Design Of Hardware Circuit And Device Drivers For Audio-Video Acquisition And Transmission System

In this thesis,a kind of circuit about audio and video capture transmission system as well as the device drivers for related custom interfaces are designed and implemented based on the project requirements.The core chips used in this system are DM365 and FPGA.Specifically,the DM365 has strong capability of audio and video codec,and the FPGA has convenient circuit customization capability.Both of these advantages are fully utilized in this design to achieve the project requirements.The main contents of this thesis are as follows:(1)The hardware of audio and video capture transmission system is designed and implemented,which mainly includes the audio and video acquisition circuit based on DM365,and the data buffer and transmission interface circuit based on FPGA.The system board is designed as a pluggable dual-board structure with a separate digital and analog board,which facilitates post-maintenance and upgrades while reducing the size of the board.The system supports CVBS and S-Video analog video signal acquisition and a dual-channel audio acquisition.(2)The design and implementation of the underlying hardware driver based on the custom interface circuit mainly includes the EMIF interface driver and the SPI interface driver.DM365 exchanges data with custom memory in FPGA through these two drivers.The DM365 reads the parameters required for audio and video processing from the configuration memory through the EMIF interface driver,and writes the processed audio and video data to the FIFO memory which is to be read by the host computer.The DM365 obtains time information from time buffer by SPI interface driver,and calibrates system time with this time information.At the end of this thesis,the modular test and the system functional test of the audio and video capture transmission system are made.The test results show that the system realizes the functions of real-time audio and video signal acquisition,processing and transmission,which meets the design requirements.