Heterogeneous Agricultural Video Service Systems Integration Based On User-defined Protocol

With the rapid development of computer, network communication and multimediatechnology, many agricultural areas have constructed remote video service systems to providetraining and expert advisory services. Due to the lack of unified planning and standards, videoservice systems in different areas are constructed in specific areas and significant differencesare presented. Even if some of them have the same structure, specific modules and controlprotocols are always heterogeneous. To solve the problems of the service range limitationcaused by the disabled interconnection between heterogeneous agricultural video servicesystems distributed in different areas, this dissertation has to do some research on the topicsmentioned above. It is specialized for integration and demonstration of the key technology ofan agricultural and rural information service platform. Main contents and conclusions are asfollows:(1) After researching the current constructed video service systems, the standard andtechnical specifications, system architecture and audio and video coding technologies of themare analyzed. This dissertation provides a system interconnection solution which is easy toimplement, less cost and easy to be accepted by different heterogeneous systems. Then videoservice control proxy is introduced, and those heterogeneous systems only need to add aproxy to communicate with the video service controller to achieve protocol translation andtranslate video and audio stream to streaming format. Because unified protocol is followed bythe video service controller proxies, they can shield differences in heterogeneous systems.(2) Heterogeneous systems interconnection protocol has been proposed based on thesolution above. Firstly, the protocol package structure and interaction order have beendesigned. Then the protocol has been translated into program with protobuf, which is aprotocol tool provided by Google. Finally the security mechanism strategy has been analyzed.(3) A distributed video service system based on the protocol mentioned above has beenconstructed to verify the interconnection solutions’ feasibility of the heterogeneous systems.Firstly, the video service control server has been constructed based on the Apache Minaframework, which mainly contains functions as follows: member verifying, member speakingcontrolling, and management of speaking queues. Secondly, video service terminal softwarehas been designed with C++. The functions include audio and video capturing, coding and playing, communicating with the control server, providing E-board to assist communication.Then a JAVAEE-based video service platform has been built to manage the service sites,training plans, users and resources, and support online live video playing and playback.Finally the heterogeneous systems interconnection solution has been verified by testing theinterconnection between homogeneous and heterogeneous systems. Tests show that theheterogeneous systems interconnection solutions do have feasibility.