Research And Design Of Bus Video System Based On Davanci Platform

As a kind of mobile multimedia, bus mobile TV has become one of the ways that peopleaccess information. Due to its large number of audience and special platform, the bus mobile TVcould be predicted with large market and research value. The large cities of our country, the busTV play the video programs based on the TV tower, but such equipment cost very large. So alarge number of small and middle cities can not use this module because of the cost. At present,the rapid development of embedded system technology and WIFI wireless high-speedtransmission technology offers the possibility to solve this problem.Based on TI’s high performance DaVinci DM6446ARM+DSP dual-core chip, runningembedded Linux operating system, downloading video programs by WIFI and storing the videoprograms in SD card, this model was used to design the embedded vehicle mobile video terminaldevice. This article will have a deep systematic study on the storage reliability of vehicle videoprogram, multi-window video play and video hollow overlay algorithm. The main work andcontribution of this paper are listed as below:Firstly, the significance of this thesis is presented together with a brief summary of thepresent research status.Secondly, a sudden power-off may cause file system abnormalities to FAT file system of SDcard and affect the system stability. This topic used the embedded FAT file system repair tool tomaintain system stability. In the projcect scanning files based on tree structure algorithm, FATtables segment reading and cluster markers were adopted to improve the memory efficiency inthe embedded FAT repair tool. Eventually the feedback on abnormal frequency and data losswould report to the system.Thirdly, most of the traditional vachile mobile TV just had video play function and did nothave multi-window video play function. In this paper based on TI’s high performance ARM+ DSP dual-core processors DM6446, shared memory, inter-process communication andmulti-threading technology in embedded Linux environment were used to implement the paralleldecoding and mutil-window display through Codec Engine mechanisms of DaVinci technology.Fourthly, advertisement video overlay function was implemented by server-side or PC anddid not have hollow effect. In this topic video hollow overlay algorithm was packaged byCCS3.3tool based on TI’s xDAIS/xDM algorithm standard. The validity and accuracy of thealgorithm were verified. The algorithm implementation efficiency had been greatly improved bythe optimization of the program level, DMA and Cache, compiler and linear assemble.Lastly, the whole thesis is summarized briefly and some suggestions are given to helpfurther improvement of the whole system.