Patent ID: 8626517

Claim:
A frequency-domain noise shaping method for interpolating a spectral shape and a time-domain envelope of a quantization noise in a windowed and transform-coded audio signal, comprising: splitting transform coefficients of the windowed and transform-coded audio signal into a plurality of spectral bands; and for each spectral band: calculating a first gain representing, together with corresponding gains calculated for the other spectral bands, a spectral shape of the quantization noise at a first transition between a first time window and a second time window; calculating a second gain representing, together with corresponding gains calculated for the other spectral bands, a spectral shape of the quantization noise at a second transition between the second time window and a third time window; and an operation of filtering the transform coefficients of the second time window, the filtering operation receiving as first input the transform coefficients of the second time window and as second input the first and second gains to filter said transform coefficients of the second time window using the second input, first and second gains to interpolate between the first and second transitions the spectral shape and the time-domain envelope of the quantization noise.