CONSTRAINED FILTER ENCODING OF POLYPHONIC SIGNALS

摘要

Signals of different channels (c1-cN) are combined into one mono signal (x). A set of adaptive filters, preferably one for each channel (c-cN), is derived in a respective filter adaptation unit (30:1-30:N). when an adaptive filter is applied to the mono signal (x) it reconstructs the signal of the respective channel (c1-cN) under a perceptual constraint. The perceptual constraint is a gain and/or shape constraint. The gain constraint allows the preservation of the relative energy between the channels (c1-cN) while the shape constraint allows more stability by avoiding unnecessary filtering of spectrum nulls. The transmitted parameters are the mono signal (x), in encoded form, and the parameters (p1-pN) of the adaptive filters, preferably also encoded. The receiver reconstructs the signal of the different channels by applying the adaptive filters and possibly some additional post-processing.