RTP/RTCP protocol, compare the advantages and disadvantages among them, and choose the best streaming media transmission protocol; Do the research of video encoding technology of H.264, analyze the bit stream stucture of H.264.According to characteristics of mobile networks and streaming media transmission, this paper proposes the overall design of mobile video-on-demand system. Then, this paper does the detailed design and implementation according to the overall design of this system, the entire system is divided into several modules which include the server module, the network transmission module and the client module. Mobile streaming media client can run on mobile communication network, and the server runs on the public network. This paper uses the open source library JRTPLIB to implement RTP/RTCP protocols, and makes use of the double-buffer queue of audio and video to improve the performance of the server and the client. Through the use of the NAT technology, it can realize the communication between PC and the mobile internal network; To improve the transmission efficiency, streaming media data on the server is encapsulated into the corresponding RTP packet; Streaming media data is decoded on the client, and this paper uses the audio and video Synchronization technology based on the audio clock, and achieve the consistent playback of audio and video; This system can magnify the video image appropriately on the various mobiles of different resolution ratio while maintaining clarity of the video.Finally, this paper introduces the system testing and application. In Symbian platform, test streaming media client in the GPRS and EDGE network environment, implement smooth playback of the streaming media in the mobile communication network, and achieve the design requirements.