After PE generation, the HS embedding procedure is per- formed to obtain marked prediction error ei. First, for a histogram of PE (PEH), a peak bin with highest frequency and a zero bin with zero frequency in the histogram should be determined and denoted as (P1, Z1). HS then shifts the histogram bins between P1 and Z1 towards Z1 direction by one unit to create a vacant position near P1. Finally, each predictive error ei is scanned to embed 1-bit message w when P1 is encountered. When P1 < Z1, HS is performed towards ’right direction’ as shown in Fig. 1 and computed by