一种有效的初始量化参数选择算法  

Effective selection algorithm of initial quantization parameters

作　　者：缪广忠[1] 林其伟[1] 

机构地区：[1]华侨大学信息科学与工程学院,福建泉州362021

出　　处：《计算机应用》2010年第2期330-332,340,共4页journal of Computer Applications

摘　　要：在网络环境中,码率控制是影响数字视频质量的重要机制之一。针对提案JVT-G012算法中I帧量化参数选择的不合理造成的视频图像质量(PSNR)低、波动大的问题,提出了一种基于R-Q模型的I帧量化参数选择算法。首先,通过曲线拟合得到I帧的R-Q模型;其次,利用已编码帧的信息更新I帧相对于P帧的权重,为I帧分配合理的目标比特数;最后,在该目标比特下由R-Q模型计算得到I帧量化参数。实验结果表明:与H.264/AVC原算法相比,改进的算法在准确控制码率的同时,视频图像平均质量得到提高且更加平稳。Rate control is one of the most important mechanisms affecting digital video quality in network environments. As for the problem for low-quality and fluctuation of video images in JVT-G012 algorithm, caused by unreasonable choice of I-frame quantization parameter, this paper put forward a selection algorithm of I-frame quantization parameter, based on the R- Q model. Firstly, R-Q model of I-frame was got by curve fitting; secondly, the information of encoded frames was used to update I-frame weight relative to P-frame, and a reasonable target-bit was allocated for I-frame; finally, I-frame quantization parameter was calculated under the target-bit by R-Q model. Simulation results show that compared to the H. 264/AVC standard algorithm, the improved algorithm accurately controls the bit-rate while improving the average PSNR of testing sequences, and makes the quality of video images more stable and smooth.

关 键 词：码率控制 JVT—G012 R—Q模型 量化参数 峰值信噪比 

分 类 号：TN919.81[电子电信—通信与信息系统] TP391.41[电子电信—信息与通信工程]