Different principles for Lossy compression

What is "unnecessary" ?

Averaging ( + repetition/pattern ) (clever forced digitisation)

Range Reduction : from 32 bits to 16 bits, to 8 bits (clever forced quantisation)

issues : classical music ( Orff - Carmina Burana : o Fortuna , Ravel's Boléro )  / subtleties in high contrasted pictures

Variation in Quantisation


Use the way human perception works : more receptive to high frequencies

E.g. : we see better objects that move, we notice the edge of things more than the centers

Frame difference Compression

In video, sending information only about what did change from a key frame (head talking in front of a fixed background)