H.264基本单元层码率控制的改进算法

摘要

针对H.264码率控制标准算法中对基本单元的平均绝对差(MAD)值预测时只利用了时间相关性而使预测结果不够精确的缺陷,提出一种基本单元层码率控制的改进算法.该算法同时考虑时空相关性来提高MAD值预测精度,并运用时空方向MAD值变化趋势来动态修正MAD预测值.实验结果表明,改进算法与JM8.6原算法相比,不仅能更精确控制码率,还能使平均亮度峰值信噪比(PSNR)得到提高.%In the standard H. 264 algorithm, only time relevance is used while predicting the Mean Absolute Difference (MAD). Therefore, an improved rate control algorithm of basic unit layer was introduced combining the time prediction and space prediction, while taking advantage of the change tendency of MAD. When compared with the standard rate control algorithm, adopted by the JVT H.264 reference software JM8.6, the proposed rate control algorithm can not only reduce the mismatch between actual bit rates and target ones, but also increase the average luminance Peak Signal-to-Noise ( PSNR) of reconstructed video.