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Should be enough to handle signals with a 144 dB (24-bit) dynamic range

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This commit is contained in:
Jean-Marc Valin 2009-05-23 00:07:08 -04:00
parent 6f18d11148
commit d1d740563a
1 changed files with 8 additions and 8 deletions
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16
libcelt/quant_bands.c
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@ -54,7 +54,7 @@ static inline celt_ener_t dB2Amp(celt_ener_t dB)
celt_ener_t amp;
if (dB>24659)
dB=24659;
amp = PSHR32(celt_exp2(MULT16_16_Q14(21771,dB)),2)-QCONST16(.3f, 14);
amp = PSHR32(celt_exp2(MULT16_16_Q14(21771,dB)),2);
if (amp < 0)
amp = 0;
return PSHR32(amp,2);
@ -64,7 +64,7 @@ static inline celt_ener_t dB2Amp(celt_ener_t dB)
static inline celt_word16_t amp2dB(celt_ener_t amp)
{
/* equivalent to return 6.0207*log2(.3+amp) */
return ROUND16(MULT16_16(24661,celt_log2(ADD32(QCONST32(.3f,14),SHL32(amp,2)))),12);
return ROUND16(MULT16_16(24661,celt_log2(MAX32(QCONST32(.001f,14),SHL32(amp,2)))),12);
/* return DB_SCALING*20*log10(.3+ENER_SCALING_1*amp); */
}
#else
@ -72,7 +72,7 @@ static inline celt_ener_t dB2Amp(celt_ener_t dB)
{
celt_ener_t amp;
/*amp = pow(10, .05*dB)-.3;*/
amp = exp(0.115129f*dB)-.3f;
amp = exp(0.115129f*dB);
if (amp < 0)
amp = 0;
return amp;
@ -80,7 +80,7 @@ static inline celt_ener_t dB2Amp(celt_ener_t dB)
static inline celt_word16_t amp2dB(celt_ener_t amp)
{
/*return 20*log10(.3+amp);*/
return 8.68589f*log(.3f+amp);
return 8.68589f*log(MAX32(.001f,amp));
}
#endif
@ -172,8 +172,6 @@ static unsigned quant_coarse_energy_mono(const CELTMode *m, celt_ener_t *eBands,
q = qi*base_resolution;
oldEBands[i] = mean+MULT16_16_Q15(coef,oldEBands[i])+prev+q;
if (oldEBands[i] < -QCONST16(12.f,8))
oldEBands[i] = -QCONST16(12.f,8);
prev = mean+prev+MULT16_16_Q15(Q15ONE-beta,q);
}
return bits_used;
@ -210,6 +208,8 @@ static void quant_fine_energy_mono(const CELTMode *m, celt_ener_t *eBands, celt_
for (i=0;i<m->nbEBands;i++)
{
eBands[i] = dB2Amp(oldEBands[i]);
if (oldEBands[i] < -QCONST16(40.f,8))
oldEBands[i] = -QCONST16(40.f,8);
}
/*printf ("%d\n", ec_enc_tell(enc, 0)-9);*/
@ -248,8 +248,6 @@ static void unquant_coarse_energy_mono(const CELTMode *m, celt_ener_t *eBands, c
q = qi*base_resolution;
oldEBands[i] = mean+MULT16_16_Q15(coef,oldEBands[i])+prev+q;
if (oldEBands[i] < -QCONST16(12.f,8))
oldEBands[i] = -QCONST16(12.f,8);
prev = mean+prev+MULT16_16_Q15(Q15ONE-beta,q);
}
@ -276,6 +274,8 @@ static void unquant_fine_energy_mono(const CELTMode *m, celt_ener_t *eBands, cel
for (i=0;i<m->nbEBands;i++)
{
eBands[i] = dB2Amp(oldEBands[i]);
if (oldEBands[i] < -QCONST16(40.f,8))
oldEBands[i] = -QCONST16(40.f,8);
}
/*printf ("\n");*/
}