Abstract: According to the deficient bandwidth and time-varying characteristic of wireless channel for stream media transmission,a multi-mode and adaptive buffer(MMAB) scheme based on combination control of server and client is proposed and is proved to be able to improve the stream media QoS.The basic idea of MMAB is that the system creates the buffer according to working mode,considering large delay jitter and high packets lost rate,designs an improved 2-D index list to reorder the RTP packets fast,adopts ARQ scheme for lost key frames and error mask strategy.The receiver adaptively buffers the RTP packets and compiles statistic of network and channel parameters,the statistic results are transmitted to local PC and the server to adjust the buffer parameters,and the coding rate of the H.264 coder is adjusted to implement congestion control.