Optimal Frame-Level Bit Allocation in HEVC with Distortion Dependency Model

Rate control plays a critical role in video coding for regulating the coded bit-stream to meet the target bit-rate, which relates to two aspects: bit allocation and quantization parameter acquirement. Here, the former is a key element to directly affect the following operation and performance of rate control. So in this paper, an efficient frame-level bit allocation algorithm is established for H.265/HEVC encoder. The characteristic regarding the dependency of inter-frame distortion is first deduced from the theoretical analysis. Then the involved distortion propagation factor is extracted and employed for constructing the bit allocation model. Experimental results show that the proposed method can guarantee a good consistency between the coded bits and target bits, where a PSNR improvement of about 0.132dB is observed compared with the original H.265/HEVC rate control while keeping the same bit-rate.