ref: 8974f00d53b7c6963904e79fa1f712cf80da8bb3
parent: c7b01bad5018ba110320fd1b674a1d05410c1483
author: Jean-Marc Valin <[email protected]>
date: Fri Mar 19 20:41:39 EDT 2010
fixed-point: improving accuracy of the energy prediction
--- a/libcelt/modes.c
+++ b/libcelt/modes.c
@@ -359,7 +359,7 @@
window[i] = Q15ONE*sin(.5*M_PI* sin(.5*M_PI*(i+.5)/mode->overlap) * sin(.5*M_PI*(i+.5)/mode->overlap));
#else
for (i=0;i<mode->overlap;i++)
- window[i] = MIN32(32767,32768.*sin(.5*M_PI* sin(.5*M_PI*(i+.5)/mode->overlap) * sin(.5*M_PI*(i+.5)/mode->overlap)));
+ window[i] = MIN32(32767,floor(.5+32768.*sin(.5*M_PI* sin(.5*M_PI*(i+.5)/mode->overlap) * sin(.5*M_PI*(i+.5)/mode->overlap))));
#endif
mode->window = window;
--- a/libcelt/quant_bands.c
+++ b/libcelt/quant_bands.c
@@ -88,7 +88,7 @@
{int i, c;
unsigned bits_used = 0;
- celt_word16 prev[2] = {0,0};+ celt_word32 prev[2] = {0,0};celt_word16 coef = m->ePredCoef;
celt_word16 beta;
const int C = CHANNELS(_C);
@@ -109,13 +109,13 @@
int qi;
celt_word16 q;
celt_word16 x;
- celt_word16 f;
- celt_word16 mean = (i-start < E_MEANS_SIZE) ? SUB16(eMeans[i-start], MULT16_16_P15(coef,eMeans[i-start])) : 0;
+ celt_word32 f;
+ celt_word32 mean = (i-start < E_MEANS_SIZE) ? SUB32(SHL32(EXTEND32(eMeans[i-start]),15), MULT16_16(coef,eMeans[i-start])) : 0;
x = eBands[i+c*m->nbEBands];
#ifdef FIXED_POINT
- f = x-mean -MULT16_16_P15(coef,oldEBands[i+c*m->nbEBands])-prev[c];
+ f = SHL32(EXTEND32(x),15)-mean -MULT16_16(coef,oldEBands[i+c*m->nbEBands])-prev[c];
/* Rounding to nearest integer here is really important! */
- qi = (f+QCONST16(.5,DB_SHIFT))>>DB_SHIFT;
+ qi = (f+QCONST32(.5,DB_SHIFT+15))>>(DB_SHIFT+15);
#else
f = x-mean-coef*oldEBands[i+c*m->nbEBands]-prev[c];
/* Rounding to nearest integer here is really important! */
@@ -130,12 +130,12 @@
error[i+c*m->nbEBands] = QCONST16(.5f,DB_SHIFT);
} else {ec_laplace_encode_start(enc, &qi, prob[2*i], prob[2*i+1]);
- error[i+c*m->nbEBands] = f - SHL16(qi,DB_SHIFT);
+ error[i+c*m->nbEBands] = PSHR32(f,15) - SHL16(qi,DB_SHIFT);
}
q = SHL16(qi,DB_SHIFT);
- oldEBands[i+c*m->nbEBands] = MULT16_16_P15(coef,oldEBands[i+c*m->nbEBands])+(mean+prev[c]+q);
- prev[c] = mean+prev[c]+q-MULT16_16_P15(beta,q);
+ oldEBands[i+c*m->nbEBands] = PSHR32(MULT16_16(coef,oldEBands[i+c*m->nbEBands]) + mean + prev[c] + SHL32(EXTEND32(q),15), 15);
+ prev[c] = mean + prev[c] + SHL32(EXTEND32(q),15) - MULT16_16(beta,q);
} while (++c < C);
}
return bits_used;
@@ -219,7 +219,7 @@
void unquant_coarse_energy(const CELTMode *m, int start, celt_ener *eBands, celt_word16 *oldEBands, int budget, int intra, int *prob, ec_dec *dec, int _C)
{int i, c;
- celt_word16 prev[2] = {0, 0};+ celt_word32 prev[2] = {0, 0};celt_word16 coef = m->ePredCoef;
celt_word16 beta;
const int C = CHANNELS(_C);
@@ -239,7 +239,7 @@
do {int qi;
celt_word16 q;
- celt_word16 mean = (i-start < E_MEANS_SIZE) ? SUB16(eMeans[i-start], MULT16_16_P15(coef,eMeans[i-start])) : 0;
+ celt_word32 mean = (i-start < E_MEANS_SIZE) ? SUB32(SHL32(EXTEND32(eMeans[i-start]),15), MULT16_16(coef,eMeans[i-start])) : 0;
/* If we didn't have enough bits to encode all the energy, just assume something safe.
We allow slightly busting the budget here */
if (ec_dec_tell(dec, 0) > budget)
@@ -248,8 +248,8 @@
qi = ec_laplace_decode_start(dec, prob[2*i], prob[2*i+1]);
q = SHL16(qi,DB_SHIFT);
- oldEBands[i+c*m->nbEBands] = MULT16_16_P15(coef,oldEBands[i+c*m->nbEBands])+(mean+prev[c]+q);
- prev[c] = mean+prev[c]+q-MULT16_16_P15(beta,q);
+ oldEBands[i+c*m->nbEBands] = PSHR32(MULT16_16(coef,oldEBands[i+c*m->nbEBands]) + mean + prev[c] + SHL32(EXTEND32(q),15), 15);
+ prev[c] = mean + prev[c] + SHL32(EXTEND32(q),15) - MULT16_16(beta,q);
} while (++c < C);
}
}