METHOD AND DEVICE FOR ERROR CONCEALMENT IN AN ENCODED AUDIO-SIGNAL AND METHOD AND DEVICE FOR DECODING AN ENCODED AUDIO SIGNAL

摘要

A method for error concealment in an encoded audio signal, whereby a set of spectral coefficients are divided into at least two sub-bands(14), whereupon said sub-bands undergo reverse transformation (16). A specific prediction is performed (18) for each quasi- time signal of a sub-band in order to obtain an estimated temporal representation for a sub-band of a set of spectral coefficients following on from a real set. Forward transformation (20) of the time signal of each sub-band provides estimated spectral coefficients that can be used (28) instead of defective spectral coefficients of a subsequent set of spectral coefficients in order to conceal transmission errors, for example. Sub-band transformation provides independence from transformation characteristics such as frame length, window type or MDCT algorithm, while at the same time ensuring that spectral processing is maintained for error concealment, whereby the spectral characteristics of audio signals can also be taken into account during said error concealment.