实时流媒体系统中音视频同步的设计与实现

发布时间：2018-03-15 04:01

本文选题：实时流媒体　切入点：音视频同步　出处：《浙江工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：进入21世纪,伴随着经济的高速发展,整个社会的不安定因素逐渐累积,人们的安全意识也是逐渐加强。而计算机技术、高压缩比的数据压缩技术以及宽带通信技术的发展,为安防等实时流媒体系统应用领域的发展带来了新的增长点。随着应用的多样化,单一的视频监控显得有些单调,已逐渐满足不了客户的需求,无论是银行、铁路、客运站,都需要优质的音视频监控系统提供较全面的安防服务。由于网络传输的不可靠性,导致本应保持同步关系的数据,到达信宿端时已失去了其固有的时间关联性,即失去了同步,因此音视频的同步性能就成为了实时流媒体系统中的一个聚焦热点。为此,本文就实时流媒体系统中音视频媒体流的同步问题做了探究。设计并实现一个简易的实时流媒体系统,该系统包括信源端、流媒体服务器、信宿端三部分。针对音视频数据在传输过程中产生异步的情况,设计了一个基于RTP/RTCP协议的网络自适应控制的实时流媒体同步方案。该方案从信源端、信宿端、网络状况三方面入手对音视频实施同步控制。在信源端实现了音视频数据的同步采集、编码；音视频数据在发送前通过打上时间戳,实现不同媒体映射到同一条时间轴。在信宿端,第一步是对收到的音视频包进行同步预处理,消除时延抖动导致的乱序。然后分别对音频进行解压,对视频进行组帧。最终依据时间戳值对音视频数据实施同步控制。在网络状况的自适应方面,信宿端统计网络延时抖动与丢包,一方面依据统计信息调节信宿端缓存和播放速率,另一方面将统计信息反馈给信源端。信源端再依据接收的信息调节视频压缩率,实现发送端的码率调节。最后经过实验证明,本实时流媒体系统在正常的网络环境下具备良好的音视频同步性能。
[Abstract]:In 21th century, with the rapid development of economy, the unstable factors of the whole society gradually accumulated, and people's security consciousness was gradually strengthened, while the development of computer technology, high compression ratio data compression technology and broadband communication technology, Along with the diversification of application, the single video surveillance appears to be a bit monotonous, and can not meet the needs of customers, whether it is the bank, railway, passenger station, and so on, which brings a new growth point for the development of real-time streaming media system, such as security and defense. Because of the unreliability of the network transmission, the data which should have kept synchronous relation have lost its inherent time correlation, that is to say, the synchronization has already been lost when arriving at the terminal of the destination, because of the unreliability of the network transmission, because of the high quality audio and video surveillance system to provide the more comprehensive security service. Therefore, the synchronization performance of audio and video has become a hot spot in real-time streaming media system. This paper probes into the synchronization of audio and video media flow in real-time streaming media system, and designs and implements a simple real-time streaming media system, which includes the source end, streaming media server, and so on. Aiming at the asynchronous situation of audio and video data transmission, a real-time streaming media synchronization scheme based on network adaptive control based on RTP/RTCP protocol is designed. The synchronization control of audio and video is implemented in three aspects of network status. The synchronous acquisition and coding of audio and video data are realized at the source end, and the audio and video data are timestamped before transmission. The first step is to synchronize the received audio and video packets to eliminate the disorder caused by the delay jitter, and then decompress the audio frequency separately. Finally, according to the time stamp value, the audio and video data are controlled synchronously. In the adaptive aspect of the network condition, the terminal counts the network delay jitter and packet loss. On the one hand, the buffer and playback rate is adjusted according to the statistical information, on the other hand, the statistical information is fed back to the source end. The source side adjusts the video compression ratio according to the received information, and realizes the rate adjustment of the sending side. Finally, the experiment proves that, The real-time streaming media system has good audio and video synchronization performance under the normal network environment.
【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.8

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