genexcsid.m

来自「ITU-T G.723.1 Speech Coder: Matlab imple」· M 代码 · 共 33 行

function [es, DecoderMem] = GenExcSID (QC, DecoderMem, DecoderPar)
% SID frame decoder

% DecoderMem.CNG.SIDGain is updated to the received gain value
% DecoderMem.CNG.Gain is updated to the smoothed gain value

% $Id: GenExcSID.m 1.3 2004/07/09 G.723.1-v2r1a $

CNGpar = DecoderPar.CNGpar;

% Extract the codes
GainC = QC.GainC;

% Gain calculation
SIDGain = CNGpar.GainCBook(GainC + 1);   % Decode the transmitted gain
GainP = DecoderMem.CNG.Gain;             % Previous gain

% Update the gain value
FModeP = DecoderMem.CNG.FModeP;
if (FModeP == 0 | FModeP == 1 | FModeP == 2)  % Previous: normal transmitted frame
  GainT = SIDGain;
else                                          % Previous: SID or null
  a = CNGpar.GFactor;
  GainT = (1 - a) * GainP + a * SIDGain;
end
DecoderMem.CNG.SIDGain = SIDGain;
DecoderMem.CNG.Gain = GainT;

% Generate a CNG frame
[es, DecoderMem] = GenExcCNG (GainT, DecoderMem, DecoderPar);

return