Patent ID: 7693710
Filing Date: 2010-04-06
Classification: G10L

Abstract:
1. A method of concealing frame erasure caused by frames of an encoded sound signal erased during transmission from an encoder to a decoder, comprising: determining, in the encoder, concealment/recovery parameters related to the sound signal; transmitting to the decoder concealment/recovery parameters determined in the encoder; and in the decoder, conducting frame erasure concealment and decoder recovery in response to the received concealment/recovery parameters; wherein: conducting frame erasure concealment and decoder recovery comprises, when at least one onset frame is lost, constructing a periodic excitation part artificially as a low-pass filtered periodic train of pulses separated by a pitch period; the method comprises quantizing a position of a first glottal pulse with respect to the beginning of the onset frame prior to transmission of said position of the first glottal pulse to the decoder; and constructing the periodic excitation part comprises realizing the low-pass filtered periodic train of pulses by: centering a first impulse response of a low-pass filter on the quantized position of the first glottal pulse with respect to the beginning of the onset frame; and placing remaining impulse responses of the low-pass filter each with a distance corresponding to an average pitch value from the preceding impulse response up to the end of a last subframe affected by the artificial construction of the periodic part.