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.