4 May 2018 Multilevel optimal λ decision for low-delay rate control in high-efficiency video coding
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Abstract
By considering the rate distortion optimization (RDO) characteristics, a multilevel optimal λ decision algorithm for the rate control is proposed. With the process of getting the optimal λ for the group of picture (GoP)-level rate control, the frame-level rate control, and the coding tree unit (CTU)-level rate control, a special relationship of the current level λ and the next level λ can be built. First, an approximate linear bit allocation relationship is used between the bit rate and the motion compensation prediction error to assign the bit rate more reasonably for every frame. Second, the multilevel optimal λ decision scheme is proposed. To minimize the whole distortion of a sequence, an effective way is to get the optimal RDO of every GoP. Then, with the RDO process of the GoP-level rate control, an optimal frame λ ratio for each frame in current GoP can be obtained. For the optimal frame λ ratio, its value is mainly decided by the distortion effect, which is calculated by an employed source distortion propagation chain. Finally, an optimal CTU λ clip scheme is proposed to get the optimal RDO of every CTU. The experimental results show that the coding quality of the proposed rate control algorithm is improved significantly with little loss of the bit rate accuracy.
© 2018 SPIE and IS&T
Zhenglong Yang, Guozhong Wang, Guowei Teng, Haiwu Zhao, Guoping Li, "Multilevel optimal λ decision for low-delay rate control in high-efficiency video coding," Journal of Electronic Imaging 27(3), 033003 (4 May 2018). https://doi.org/10.1117/1.JEI.27.3.033003 . Submission: Received: 10 December 2017; Accepted: 10 April 2018
Received: 10 December 2017; Accepted: 10 April 2018; Published: 4 May 2018
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