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.

I. Introduction

The rapid development and evolution of multimedia and network technologies have stimulated the explosion of various video services such as videophone, mobile video, surveillance, digital camera, TV broadcasting and so on. And recently there has been an increasing trend of using HD or even ultra HD videos in practical applications, where videos involve plenty of useful information and corresponding coding technologies become critical for effective storage or transmission. In order to further compress abundant data and accommodate various services with different resolutions, scenarios, and terminals, the new generation video standard of H.265/HEVC [1] is formulated aiming at higher performance, where various advanced tools are incorporated for further improving the coding efficiency. So the H.265/HEVC is gradually gaining a wide interest in research and industrial, such as fast coding algorithms [2], [3], efficiency improvement algorithms [4] and so on.