基于综合因子的H.264码率控制算法

摘要

针对H.264的JVT-G012算法在帧层对未编码的P帧采用平均分配比特、忽略了图像复杂度和P帧在图像组(Group of pictures,GOP)中的位置对码率控制影响的问题,提出了一种新的H.264码率控制算法,先利用P帧的图像复杂度和P帧在GOP中位置组成的综合因子来调整P帧的目标比特分配,再利用已编码帧的历史信息来调整当前编码帧的量化参数.通过实验表明,与JVT-G012算法相比,本文算法不仅提高了视频图像的质量,尤其是运动剧烈和纹理复杂的视频序列的图像质量,而且使得输出的实际码率更接近目标码率,提高了码率控制的精准性;与已有算法相比,在保持视频图像质量的情况下,进一步提高了码率控制的精准性.%Aiming at improving the quality of video images and the accuracy of the rate control,a new rate control algorithm for H.264 is proposed.Firstly,the target bit allocation is modulated according to the coeficient composed by the complexity of the P frame and its position in the group of pictures (GOP).Then,The current coding frame's quantization parameters are modulated according to the coded frames.Experimental results show that the proposed algorithm,compared with the JVT-G012 algorithm,improves the quality of video images,especially when the movement becomes severe or the texture is complex in video squences.It can also achieve an output of the actual code rate closer to the target bits.Compared with the other algorithm,the proposed algorithm retains the quality of video images and improves the accuracy of rate control.