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Method and device for efficient frame erasure concealment in linear predictive based speech codecs

DC
  • US 7,693,710 B2
  • Filed: 05/30/2003
  • Issued: 04/06/2010
  • Est. Priority Date: 05/31/2002
  • Status: Active Grant
First Claim
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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.

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