METHOD AND DEVICE FOR ATTENUATING ECHOES OF A DIGITAL AUDIO SIGNAL DERIVED FROM A MULTILAYER ENCODER

摘要

The invention relates to a method for detection and elimination of echoes on decoding a digital audio signal achieved by multilayer encoding comprising a transform encoding which generates echoes and a predictive encoding which does not generate echoes. The method comprises at least a decoding, comparing the value of the relationship of a representation of the time envelope for the signal decided by transformation with that for the signal decoded in a predictive manner and if the value of said relationship is greater or equal to a threshold value, to deduce the existence of an echo from the decoding by transformation, if not, if the value of the relationship less than said threshold to deduce the absence of an echo and to carry out attenuation, conditional on there being an echo, of the signals from decoding by transformation. A further aspect of the invention relates to the generation of a false alarm message on decoding a digital audio signal to make the decoding dependent on an echo detection step.