Improvement on Rate-Distortion Performance of H.264 Rate Control in Low Bit Rate

This paper points out some defects in the techniques used in H.264 rate control and presents several new algorithms to improve them. The improved algorithm has the following main features: 1) the bits allocated to each P-frame is proportional to the local motion in it, i.e, more bits are allocated to a frame if the local motion in it is stronger; 2) the quantization parameter for I-frame is choosed based on a new bits allocation scheme for I-frame; 3)the quantization parameter calculation is based on a simple encoding complexity prediction scheme, which is more robust and of less complexity than the quadratic model used by H.264 in low bit rate video coding. Experimental results and analysis show that the improved rate-control scheme has significantly increased the average peak signal-to-noise ratio up to 1.53 dB, reduced the variation of buffer level, improved the perpetual quality of the reconstructed video and reduced the computation complexity.