【作者】 李英伦；

【导师】 杨宗凯；

【作者基本信息】 华中科技大学 ， 通信与信息系统， 2005， 硕士

【摘要】 随着计算机进入后PC时代、多媒体技术和无线通信技术的发展,融合通信、计算和多媒体功能的各类多媒体终端(如PDA)应用正在成为开发应用的新亮点,视频则是这类应用中不可缺少的重要组成部分。多媒体终端,作为嵌入式系统,大多数应用场合是对速度、功耗、体积有严格要求的车载、移动通信、手持式设备等,那么如何设计一个体积小、实时处理能力强、功耗低、可移植性强的视频模块以满足嵌入式系统设计对速度、功耗和空间的要求和应用开发的需求就成为一个很有意义的课题。本文首先比较了现有的视频应用模块解决方案,根据无线多媒体终端的需求,提出了一个基于USB总线、嵌入式Linux及PXA255微处理器的嵌入式视频模块系统设计方案,同时对方案中需要考虑到的实时性及编解码算法进行了分析,并对模块中需要使用的相关技术作了介绍。在此基础上,分别从硬件和软件两个方面阐述了该模块的实现原理和算法,着重于解决软硬件设计中的难点。在硬件部分,按照处理器核心、USB总线接口和图像采集控制等几个依据功能划分的模块,说明了硬件设计原理和实现方法,重点在于硬件设计的可靠性; 在软件部分,分析了软件系统的构成与实现框架,对各个组成部分及如何提高模块的实时性进行了详细说明。最后,介绍了模块的测试方案和测试结果,对本文的工作进行了总结,给出了模块需要进一步完善和改进的方面,并阐述了视频终端的应用前景。更多还原

【Abstract】 With the rapid development of embedded technology, multimedia technology and the more popularization of wireless communication technology, the application of wireless multimedia terminal (WMT),which blend communication with computation and multimedia, is becoming a new light point of various application development, Video is the very important indispensable component of this application. WMT, as the embedded system, is mostly used in places which have some strict requirements such as speed, power consumption and size. Therefore, it is a very promising field to research how to design a video module with the smallest size, real-time, low in power consumption and porting ability to meet the embedded system requirements and the needs of application. In this paper, we first compare the present solutions for the video module. According to the wireless multimedia terminal (WMT) requirement, the design scheme of an embedded video module based on USB bus, embedded Linux and PXA255 processor is introduced. Meanwhile, the real-time and encoding and decoding algorithms which should be considered in the design scheme are analyzed, the related technologies used in the Video module are introduced. Based on the previous introduction and information, the realization of hardware and software design is explained in detail, emphasis is on difficulties in design. In the hardware part, according to the functionally partitioned modules, such as processor core, USB bus interface and video capture control, the concrete hardware design principles and implement methods are explained, this part emphasizes on the reliability of the module; In the software part, the structure and frame of software system are analyzed, the components of the system software and how to improve the ability of real-time are described. At the end of the paper, the test scheme and the debugging results are introduced; the paper is summarized, some functions models which need consummating are presented, and the applications of the video termination are prospected.更多还原