ref: 1bc8a2e4b17c840e806856a7b7f44c4d118d4662
parent: ac72c2821abf0a054f9598b7c1b7f5533a6289bd
author: Jean-Marc Valin <[email protected]>
date: Tue Mar 25 18:09:32 EDT 2008
optimisation: spreading_func now in-place with no branch in the loop and half the multiplications
--- a/libcelt/psy.c
+++ b/libcelt/psy.c
@@ -78,7 +78,7 @@
}
#endif
-static void spreading_func(const struct PsyDecay *d, celt_word32_t *psd, celt_mask_t *mask, int len)
+static void spreading_func(const struct PsyDecay *d, celt_word32_t * restrict psd, int len)
{int i;
celt_word32_t mem;
@@ -87,22 +87,20 @@
mem=psd[0];
for (i=0;i<len;i++)
{- mask[i] = MULT16_32_Q15(Q15ONE-d->decayR[i],psd[i]) + MULT16_32_Q15(d->decayR[i],mem);
- if (mask[i]<1)
- mask[i]=1;
- mem = mask[i];
+ /* psd = (1-decay)*psd + decay*mem */
+ psd[i] = EPSILON + psd[i] + MULT16_32_Q15(d->decayR[i],mem-psd[i]);
+ mem = psd[i];
}
/* Compute left slope (-25 dB/Bark) */
- mem=mask[len-1];
+ mem=psd[len-1];
for (i=len-1;i>=0;i--)
{/* 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];
+ /* psd = (1-decay)*psd + decay*mem */
+ psd[i] = EPSILON + psd[i] + MULT16_32_Q15(decayL,mem-psd[i]);
+ mem = psd[i];
}
/*for (i=0;i<len;i++) printf ("%f ", mask[i]); printf ("\n");*/#if 0 /* Prints signal and mask energy per critical band */
@@ -141,7 +139,7 @@
mask[i] = ADD32(MULT16_16(X[i*2], X[i*2]), MULT16_16(X[i*2+1], X[i*2+1]));
/* TODO: Do tone masking */
/* Noise masking */
- spreading_func(decay, mask, mask, N);
+ spreading_func(decay, mask, N);
}
#if 0 /* Not needed for now, but will be useful in the future */