Video Coding Rate Control Strategy

Rate control is one of the key techniques of the multimedia communications especially on the Internet which the bandwidth can't be predicted or be controlled .Rate control play a decisive rule on the service quality of the multimedia system.In this paper, the key video coding technology is analyzed at first and then based on this, the key points of the stream control in video coding has been researched including of DCT, quantization and buffer control etc. In the end form the transmission, we research the stream control by considering the bandwidth and propose a scheme of stream control based on DCT coefficient.In quantization step quantization gene is an important parameter in video stream control. The enactment of this parameter is determined by buffer occupancy. Stream control based on buffer-quantization-gene change is the key technology of the stream control. However the adjustment of the quantization gene based on the buffer occupancy maybe cause the graph dithering when decoded it or the difference of one frame that means the quality on the top of the frame is better than that of on the bottom of the frame. In this paper, we analyze the limitation of this technique and give a revised scheme in which the revised part is added. When the wrap of graph is caused the revise part will fill in the free channel and improves the graph quality.The control arithmetic based on bandwidth-adaptive transmission is a keystone of the innovation in this paper. According to the detection bandwidth in real time from the receiver, the sender chooses the different modes of delamination coding, smoothes the stream and transmits it to the receiver. This scheme is flexible to adapt various bandwidth networks. Experiments show that the service quality of MPEG stream is improved efficiently using this rate control scheme and it is ideal rate control scheme.