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Pseudo-masking curve for the MDCT

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This commit is contained in:
Jean-Marc Valin 2008-01-07 13:36:01 +11:00
parent 825ec60b53
commit 0a3e79aa11
2 changed files with 20 additions and 0 deletions
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18
libcelt/psy.c
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@ -61,6 +61,7 @@ static void spreading_func(float *psd, float *mask, int len, int Fs)
decayR[i] = pow(.1f, deriv);
/* decay corresponding to -25dB/Bark */
decayL[i] = pow(0.0031623f, deriv);
//printf ("%f %f\n", decayL[i], decayR[i]);
}
/* Compute right slope (-10 dB/Bark) */
mem=psd[0];
@ -117,3 +118,20 @@ void compute_masking(float *X, float *mask, int len, int Fs)
}
void compute_mdct_masking(float *X, float *mask, int len, int Fs)
{
int i;
float psd[len];
float mem;
for (i=0;i<len;i++)
mask[i] = X[i]*X[i];
for (i=1;i<len-1;i++)
psd[i] = .5*mask[i] + .25*(mask[i-1]+mask[i+1]);
//psd[0] = .5*mask[0]+.25*(mask[1]+mask[2]);
psd[0] = .5*mask[0]+.5*mask[1];
psd[len-1] = .5*(mask[len-1]+mask[len-2]);
/* TODO: Do tone masking */
/* Noise masking */
spreading_func(psd, mask, len, Fs);
}