Design And Implementation Of A Project About Video Recording And Broadcasting System Based On DIRECTSHOW Architecture

The classroom equipped with record and broadcast devices is the outcome of streaming-media technology development and teaching pattern innovation, which meets the needs of long-distance education, exquisite course and teaching evaluation. This type of classroom is a whole solution to record the process of teaching and course's resource as video, then to broadcast them over networking. It consists of devices controller sub-system, intelligent camera sub-system, video record and broadcast sub-system, courses management sub-system and so on. Furthermore, the video record and broadcast sub-system is the kernel of the whole system, which mainly deal with collecting, process, save and broadcast video and audio data.Directshow is a multimedia application program interface (API) based on COM, which proposes a new process model for multimedia data. Aiming at the needs of advanced classroom for recording and replaying online, the thesis proposes an approach to design and implementation of recording and broadcasting video based on Directshow.We firstly introduce the components of this classroom, and then analyze the actuality and the popular technologies. We got some breaking results, such as record/replay live with dual code streams, and mixture technology for multi-access video.The proposed solution is based on Directshow and related video processing technologies. Therefore, we introduce the system architecture of Directshow, and Filter technology. The principles of compiling video, the main stream technologies of video and audio decode are dilated. The video recording and broadcasting sub-system is composed of encoding server and broadcasting server. The former can collect, process, encode, transmit and store video data, and the latter can long-distance broadcast the video live by configuring Media Service correctly.The implementation of the whole system mainly includes the development of Filter components, Filter graphics and the mixture technology, especially, the implementation of the three key Filter components. At last, the implementation of encoding server and broadcasting server is introduced, which include constructing Filter Graph, designing control interface and the protocol of communication.To verify the performance and capability of the system, the testing solution is proposed and implemented. Finally, we analyze the processing and results of the testing, conclude its advantages and disadvantages, and forecast its marketing foreground further.The key components proposed in this paper have been applied in several multimedia classrooms, some of them have been granted patent right.