嵌入式网络视频软件的研究与实现

发布时间：2018-01-27 22:51

本文关键词： 嵌入式系统软件架构网络视频性能测量　出处：《南京邮电大学》2012年硕士论文　论文类型：学位论文

【摘要】：随着计算技术和图像处理技术的发展,嵌入式系统技术和网络视频应用技术结合的嵌入式网络视频应用逐步普及。但是由于嵌入式系统对处理资源的限制,以及网络视频应用对处理资源的较高要求,必须研究嵌入式网络视频软件的优化方法。为了提高嵌入式软件网络视频处理的实时性、有效地分配嵌入式系统的计算资源,设计和实现了一种基于优先级的、面向嵌入式软件模块的架构。该软件架构对嵌入式系统中网络视频软件重新进行了功能划分,根据网络视频处理中的时序关系和实时性要求分配各个模块的优先级,以最大限度地利用嵌入式系统的计算资源。针对使用信号量或互斥锁机制控制共享资源并发访问所带来的调度延迟,设计和实现了一种基于优先级调度的非阻塞的缓冲区管理模型。测试结果表明,在同等条件下,这些嵌入式网络视频软件的优化方法可以提高视频的播放质量,保证画面播放流畅。网络视频应用的性能经常随着网络负载的变化而变化,因此需要从外部对网络视频传输的性能进行实时测量。针对网络视频中的视频时延测量需求,提出了一种基于RTP的视频的时延测量方法,采用带外数据的方式传递独立于视频数据的时间信息,以提高测量的准确度,并基于对开源软件Live555和VLC的修改,实现了该测量方法,测试结果表明该测量方法具有一定的准确度。
[Abstract]:With the development of computing technology and image processing technology, embedded network video application which combines embedded system technology and network video application technology is becoming more and more popular. As well as the higher requirements of network video applications to deal with resources, we must study the optimization method of embedded network video software. In order to improve the real-time performance of embedded software network video processing and allocate computing resources of embedded system effectively, a priority-based algorithm is designed and implemented. The architecture of embedded software module, which redivides the function of network video software in embedded system. The priority of each module is assigned according to the timing relationship and real-time requirements of network video processing. In order to maximize the utilization of computing resources in embedded systems, the scheduling delay caused by concurrent access to shared resources is controlled by using semaphores or mutex mechanisms. A non-blocking buffer management model based on priority scheduling is designed and implemented. The test results show that under the same conditions these embedded network video software optimization methods can improve the quality of video playback. Make sure the screen plays smoothly. The performance of network video applications often changes with the change of network load, so it is necessary to measure the performance of network video transmission in real time from outside. A time delay measurement method based on RTP is proposed. The time information independent of video data is transmitted by out-of-band data in order to improve the accuracy of measurement. Based on the modification of the open source software Live555 and VLC, the measurement method is realized. The test results show that the method has certain accuracy.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP368.1;TP393.09

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