Patent ID: 8731917

Claim:
A method of controlling a postfilter for improving perceived quality of speech reconstructed at a speech decoder, the method comprises the steps of: measuring, by a postfilter control device, stationarity of a speech signal by determining a spectral distance between adjacent frames of a speech signal reconstructed at the decoder, determining, by the postfilter control device, a coefficient to a postfilter attenuation control parameter based on the measured stationarity, and transmitting, from the postfilter control device, the determined coefficient to a postfilter, such that the postfilter can process the reconstructed speech signal by applying the determined coefficient to the postfilter attenuation control parameter to obtain an enhanced speech signal; wherein the determined coefficient is a linear combination of a first parameter being a measure of the spectral distance and a second parameter being a measure of how far said spectral distance is to a low-passed spectral distance, θ smooth , of past frames.