| Nowdays,the projector plays an increasingly important role in people’s daily life and work.But at this stage,almost all of projectors in use are basically required by the wiring construction and also limited by wiring connection when projecting.In order to overcome the inconvenience of traditional projectors in use,at the same time,in order to make full use of existing resources through modifying original wired projectors,this paper designed and implemented a wireless projection system which was based on embedded Linux operating system,ARM11 processor S3C6410,video encoding and decoding technique of H.264 and display technique using SDL.Firstly,the paper determined the system overall design scheme according to the functional requirements of the wireless projection system,and the whole system consisted of three parts,including the embedded hardware,embedded operating system and application programs.Secondly,the paper finished the selection and construction of hardware platform.The FILIN OK6410 development board with the micro controller S3C6410 was selected to be the implemention platform of hardware system,and the LCD to VGA and SDIO-WiFi were selected to be the auxiliary modules of this system.Based on the design of hardware,the embedded system of Linux was built,including the Linux kernel transplantation,the construction of root file system and device driver porting.Then,the paper comprehensively studied the H.264 video coding algorithm and its optimizations including the working principle of H.264 coder and decoder,integer DCT-algorithm,intra prediction,inter prediction and entropy coding algorithm.Thirdly,combined with the functional requirements and the software design scheme,the software has been completed,which can be divided into PC software and ARM software.The PC software is a Win32 program under Windows operating system,which is consisted of software functions such as implementation of screen capture,H.264 video encoding,its parameter settings and so on.The ARM software object code platform selected common PC that was installed with Ubuntu11.10 operating system,and the paper completed each software functions of ARM by means of cross-compiling,including H.264 video decoding,SDL video playback,and the design of communication software of the whole system.Finally,the paper has completed implementation of software and hardware integration of the wireless projection system.The system unit testing and overall testing indicated that the wireless projection system realized by the paper could work successfully.The design and implementation of the wireless projection system has reached the expected purpose,which is full of highly practical value.It is meaningful and valuable innovation of the traditional projection product. |
