FEEDFORWARD PREDICTION OF SCALEFACTORS BASED ON ALLOWABLE DISTORTION FOR NOISE SHAPING IN PSYCHOACOUSTIC-BASED COMPRESSION

摘要

A method of encoding a digital signal, particularly an audio signal, which predicts favorable scalefactors for different frequency subbands of the signal. Distortion thresholds which are associated with each of the frequency subbands of the signal are used, along with transform coefficients, to calculate total scaling values, one for each of the frequency subbands, such that the product of a transform coefficient for a given subband with its respective total scaling value is less than a corresponding one of the distortion thresholds (34). In an encoding application, the distortion thresholds are based on psychoacoustic masking. Encoding of the signal further includes the steps of setting global gain factor to this minimum nonzero value, and quantizing (37) the transform coefficients (38) using the global gain factor and the scalefactors.