Variable Bit Rate Fuzzy Control for Low Delay Video Coding

Release Date:2017-06-13 Author:ZHONG Min, ZHOU Yimin, LUO Minke, and ZUO Wen Click:

[Abstract] Rate control plays a critical role in achieving perceivable video quality under a variable bit rate, limited buffer sizes and low delay applications. Since a rate control system exhibits non⁃linear and unpredictable characteristics, it is difficult to establish a very accurate rate⁃distortion (R⁃D) model and acquire effective rate control performance. Considering the excellent control ability and low computing complexity of the fuzzy logic in non⁃linear systems, this paper proposes a bit⁃rate control algorithm based on a fuzzy controller, named the Fuzzy Rate Control Algorithm (FRCA), for All⁃Intra (AI) and low⁃delay (LD) video source coding. Contributions of the proposed FRCA mainly consist of four aspects. First, fuzzy logic is adopted to minimize the deviation between the actual and the target buffer size in the hypothetical reference decoder (HRD). Second, a fast lookup table is employed in fuzzy rate control, which reduces computing cost of the control process. Third, an input domain determination scheme is proposed to improve the precision of the fuzzy controller. Fourth, a novel scene change detection is introduced and integrated in the FRCA to adaptively adjust the Group⁃of⁃Pictures (GOP) length when the source content fluctuates. The FRCA can be transplanted and implemented in various industry coders. Extensive experiments show that the FRCA has accurate variable bit⁃rate control ability and maintains a steady buffer size during the encoding processes. Compared with the default configuration encoding under AI and LD, the proposed FRCA can achieve the target bit rates more accurately in various classical encoders.

[Keywords] rate control; video coding; fuzzy control; bit per pixel; rate⁃distortion model

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