In the process of interpolation of video and/or audio digital data S.sub.n, an interpolated value is chosen depending on whether or not an edge is detected. The edge detection is performed as follows. Let L=|S.sub.2n-S.sub.2n-2|, C=|S.sub.2n+2-S.sub.2n|, and R=|S.sub.2n+4-S.sub.2n+2|. An edge is detected when R>9(C+L) or L>9(C+R). A predictor P.sub.2n+1=K.sub.1S.sub.2n+K.sub.2S.sub.2n+2 provides the interpolated value for S.sub.2n+1 when an edge is detected, where K.sub.1=k.sub.L/(k.sub.L+k.sub.R), K.sub.2=k.sub.R/(k.sub.L+k.sub.R), where k.sub.L=1/(1+L), k.sub.R=1/(1+R) or k.sub.L=d.sub.2n+1,2n+2/(1+L) and k.sub.R=d.sub.2n,2n+1/(1+R). A different predictor (e.g. a cubic predictor) is used when no edge is detected. Other embodiments are also provided.