为了提高深度图Ⅰ帧的编码效率,提出一种Ⅰ帧宏块模式跳过编码方法.该方法充分考虑了深度图中含有大面积平坦区域,且平坦区域内空间相邻宏块编码模式之间存在较强相关性的特点.在此基础上,提出利用空间相邻已编码宏块模式预测当前宏块模式,并对当前宏块模式与预测模式相等的宏块进行模式跳过编码.进一步提出帧内宏块跳过编码方法,它可以同时跳过平坦区域中宏块模式与残差系数的编码,从而降低现有标准在编码平坦区域宏块的残差系数过程中引入的指示信息冗余.所提两种方法位于宏块模式选择之后的宏块编码阶段,因此对重建帧的质量没有任何影响.实验结果表明:所提两种跳过编码方法的码率平均降低7.83%和8.93%.
Abstract:In order to improve the coding efficiency of the I frame of depth maps,a macro-block (MB) mode skip coding method is proposed.This method fully considers the features of the depth map,namely,large flat areas and strong correlation among the modes of spatial adjacent MBs in the flat areas.On this basis,the modes of spatial adjacent coded MBs are used to predict the current MB mode,and the current MB mode coding is skipped when the predicted mode is equal to the current MB mode.Moreover,an intra MB skip coding method is put forward,which can skip both the MB mode and the quantized residual coefficients of the MBs in the flat areas and can reduce the involved redundancy in the process of coding the coefficients.The two proposed methods have no effect on the quality of the reconstructed frame because they are adopted in the MB coding stage after the MB mode decision.Experimental results show that the two proposed methods bring about bit-rate reduction respectively by 7.83% and 8.93%.