From d1d740563a3ac1d430d61875dfc46f047b767fa1 Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jean-marc.valin@usherbrooke.ca>
Date: Sat, 23 May 2009 00:07:08 -0400
Subject: [PATCH] Should be enough to handle signals with a 144 dB (24-bit)
dynamic range
---
libcelt/quant_bands.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/libcelt/quant_bands.c b/libcelt/quant_bands.c
index 8df6a9fb..03db96f6 100644
--- a/libcelt/quant_bands.c
+++ b/libcelt/quant_bands.c
@@ -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");*/
}