基于i.MX21在嵌入式多媒体系统中的研究和开发

发布时间：2019-01-09 09:02

【摘要】：随着经济发展,人们生活水平的不断提升,基于嵌入式多媒体技术得到了广泛的应用。如娱乐方面,从最初的CD播放机到MP4再到车载娱乐终端和等产品,都是典型的嵌入式多媒体技术的应用；另外由于网络技术的飞速发展,嵌入式多媒体传输技术必将有良好的应用与发展前景。当今运用嵌入式多媒体技术来实现图像通信、视频监控、视频点播和视频会议等功能已经成为研究热点。本文旨在使用基于i.MX21处理器并支持嵌入式Linux系统的多功能嵌入式开发平台对嵌入式多媒体系统进行相关研究和开发,重点研究了在嵌入式多媒体系统中运用MPEG-4技术标准实现硬件编解码的方法以及通过实时传送协议RTP和实时传输控制协RTCP等网络传输技术实现多媒体数据传输的方法。在实际的研究和开发过程中,主要完成了以下的工作：(1)嵌入式多媒体系统的功能需求、软硬件架构以及关键技术,提出了一种基于i.MX21的嵌入式多媒体系统总体结构。(2)通过对FFmpeg软件的相关技术和平台中各硬件模块原理的研究,结合系统的硬件特点,提出了一种在FFmpeg软件中实现硬件编解码的方法,并在实际的环境中实现了该编解码方法。(3)针对现有的MPEG-4打包策略,分析了可以作为计算VOP优先级依据的两个重要因素,提出了一些改进措施,并提出了改进以后优先级的具体计算方法。(4)讨论动态缓冲策略,提出了一种新的调整缓冲区策略,并对该策略进行了详细的具体说明。(5)对接收端的丢帧情况进行了分析,提出了以优先级打包策略为基础的丢帧处理方法和即时播放的方法。最后对本文的主要工作进行了总结,指出了存在的主要问题,并提出了加以改进的基本思路。
[Abstract]:With the development of economy and the improvement of people's living standard, embedded multimedia technology has been widely used. Such as entertainment, from the initial CD player to MP4 to vehicle entertainment terminal and other products, are typical embedded multimedia technology applications; In addition, with the rapid development of network technology, embedded multimedia transmission technology will have a good application and development prospects. Nowadays, embedded multimedia technology is used to realize the functions of image communication, video surveillance, video on demand and video conference. The purpose of this paper is to research and develop embedded multimedia system based on i.MX21 processor and support embedded Linux system. The method of hardware coding and decoding using MPEG-4 technology standard in embedded multimedia system and the method of realizing multimedia data transmission through real-time transmission protocol (RTP) and real-time transmission control co-RTCP (RTCC) technology are studied in this paper. In the actual research and development process, the following work has been accomplished: (1) the functional requirements, hardware and software architecture and key technologies of the embedded multimedia system, An embedded multimedia system architecture based on i.MX21 is proposed. (2) through the research of the related technology of FFmpeg software and the principle of each hardware module in the platform, combined with the hardware characteristics of the system, In this paper, a method of hardware coding and decoding in FFmpeg software is proposed, and the method is implemented in the actual environment. (3) aiming at the existing MPEG-4 packaging strategy, This paper analyzes two important factors that can be used as the basis for calculating VOP priority, puts forward some improvement measures, and puts forward a concrete calculation method of improved priority. (4) dynamic buffer strategy is discussed. In this paper, a new buffer adjustment strategy is proposed, and the strategy is explained in detail. (5) the frame loss at the receiver is analyzed. Based on the priority packing strategy, the method of frame loss and instant playback is proposed. Finally, the main work of this paper is summarized, the main problems are pointed out, and the basic ideas for improvement are put forward.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.81

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