Research And Design Of Image Coding And Video Image Overlay Based On OMAP3530

In the information overload today, people receive more than half of the information from the video image. in today's society, Video image is the main information carrier,compare with audio or text, Video image has more information and more intuitive forms of expression. In addition, people more and more adapted to digital life, it's increasingly dependent on embedded devices which as a video image processing system, embedded devices as a mobile terminal can match people's need,like small size, low power requirements. And the most extensive functon of video image processing is the multi-layer video image overlay display, which is overlay the specific character graphic and original video image content.under the premise that have no destroy on the original video image content, you can further enrich the amount of information, Such embedded devices are widely used in security,entertainment, education and other scenarios.However, due to most of the existing embedded solutions rely on a specific dedicated OSD overlay chip or FPGA + DSP dual-core solution, which lead to achieve high cost,poor scalability, does not support superimposed display parameter dynamics Adjustment,and other issues.Regarding the issue above, this paper designed a video image processing system,which based on the Texas Instruments OMAP3530 platform.which integrated ARM and DSP two core as, them can achieve Completely work together. The research in this article mainly contains the following three aspects:(1) achieve the Codec Engine dual-core software architecture. On this basis,Complete The development of multithreaded applicationsmake, which make the full use of the processor performance, and make it true that the ARM and DSP to Completely work together.(2) Base on V4L2 to achieve the Loop queue of Video capture and display, through the OMAP3530 platform modules to achieve overlay display with the specific character graphic, The overlay display process does not need to consider the complexity of the character graphics, and by adding sysfs interface allows system to adjust the parameters to achieve Transparency adjustment when program running the process. Which solve the problem that the image overlay method has poor flexibility and the high cost of development. The final overlay display frame rate is 25fps, the response time less than 20ms, so the human eye will not feel a significant delay frame loss.(3) considering the needs that view video image in remote,so add H.264 video encoding and network transmission in this system. Through porting open source X264,and eventually packaged as a encoder of OMAP3530 platform. The H.264 bit stream generated by the encoder, After the RTP protocol packet transmission, in finally,Real-time decoding of H264 stream in the remote PC, it can match the desired goal.Finally, it is proved that the system achieves the expected goal, but there is still a lot of room for optimization. This paper summarizes the work in the last chapter, and prospects the future research direction.