基于H.265的流媒体技术研究

发布时间：2018-05-18 08:55

本文选题：H.265 + MPEG-DASH　；参考：《武汉理工大学》2014年硕士论文

【摘要】：随着网络不断的建设以及超清、高清视频数量的增加，流媒体业务在整个网络流量中占的比重不断提高，由此也使国内外对流媒体技术进行不断的研究，针对目前流媒体解决方案的缺点，本文提出了一个由H.265和MPEG-DASH相结合的流媒体解决方案。本文首先分析了高效视频压缩标准H.265的关键技术，探讨了H.265视频质量评价相关内容，选取PSNR和SSIM两个参数对H.265视频质量进行客观评价。其次研究了MPEG-DASH相关技术，对目前的自适应算法进行了分析，结合H.265视频质量评价相关内容提出了基于视频质量的自适应算法，算法在基于带宽的自适应算法基础上在码流切换过程中考虑到视频质量和接收缓冲的使用量及其变化量问题，利用视频质量可以改善码流切换过程画面变化过大的问题。对于缓冲区的考虑，在综合以前算法的基础上主要考虑在缓冲使用过高或过低时码流的切换问题，用matlab平台实现了基于视频质量的自适应算法，对算法的功能进行了仿真验证，改进算法在缓冲区内媒体较少、过多、网络带宽变化较大的情况下性能优于基于带宽的自适应算法。本文在最后结合了H.265和MPEG-DASH实现了一个基于libdash流媒体系统，系统使用MPEG-DASH作为传输协议，服务器端使用H.265来对视频进行压缩，客户端以libdash库为基础采用多线程技术，实现了基于带宽的自适应算法，在局域网和广域网环境中对6种场景下的系统进行测试，测试结果可以看出系统能够对由H.265压缩的dash流进行传输、接收、播放，系统能够根据网络带宽的变化对接收媒体段的码率做出合适的调整，在不同网络环境下能够流畅的观看视频。本文在研究H.265视频压缩技术和MPEG-DASH流媒体技术的基础上，，利用PSNR和SSIM对H.265的视频客观质量进行了评价，并提出了基于视频质量的自适应算法。最后基于libdash库实现了完整的流媒体系统，并在不同场景下测试了系统的功能。本文所实现的系统为以后流媒体系统开发提供了指导。
[Abstract]:With the continuous construction of the network and the increase of the number of high-definition video, the proportion of streaming media service in the whole network traffic is increasing, which makes the streaming media technology constantly studied at home and abroad. Aiming at the shortcomings of the current streaming media solution, this paper proposes a streaming media solution based on H.265 and MPEG-DASH. In this paper, the key technology of H.265 video compression standard is analyzed, and the content of H.265 video quality evaluation is discussed. Two parameters, PSNR and SSIM, are selected to evaluate H.265 video quality objectively. Secondly, the MPEG-DASH correlation technology is studied, the current adaptive algorithm is analyzed, and the video quality adaptive algorithm based on H.265 video quality evaluation is proposed. Based on the bandwidth-based adaptive algorithm, the video quality and the usage of receive buffers and their variations are taken into account in the process of bitstream handover. The video quality can be used to improve the problem of excessive picture change in the process of bitstream handover. For the consideration of buffer, based on the previous algorithm, the switching problem of high or too low buffer is considered. The adaptive algorithm based on video quality is implemented by using matlab platform, and the function of the algorithm is verified by simulation. The performance of the improved algorithm is superior to that of the adaptive algorithm based on bandwidth when the media in buffer is less, too much, and the bandwidth of the network changes greatly. At the end of this paper, we combine H.265 and MPEG-DASH to realize a streaming media system based on libdash. The system uses MPEG-DASH as the transmission protocol, H.265 is used to compress the video on the server, and the client uses multithreading technology based on libdash library. An adaptive algorithm based on bandwidth is implemented. The system is tested in six scenarios in LAN and WAN. The test results show that the system can transmit, receive and play the dash stream compressed by H.265. The system can adjust the bit rate of received media segment according to the change of network bandwidth, and can watch video smoothly in different network environment. Based on the research of H.265 video compression technology and MPEG-DASH streaming media technology, the objective quality of H.265 video is evaluated by PSNR and SSIM, and an adaptive algorithm based on video quality is proposed. Finally, a complete streaming media system based on libdash library is implemented, and the functions of the system are tested in different scenarios. The system realized in this paper provides guidance for the future development of streaming media system.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.8

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