码率控制是视频图像编码技术中的重要组成部分，旨在受限的通信带宽下提供最小失真的图像质量同时保证比特流的平稳输出，长期以来既是研究重点也是应用热点。面向中国自主知识产权的新一代音视频编码标准（audio video coding standard 2．0，AVS2）中码率控制技术，将模糊控制理论与码率控制相结合，提出了一种新的码率控制算法。首先根据模糊控制器原理建立快速查询表，接着基于指数率失真模型进行了基本论域到模糊子集论域的映射，而后将假设参考解码缓冲区反馈值及其差值带入模糊控制查询表得出量化参数（Quantiza-tion Parameter，QP）值变化增量。最终的编码过程采用系统 QP 值与增量之和来进行。在通用测试条件下的实验结果表明，新算法比特率失真比率（Bjøntegaard delta bit rate，BDBR，BD-rate）取得增益效果明显，比特率控制精度高。算法实现简洁，计算复杂度低，特别适合恒定目标比特率编码端速率控制。相关成果已被 AVS2标准工作组采纳，集成在参考模型软件 RD10．0中。%Rate control is an essential component of the video coding technology,focusing on providing the minimum distortion of video image quality under the limited bandwidth of communication as much as possible.It is developed as a research hot spot.The work is meant for the new generation of audio video coding standard (AVS2)in the rate control technology,combining the fuzzy control theory and the rate control,a new rate con-trol algorithm is proposed.First,a fast lookup table is created depending on the principle of the industrial fuzzy controller.Second,a mapping from the functional domain to the internal domain is created.Third,an incre-mental quantization parameter (QP)value can be found when taking the hypothetical reference decoder buffer values and its error values into the fuzzy controller query.Finally,the encoder adopts the system QP with its in-crement.The experimental results show that,under the common test condition,the rate control algorithm can achieve significant BD-rate gain and maintain high bit rate accuracy.The proposed algorithm is applied simply with low computational complexity.This proposal particularly suitable for constant target bit rate control.This work is approved by the AVS2 standard working group and integrated into the reference software model RD10.0.
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