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Commit 210ccafa authored by Jean-Marc Valin's avatar Jean-Marc Valin
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Improves fixed-point precision for quant_coarse_energy

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with 8 additions and 8 deletions
libcelt/quant_bands.c
+ 8
− 8
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......@@ -103,7 +103,7 @@ unsigned quant_coarse_energy(const CELTMode *m, int start, celt_word16 *eBands,
prob += 2*m->nbEBands;
}
/* The .8 is a heuristic */
beta = MULT16_16_Q15(QCONST16(.8f,15),coef);
beta = MULT16_16_P15(QCONST16(.8f,15),coef);
/* Encode at a fixed coarse resolution */
for (i=start;i<m->nbEBands;i++)
......@@ -114,10 +114,10 @@ unsigned quant_coarse_energy(const CELTMode *m, int start, celt_word16 *eBands,
celt_word16 q; /* dB */
celt_word16 x; /* dB */
celt_word16 f; /* Q8 */
celt_word16 mean = (i < E_MEANS_SIZE) ? MULT16_16_Q15(Q15ONE-coef,eMeans[i]) : 0;
celt_word16 mean = (i < E_MEANS_SIZE) ? MULT16_16_P15(Q15ONE-coef,eMeans[i]) : 0;
x = eBands[i+c*m->nbEBands];
#ifdef FIXED_POINT
f = x-mean -MULT16_16_Q15(coef,oldEBands[i+c*m->nbEBands])-prev[c];
f = x-mean -MULT16_16_P15(coef,oldEBands[i+c*m->nbEBands])-prev[c];
/* Rounding to nearest integer here is really important! */
qi = (f+128)>>8;
#else
......@@ -138,8 +138,8 @@ unsigned quant_coarse_energy(const CELTMode *m, int start, celt_word16 *eBands,
}
q = SHL16(qi,DB_SHIFT);
oldEBands[i+c*m->nbEBands] = MULT16_16_Q15(coef,oldEBands[i+c*m->nbEBands])+(mean+prev[c]+q);
prev[c] = mean+prev[c]+MULT16_16_Q15(Q15ONE-beta,q);
oldEBands[i+c*m->nbEBands] = MULT16_16_P15(coef,oldEBands[i+c*m->nbEBands])+(mean+prev[c]+q);
prev[c] = mean+prev[c]+MULT16_16_P15(Q15ONE-beta,q);
} while (++c < C);
}
return bits_used;
......@@ -234,7 +234,7 @@ void unquant_coarse_energy(const CELTMode *m, int start, celt_ener *eBands, celt
prob += 2*m->nbEBands;
}
/* The .8 is a heuristic */
beta = MULT16_16_Q15(QCONST16(.8f,15),coef);
beta = MULT16_16_P15(QCONST16(.8f,15),coef);
/* Decode at a fixed coarse resolution */
for (i=start;i<m->nbEBands;i++)
......@@ -243,7 +243,7 @@ void unquant_coarse_energy(const CELTMode *m, int start, celt_ener *eBands, celt
do {
int qi;
celt_word16 q;
celt_word16 mean = (i < E_MEANS_SIZE) ? MULT16_16_Q15(Q15ONE-coef,eMeans[i]) : 0;
celt_word16 mean = (i < E_MEANS_SIZE) ? MULT16_16_P15(Q15ONE-coef,eMeans[i]) : 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)
......@@ -252,7 +252,7 @@ void unquant_coarse_energy(const CELTMode *m, int start, celt_ener *eBands, celt
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_Q15(coef,oldEBands[i+c*m->nbEBands])+(mean+prev[c]+q);
oldEBands[i+c*m->nbEBands] = MULT16_16_P15(coef,oldEBands[i+c*m->nbEBands])+(mean+prev[c]+q);
prev[c] = mean+prev[c]+MULT16_16_Q15(Q15ONE-beta,q);
} while (++c < C);
}
......
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