DIFFERENTIAL CODING FOR SCALABLE AUDIO CODERS

摘要

The invention relates to a method for coding discrete time signals (x1) sampled at a first sampling rate. According to said method second time signals (x2) are generated using the first time signals, the band width of which corresponds to a second sampling rate which is lower than the first. The second time signals are coded in accordance with a first coding algorithm. The coded second time signals (x2c) are decoded again so as to obtain coded/decoded second time signals (x2cd), the band width of which corresponds to the second sampling rate. The first time signals are transformed by frequency range transformation into first spectral values (X1). From the coded/decoded second time signals second spectral values (X2cd) are generated, which are a representation of the coded/decoded second time signals in the frequency range. To obtain weighted spectral values the first spectral values are weighted with the second spectral values, whereby the first and second spectral values have the same frequency and time resolution. The weighted spectral values (Xb) are coded, taking into consideration a psychoacoustic model, in accordance with a second coding algorithm and entered into a bit stream.