Subjective Quality Optimized Intra Mode Selection for H.264 I Frame Coding Based on SSIM

H.264/AVC adopts rate distortion optimization (RDO) technique to select optimal macro block (MB) coding mode and achieves higher compression efficiency, but the traditional RDO framework employs pixel wise mean square error (MSE) and the like as objective distortion metric, which can not acquire optimal subjective quality. This paper applies structural similarity (SSIM) based subjective distortion to RDO-based intra mode decision in H.264 I frame coding, and further proposes a frame layer adaptive Lagrange multiplier adjustment scheme to get better tradeoff between rate and SSIM distortion. Experimental results show that, the proposed scheme encodes more image structural information and thus acquires better subjective quality and coding efficiency compared with MSE-based RDO method.