流媒体应用中,为了满足可用带宽的变化常需要动态地调整比特流码率。由于H.264/AVC支持同步预测(SP)帧,并允许在大范围内的不同质量比特流之间进行切换,而MPEG-4又支持FGS编码,使得比特流小范围可调,因此为了充分利用两者的优点,给出一种将两者融合在一起的解决方案,并采用自适应码率选择方法,使传输的比特流既能适应网络传输带宽的大范围变化,又能灵活适应小范围的带宽波动,且平均峰值信噪比值可较明显提高。

In order to content with the constraint of available bandwidth variation,the sever needs to switch bitstreams dynamically in streaming applications.H.264/AVC supports SP-frame that enables high efficiency of switching among bitstreams of different qualities over larger bandwidth,and over little bandwidth fine granularity scalability video coding is supported by MPEG-4.In the paper,for make good use of the two advantage propose a seamless bitstream switching scheme that combines two tools and use self-adaptation bit-rate selection scheme for both high bandwidth variations of networks and low bandwidth variations,which is efficient for improving average PSNR from experience results.