Rate Control For H.264/AVC Encoders Using Hierarchical B Frames

Rate control is an essential technique in video coding applications, whose ultimeta objective is to optimizate the video coding quality under certain restraints of network condition, channel bandwidth and buffer capacity. At present, conventional rate control algorithms are studied and designed for the traditional structures (e.g. IPPP or IBBP), and seldom investigations on rate control for the new temporal scalable structure, i.e., hierarchical B frames. Therefore, this paper is devoted to this field and has investigated on a new frame layer rate control algorithm for the hierarchical B frames structures.The advancements of the investigated algorithm are as follows.1. The quantization parameter (QP) of the first I frame of the sequence is adaptively determined based on the available channel bandwidth, frame rate, picture size and the characteristics of the input video.2. The target bits of each group of pictures is calculated based on target bit-rate and fullness of buffer.3. The QP for the current picture is determined according to the characteristics of coded pictures and quadratic rate distortion model.Experimental results demonstrate that when the investigated rate control scheme is applied to the coding structure with hierarchical B frames using H.264/AVC encoder, the actual coding bit rates match the target bit rates much more well than the conventional ones, and the rate distortion performance is also improved by 0.1~0.33dB.