摘要：为有效利用网络资源,提高视频服务的实时性,视频的传输码率应根据网络可用带宽的变化进行调整;对视频传输自适应可用带宽相关技术展开了研究,探讨了自适应实现方法中需要解决的关键技术,通过分析视频种码率控制方法,提出了一种根据可用带宽自适应调节量化步长,优化视频输出码率的策略;实验结果表明,根据网络中链路的带宽状况,自适应改变视频量化步长可以有效地控制视频输出码率,并且能快速而平滑地将视频输出码率调整到一个与网络带宽相适应的值,保证视频网络传输的平稳性和实时性,提高视频服务质量.%Considering utilizing network resources efficiently and the demand of real-time for video based application, the video bit rate should be alterable according to the available network bandwidth.This paper focuses on the self-adaptation variable bandwidth technology for video transmission, and explores the key technologies in the implementation of self-adaptation algorithms.Furthermore, this paper proposes a new scheme which can adapt quantization step depending on the available bandwidth and optimize video output bit- rate by the analysis of kinds of H.246 rate control scheme.Experimental results show that, according to the situation of bandwidth of the network, changing video quantization step size adaptively can be efficient to control the video bit rate.This method can also adjusts video bit rate to a proper value quickly and smoothly, which insures the stationary and real-time of network video transmission and improve the quality of video services.
