Development And Realization Of Embedded Video Driver Based On V4L2

In recent years, the flourishing of embedded systems has diversified the function and usage of electronic devices. If we want the embedded systems to migrate to electronic devices quickly, the device driver must be provided timely. On the other hand, in the research of the embedded systems, probably because there is no corresponding device driver in the OS, it requires more time and efforts to develop the device driver. The general development of the driver is more important when the emergence of new equipment standards. So, writing the kernel driver can deepen the understanding of the driving process and develop better application programs in accordance with the actual need. Meanwhile, the analysis and improvement of driver and transplantation in the embedded systems have important practical significance and scientific value.This thesis has designed and implemented the video device driver for V4L2. It also introduced the whole process of the development of embedded Linux, which includes establishment of hardware and software platform, construction of the cross-compiling environment, as well as the transplantation of the embedded operating system. On this basis, we set up a simple network video monitoring system.The work this paper completed is as follows:(1) Building hardware and software environment by the use of TQ2440 development board and embedded Linux system; establishing the cross tool chain according to the needs of the cross-compiling environment.(2) On the basis of knowing well about the theory of system migration, we have realized the transplantation operation of the BootLoader, Linux kernel and root file system at the TQ2440 development board.(3) The paper gives the design plan of the video driver, compiles and develops the driver program of the USB camera, and also loads it into the embedded Linux system based on the video standard of the V4L2. (4) It is using the dual-frame cache technology to design and realize the code during the process of video transmission that speeds up the image collecting, improves the system performance.(5) Using the JPEG format on collecting images for coding and decoding, thus having achieved fast transmission and processing of data.(6) The paper studies the development process of the embedded application program, sets up a simple network video monitoring system and gives test results of the access to the embedded video terminal.