A fast rate-distortion optimization algorithm for H.264/AVC

In H.264/AVC video coding standard, Rate distortion optimization (RDO) is a very efficient technique to decide the coding mode of the macroblock and improves the coding performance greatly. But at the same time, RDO introduces a great deal of computation complexity because it needs to do the transform and entropy coding to get accurate distortion and bit-rate to calculate the Lagrange cost. In order to avoid the expensive computational cost, in this paper, a simple and accurate bit estimation model is proposed and used in RDO scheme. Combined with distortion measure method in transform domain and the fast intra mode RDO method, a lot of computation of RDO is reduced. Experimental results prove that our proposed fast RDO algorithm can reduce about 60% total encoding time and save about 76% computation time of RDO module with little degradation in coding performance.