shithub: opus

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Simplified spreading function so that only one set of coefficients (the right
slope is required).

--- a/libcelt/psy.c

+++ b/libcelt/psy.c

@@ -51,7 +51,7 @@

 {

    int i;

    decay->decayR = celt_alloc(sizeof(float)*len);

-   decay->decayL = celt_alloc(sizeof(float)*len);

+   /*decay->decayL = celt_alloc(sizeof(float)*len);*/

    for (i=0;i<len;i++)

    {

       float f;

@@ -65,7 +65,7 @@

       /* decay corresponding to -10dB/Bark */

       decay->decayR[i] = Q15ONE*pow(.1f, deriv);

       /* decay corresponding to -25dB/Bark */

-      decay->decayL[i] = Q15ONE*pow(0.0031623f, deriv);

+      /*decay->decayL[i] = Q15ONE*pow(0.0031623f, deriv);*/

       /*printf ("%f %f\n", decayL[i], decayR[i]);*/

    }

 }

@@ -73,7 +73,7 @@

 void psydecay_clear(struct PsyDecay *decay)

 {

    celt_free(decay->decayR);

-   celt_free(decay->decayL);

+   /*celt_free(decay->decayL);*/

 }

 static void spreading_func(struct PsyDecay *d, celt_word32_t *psd, celt_mask_t *mask, int len)

@@ -94,7 +94,10 @@

    mem=mask[len-1];

    for (i=len-1;i>=0;i--)

    {

-      mask[i] = MULT16_32_Q15(Q15ONE-d->decayL[i],mask[i]) + MULT16_32_Q15(d->decayL[i],mem);

+      /* Left side has around twice the slope as the right side, so we just

+         square the coef instead of storing two sets of decay coefs */

+      celt_word16_t decayL = MULT16_16_Q15(d->decayR[i], d->decayR[i]);

+      mask[i] = MULT16_32_Q15(Q15ONE-decayL,mask[i]) + MULT16_32_Q15(decayL,mem);

       if (mask[i]<1)

          mask[i]=1;

       mem = mask[i];

--- a/libcelt/psy.h

+++ b/libcelt/psy.h

@@ -34,7 +34,7 @@

 #include "arch.h"

 struct PsyDecay {

-   celt_word16_t *decayL;

+   /*celt_word16_t *decayL;*/

    celt_word16_t *decayR;

 };