基于达芬奇平台的公交车载视频系统研究与设计

发布时间：2018-05-01 00:15

本文选题：DM6446 + 嵌入式系统　；参考：《浙江工业大学》2012年硕士论文

【摘要】：公交车载移动电视作为一种移动多媒体已经成为人们获取信息的方式之一。由于其受众规模庞大和公交车载电视本身平台的特殊性，可以预见其具有非常大的市场价值和研究价值。目前我国大城市都采用基于电视发射塔进行车载电视节目播放的方式，但是此种方案成本极高，令数量众多又有迫切需要的中小城市望而却步。而目前嵌入式系统技术和WIFI等高速无线传输技术的快速发展为解决这一问题提供了可能性。本课题采用基于TI公司高性能达芬奇DM6446ARM+DSP双核高性能处理器搭载嵌入式Linux操作系统，通过WIFI技术进行视频节目更新并且存储到SD卡中方案来设计嵌入式车载视频移动终端。本文从车载视频信息的存储可靠性、车载视频多路播放和视频镂空叠加算法三个方面进行系统性的研究。本文的主要工作和取得的成果如下： 1、本文首先阐述了课题的背景与研究意义，随后分析了国内外的研究现状，提出了本课题的研究目标与内容。 2、系统突然断电造成SD卡中的FAT文件系统出现异常，从而影响整个系统稳定性。本课题采用制作嵌入式FAT文件系统修复工具来维护系统稳定性。采用树状的文件遍历算法来进行文件遍历，依据FAT表分段读取和位簇标记法最大限度的减少修复工具的内存使用，最终将发生异常的次数和数据损失情况反馈给系统。 3、传统的车载电视大部分都只是具有视频播放功能且播放画面单一，不具有多路视频播放功能。本课题基于嵌入式Linux环境下的共享内存、进程间通讯和多线程等技术，通过达芬奇技术Codec Engine机制实现多路视频的并行解码，实现多路视频播放效果。 4、目前广告视频叠加功能的实现都是基于服务器端或PC的，都不具有镂空的效果。本课题依据TI的xDAIS/xDM算法标准通过CCS3.3工具将视频镂空叠加算法进行打包封装，并且验证算法的有效性和正确性。该算法经过程序级、DMA与Cache、编译器和线性汇编优化，，使算法的执行效率得到了很大的提高。 5、最后对全文进行总结并提出需要进一步研究的问题。
[Abstract]:As a kind of mobile multimedia, bus-borne mobile TV has become one of the ways for people to obtain information. Because of its huge audience and the particularity of the platform of bus TV, it can be predicted that it has great market value and research value. At present, the large cities of our country adopt the way of carrying TV programs broadcast based on the TV transmitting tower, but the cost of this scheme is very high, which makes a large number of small and medium-sized cities which are in urgent need to be prohibitive. The rapid development of embedded system technology and high-speed wireless transmission technology such as WIFI provides the possibility to solve this problem. Based on the high performance Da Vinci DM6446ARM DSP dual-core high performance processor of TI company, the embedded Linux operating system is used in this paper. The video program is updated by WIFI technology and stored in SD card to design the embedded video mobile terminal. This paper systematically studies the storage reliability of vehicle video information, multi-channel video playback and video hollowed-out superposition algorithm. The main work and results of this paper are as follows: 1. Firstly, the background and significance of the research are described, and then the present research situation at home and abroad is analyzed, and the research objectives and contents are put forward. 2. The sudden power outage of the system results in abnormal FAT file system in SD card, which affects the stability of the whole system. This topic uses the embedded FAT file system repair tool to maintain the system stability. The tree-like file traversal algorithm is used to traverse the files. According to the FAT table segment reading and the bit cluster marking method the memory usage of the repair tool is minimized. Finally the frequency of abnormal occurrence and the data loss are fed back to the system. 3. Most of the traditional on-board TV only have the function of playing video and playing a single picture, and do not have the function of multi-channel video playback. Based on shared memory, inter-process communication and multi-thread technology in embedded Linux environment, the parallel decoding of multi-channel video is realized through the Codec Engine mechanism of Da Vinci technology, and the effect of multi-channel video playback is realized. 4. At present, the realization of advertising video superposition is based on server or PC, without hollowed-out effect. In this paper, according to TI's xDAIS/xDM algorithm standard, the video hollowed-out superposition algorithm is packaged and encapsulated by CCS3.3 tool, and the validity and correctness of the algorithm are verified. The algorithm is optimized by program level DMA, Cache, compiler and linear assembly, and the efficiency of the algorithm is greatly improved. Finally, the paper summarizes the full text and puts forward the problems that need further study.
【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TN949.2;TP391.41

【参考文献】