The Study And Realization Of AVS Over ISMA Real-Time Packer

AVS is a second generation standard of audio video source coding,developed by China, which also owns part of its intellectual property. The key issue concerned with source coding is compressive coding of great amount of data (original data, source information), so it is also called digital audio-video media coding&decoding technique. Apparently, this technique is the precondition of following techniques such as data transportation, data storage and rendering, therefore it becomes the basic standard of digital media industry. Nowadays, it is becomes more and more popular in broadcasting area and so on. Streming media is a technique which uses audio-video streams via network to transport the media data. It is different from traditional media downloading, in the aspect that it is real-time and continuous. Until now, most streaming media only supports media data, which is coded by MPEG-2, MPEG-4/H.264 standards. Internet Streaming Media Alliance (ISMA) is an organization whose object is to develop open streaming media standard. Recently, AVS and ISMA began to cooperate, yet, ISMA doesn't support AVS standard as well as MPEG-4/H.264. This Paper's purpose is to design a sub system as front end of AVS over ISMA streaming media system, based on ISMA's open framework.Firstly, techniques related to the AVS over ISMA streaming media system was introduced, including AVS coding standard and media communication via IP network. In this part, at the beginning, simple history about audio-video media coding standard was told, followed by introduction about series of MPEG standards. Then, AVS's key techniques and the comparison between AVS, H.264 and MPEG-2 were analyzed. In the IP network transporting part, UDP and TCP was firstly analyzed as transporting layer 2 different protocols to carry the media data, followed by detailed introduction of protocols used in ISMA, such as RTP/RTCP, RTSP/SDP, in the end ISMA standard was simply introduced as whole.Secondly, 2 open source projects, Darwin Streaming Server and MPEG4IP were introduced, which were software platform needed by the AVS over ISMA streaming system. In this part, basic issue of Darwin Streaming Server and its no opened version, QuickTime Streaming Server was firstly told, its open source project original files and programs was analyzed then, in the end, information about MPEG4IP project was simply introduced.In the final part of the paper, detailed design about AVS over ISMA Real Time Packer sub system was given, along with the result of the testing. Firstly, the sub system's function and up level design was offered, followed with the low level design, including the main 2 parts of the program, CAVSRealTimePack andå'Œrtp_transmitter. Then, construction of testing environment was introduced, result of the sub system working in the main system was offered.