| Visual conversational system greatly improves people’s living environment Analog visual conversational system is now widely used,but it’s transmission distance is limited and wiring is complex; Digital visual conversational system is better,it’s transmission distance is far,and the wiring is simple, but the cost is high. A semi-digital visual conversational system is designed in this dissertation, and the software of it’s core component-networking switch is designed mainlyFirstly, Linux operating system is studied in depth and the operating system Linux-2.6.19is transplanted onto the networking switch.Secondly, according to the hardware, video capture module, video display module, audio capture and playback module and serial communication module is designed, and related registers are configured, After debugging, the driver can work well;Then, the TCP/IP protocol, H.264video codec protocol and G711audio codec protocol are studied in depth, RTP protocol is used to complete the network transmission of audio and video signals by programming, TCP and UDP protocol are used to complete the transmission of message and control signals, multi-thread and shared memory are used to improve the quality of audio and video transmission. In this dissertation, the video data in720*576resolution can be transported smoothly, and a database for visit record and message is designed.Finally, many other functions are realized by programming, such as message publish,visit record, system management and product configuration.A management software is designed to manage all the terminal equipments... |
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