Lagrangian Multiplier Based Joint Three-Layer Rate Control for H.264/AVC

Lagrangian multiplier (LM) based mode decision is one of the most important technologies in standard H.264/AVC encoder. Based on LM theory, this paper presents a joint three-layer (JTL) model for H.264/AVC rate control. At macroblock (MB) level, we dynamically revise LM for each of MBs by its estimated complexities, which is able to select a better coding mode than the current scheme with the constant LM adopted in H.264/AVC. At frame level, a more flexible and effective quantization parameter (QP) adjustment scheme is designed for I-frame to avoid buffer overflow or underflow. In addition, we also present a new target bits allocation scheme in group of picture (GOP) level. Experimental results show that our JTL model can not only significantly improve the video quality with the average PSNR gain up to 0.97 dB, but also provide a more stable buffer occupancy with respect to other existing rate control methods.