Design And Implementation Of Video Transmission System Based On Davinci Platform

With the development of network technology, embedded technology and image processing technology, video transmission system has been widely used in video surveillance, video conference, and remote education, network broadcast and so on. The original video data is large and people’s requirements for video images’real-time, clarity, fluency are also getting higher and higher, so the design of the transmission system is very important.Compared with the previous standards, the H.264 standard has higher compression ratio and good network adaptability, which makes it a popular standard for video transmission. But it increases the complexity of the algorithm. To achieve the H.264 video data real-time encoding, and complete the transfer task, the requirement of the processor is relatively high. The Da Vinci platform incorporates a DSP core and an ARM core. DSP chip deals specifically with H.264 video compression algorithm; ARM completes video transmission and the control of peripheral equipment.The video transmission system of this thesis is mainly for software design based on DaVinci platform. Firstly, this thesis analyzes the dual-core architecture of the DaVinci chip TMS320DM6446 and the mechanism of Codec Engine for dual core communication. Then, this thesis builds the software development environment on the development board with DM6446 chip, including the installation of the SDK suite, the transplant of U-boot and the kernel, and builds the network file system used in the development process for the test. After that, started the software design, mainly including the following aspects:completed video capture by using Linux video driver interface V4L2, called H.264 algorithm to complete the video encoding through the Engine Codec mechanism; analyzed the bit stream structure of H.264, RTP payload for H.264 video and packetization modes; extracted NALU from the encoding H.264 stream and packaged into the RTP load in different ways, and transplanted the open source JRTP library to complete the task of transmission. Besides, the reliable transmission based on TCP is designed as a download service.Finally, the whole system is tested by using the development environment that built before. VLC multimedia player is used to receive and decode the transmitted video. The video transmission system can run stably and the video picture is clear and smooth. So, the system can meet the expected design requirements.