实时移动视频网络自适应QoS技术研究

发布时间：2018-05-19 21:29

本文选题：实时移动视频 + 码率控制　；参考：《华南理工大学》2014年硕士论文

【摘要】：随着近几年科技的飞速发展，移动设备快速普及，移动传输技术大力推进，我们进入了移动互联网时代。在移动互联网应用中，移动视频是不可或缺的一大部分，人们通过移动设备，可以随时随地进行视频会议、观看视频监控、视频点播以及电视直播，移动视频极大地丰富了人们的生活。但由于移动网络传输不稳定以及带宽受限，视频数据在移动网络中传输时容易发生数据丢包、传输时延增大，导致移动视频画面质量下降、播放延时以及不流畅。本课题针对移动视频所遇到的问题，对移动视频QoS相关技术进行了研究。对于移动网络中带宽受限、带宽大小易发生变化导致网络发生拥塞，使得视频播放不流畅的情况，本文提出了一种基于多编码器共用的码率控制技术，该技术在服务端编码模块中采用基于多编码器共用的质量切换机制，使用户在变换视频码率时视频不发生停顿，并且服务端可支持大用户量并发访问，，通过客户端统计数据包的传输时延与丢包率，对网络状况进行估算并向服务端进行反馈控制，服务端根据反馈指令切换用户的视频码率。对于移动网络传输时数据发生丢包，导致视频解码受到影响，造成视频质量下降的情况，文中提出基于网络状况的丢包恢复策略，该策略结合了基于RS编码的前向纠错恢复技术以及限时丢包重传技术，针对不同的网络状况采用合理的丢包恢复技术。本文提出了网络自适应移动视频QoS技术，该技术结合了基于多编码器共用的码率控制技术，使视频码率与网络带宽相匹配，避免网络拥塞，保证视频的实时性与流畅性；结合基于网络状况的丢包恢复策略，降低丢包对视频的影响，保证视频的质量；根据H.264码流与UDP传输的特点，制定了分封包处理策略。本文最后对网络自适应移动视频QoS技术进行了实验与分析，并运用在实时移动视频监控系统中。实验结果表明，通过采用网络自适应移动视频QoS技术，可以解决网络拥塞以及数据丢包所带来的问题，客户端通过移动网络观看视频时，视频的实时性、流畅性与质量得到了保证，QoS技术取得了良好的效果。
[Abstract]:With the rapid development of science and technology, the rapid popularization of mobile devices, mobile transmission technology vigorously promote, we have entered the era of mobile Internet. In mobile Internet applications, mobile video is an indispensable part. Through mobile devices, people can conduct video conferences, watch video surveillance, video on demand and live television at any time and anywhere. Mobile video has greatly enriched people's lives. However, due to the instability of mobile network transmission and bandwidth constraints, video data in the mobile network is prone to packet loss, transmission delay increases, resulting in the degradation of mobile video picture quality, playback delay and not smooth. In order to solve the problem of mobile video, the QoS technology of mobile video is studied in this paper. In this paper, a rate control technique based on multiple encoders is proposed for the mobile network where the bandwidth is limited and the bandwidth is easy to change, which leads to the congestion of the network and makes the video playback not smooth. In the server coding module, a quality switching mechanism based on multi-encoder sharing is adopted, which makes the video not pause when the user changes the video bit rate, and the server can support the concurrent access of the large number of users. The transmission delay and packet loss rate of the data packet are counted by the client, and the network condition is estimated and feedback control is carried out to the server. The server switches the video code rate of the user according to the feedback instruction. In this paper, a packet loss recovery strategy based on network condition is proposed, which results in the loss of packet in mobile network transmission, which results in the video decoding being affected and the video quality declining. The strategy combines forward error correction recovery technology based on RS coding and time-limited packet loss retransmission technology, and adopts reasonable packet loss recovery technology for different network conditions. In this paper, the network adaptive mobile video QoS technology is proposed, which combines the rate control technology based on multiple encoders, which makes the video rate match with the network bandwidth, avoids network congestion, and ensures the real-time and fluency of the video. According to the characteristics of H.264 bitstream and UDP transmission, a packet processing strategy is proposed to reduce the impact of packet loss on video and ensure the quality of video. At the end of this paper, the network adaptive mobile video QoS technology is tested and analyzed, and it is used in the real time mobile video surveillance system. The experimental results show that the network adaptive mobile video QoS technology can solve the problems caused by network congestion and data packet loss, and the real-time performance of the video can be achieved when the client watches the video through the mobile network. Fluency and quality have been guaranteed by QoS technology and good results have been achieved.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN948.6;TP393.09

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