Design And Implementation Of Dynamic OSD For SDI Video

With the rapid development of computer, multimedia and digital communication technology, video technology has been promoted greatly. Video has been raised from an analog signal to a digital signal today. Due to digital television equipment has been widely used, a variety of video interfaces appears in a variety of applications, especially SDI(Serial Digital Interface) interface is the most widely digital video interface in actual use. SDI video typically requires a dedicated video capture card to observe video data. Its feature is expensive and inconvenient in some cases. On Screen Display(OSD) is a kind of technology mixing with graphics or characters information in the signals of video, therefore making graphics or characters appears on TV with the video signals. OSD technology is widely used in video monitoring systems.The capture and display are important part of optics and electrics measure system, with the extensive application of SDI cameras in the environment of shooting range, the capture and display of SDI video is very valuable in applications. The purpose of research is about the design of embedded video processing system, programming with verilog language, achieving the capture of SDI video, the OSD display of SDI video and CVBS video. The main contributions of this dissertation are summarized as follows.First, analysis the requirements of design, discuss the architecture of design, achieve an embedded video processing system based on FPGA, including schematic design, PCB board design and signal integrity analysis. The Spartan-6 xc6slx16 produced by Xilinx is the core of the system, the image processing and logic operation are completed on the FPGA, which can ensure the modular design and real-time. The system has the advantages of standard interface, high stability and high integration. In practical applications, hardware circuit has a reliable performance, meet the design requirement.Then, analysis the format of SDI video, study the characteristics of ITU-R BT.656 standard video signal, programming with Verilog language, achieving the capture of SDI video, output of SDI video and CVBS video on the FPGA, including the module of data broadening, the module of data descrambling, the module of data detection, the module of data scrambling, the module of data adaptation. The problem for video data accepted by the FPGA has not synchronization signal, a method of video sequence detection is presented, achieve the quick detect and extract of the valid video data.Finally, the technology and principle of OSD and screen display are studied, achieve the OSD of SDI video and CVBS video. The problems for ASIC of OSD are more restrictions and inflexibility, with the advantage of high performance and Parallel computing of FPGA, determine the architecture of FPFA and multiplexer ASIC, achieve the design of OSD module on the FAGA; realize the real-time OSD of four CVBS video. Mixed character information when coding SDI video, achieve the OSD of SDI video. By means of double RAM in the FPGA, improve communication between the embedded system and the main system.