Alm-based Video Transmission System Research And Implementation

Real-time video communication technology has important applications in future life such as video conferencing, distance education, video telephony, video on demand and so on. In real-time multimedia communication applications, application layer multicast transmission is one of the critical technologies. The advantages of application layer multicast only need to focus on the client system design for developers, to facilitate promotion implementation and optimization.The thesis introduces a video-based application layer multicast transmission system design. The system is divided into four modules: video information collection module, video information coding block decompression module, video information transmission control module, and video server module. In the structure of the transmission networks, we use a hybrid P2P tree network topology to effectively reduce the pressure on the central server, the network load, the transmission delay and to improve real-time transmission. Server module is responsible for the management of member information meeting and provides support for the establishment and maintenance of multicast trees. Multicast tree construction of the system is based on degree algorithm construction, which not only considers the end point of the bandwidth, but also takes into account the computing power of the node. To improve the efficiency of multicast, it uses two kinds of multi-threaded model with the completion port. Video capture module uses the Video for Windows (VFW) platform. The system uses the H.263 protocol as the video coding standard.The system consists of client-side,server-side video release and server side. Server is consisted of server softwave. Video publishing side collects video data through the camera of the USB interface, then uses H.263 protocol to compress the data, and compressed with a socket to send data; clients receives video through the network real-time publish-side outgoing frame data, then removes image data from the frame, and extract the play. Prototype system has been tested with good availability.