You mean you didn't understand this when you were 5? > In simple terms, the Discrete Cosine Transform takes a set of N correlated (similar) data-points and ret

You mean you didn't understand this when you were 5? > In simple terms, the Discrete Cosine Transform takes a set of N correlated (similar) data-points and returns N de-correlated (dis-similar) data-points (coefficients) in such a way that the energy is compacted in only a few of the coefficients M where M << N. Did you even nursery?