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Fix bias in LPC spectrum

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This commit is contained in:
Jean-Marc Valin 2019-04-10 21:13:44 -04:00
parent fd1fc693aa
commit a3300d7b24
1 changed files with 4 additions and 1 deletions
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5
dnn/freq.c
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@ -47,6 +47,9 @@ static const opus_int16 eband5ms[] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 20, 24, 28, 34, 40
};
static const float compensation[] = {
0.8f, 1.f, 1.f, 1.f, 1.f, 1.f, 1.f, 1.f, 0.666667f, 0.5f, 0.5f, 0.5f, 0.333333f, 0.25f, 0.25f, 0.2f, 0.166667f, 0.173913f
};
typedef struct {
int init;
@ -233,7 +236,7 @@ float lpc_from_cepstrum(float *lpc, const float *cepstrum)
RNN_COPY(tmp, cepstrum, NB_BANDS);
tmp[0] += 4;
idct(Ex, tmp);
for (i=0;i<NB_BANDS;i++) Ex[i] = pow(10.f, Ex[i]);
for (i=0;i<NB_BANDS;i++) Ex[i] = pow(10.f, Ex[i])*compensation[i];
return lpc_from_bands(lpc, Ex);
}