Structural Similarity Optimal MB Layer Rate Control Algorithm for H.264

Conventional Rate Control (RC) schemes take mostly objective metric as distortion measurement, which can not acquire optimal subjective quality. This paper applies Structural SIMilarity (SSIM) based subjective distortion to Rate Distortion Optimization (RDO) and RC in H.264 video coding, and proposes a SSIM optimal MacroBlock (MB) layer RC algorithm. First, an empirical SSIM linear distortion model is put forward. Then an improved quadratic Rate-Quantization (R-Q) model is combined to obtain the close-form solution of SSIM optimal MB layer quantization step by Lagrange multiplier. Experimental results show that the proposed method preserves much more image structural information and thus acquires better subjective quality compared with objective quality optimal MB layer RC scheme JVT-O016.