Comment on "Shape-adaptive DCT for generic coding of video"

Contrary to one of the key conclusions of the paper by Sikora and Makai (see ibid., vol.5, no.1, p.5962, 1995), the cross-correlation of the one-dimensional shape-adaptive DCT (1-D SA-DCT) coefficients located in two columns of different sizes does not necessarily take maximum values at the same indices. The correct way to measure the cross-correlation of the SA-DCT coefficients after the first stage of the transform is presented. The idea of implementing shape-adaptive DCT and some aspects of their work could nevertheless be useful.