The Design Of High-definition Video Encoding And Transmission System Based On DM365

Network cameras are changing our lives as they're advanced, real-time, reliable, easy to operate, easy to expand. But the current network videos are mainly standard definition (SD) videos, the image details can not be effectively resolved, and the network transport stream formats are very limited, therefore, the application of high-definition (HD) video is at full cock. However, the following problems still exist in the currently HD video network transmission technologies: 1) Large amount of data compression requires high-performance devices; 2) Huge network environment differences need streams to adapt to different bandwidths and network user requirements; 3) HD analog video sources is quite expensive. However, with the development of embedded system technology, coding standard technology and network technology, the popularity of the HD system becomes available.In order to meet the needs of HD video network transmission, high-performance DSP technology is used to realize the real-time video 1080i as well as 720p compression and transmission system in this paper. The main tasks are: 1) For video acquisition module, a deep study of the basic principles of the CMOS camera and video capture, video processing front end (VPFE) for RGB real-time data collection methods and the video acquisition method of the Linux V4L2 is made; 2) To meet the demand of video coding and compression, a thorough investigation of video codec algorithms principles as well as the advantages and disadvantages is taken for the H.264, MPEG4; 3) Protocols for embedded Web Server such as HTTP, CGI and so on are studies to cater for different network needs; while RTP/RTC, RTSP and other protocols used for media streaming are also studies deeply in this paper; 4) The design of hardware system is completed, and the collected data is processed and coded by DM365 ISP and co-processors respectively when modular design is carried on; 5) Based on the Linux operating system, AV SERVER architecture is adopted to compile separate multi-threaded application core code modules.This system realizes the 720p30fps@H264, 352i15fps@H264, CIF15fps@JPEG three-way stream transmission, H264, MPEG4 and JPEG storage, and FTP functions. It can complete videos compression and transmission with a variety of streams and different resolution. In addition, it improves the function of the system through real-time controlling and operating by CGI. Besides, the overall system power consumption is less than 3W, video streaming is up to 4000kbps.