ref: c803ee195996ae485ac838dc442d519724fbf861
parent: 2e8ba5483df15415db29ea3029080c45321e1ad8
author: Jean-Marc Valin <[email protected]>
date: Thu May 13 20:17:31 EDT 2010
Entropy-coding the new split parameter. Uses a triangular PDF for coding the angle.
--- a/libcelt/bands.c
+++ b/libcelt/bands.c
@@ -457,7 +457,7 @@
split = stereo = Y != NULL;
- if (b>(60<<BITRES) && !stereo && LM>0)
+ if (b>(32<<BITRES) && !stereo && LM>0)
{N /= 2;
Y = X+N;
@@ -472,7 +472,10 @@
int mbits, sbits, delta;
int qalloc;
celt_word16 mid, side;
- qb = (b-2*(N-1)*(QTHETA_OFFSET-m->logN[i]-(LM<<BITRES)))/(32*(N-1));
+ if (N>1)
+ qb = (b-2*(N-1)*(QTHETA_OFFSET-m->logN[i]-(LM<<BITRES)))/(32*(N-1));
+ else
+ qb = b-2;
if (qb > (b>>BITRES)-1)
qb = (b>>BITRES)-1;
if (qb<0)
@@ -499,7 +502,27 @@
int shift;
shift = 14-qb;
itheta = (itheta+(1<<shift>>1))>>shift;
- ec_enc_uint(enc, itheta, (1<<qb)+1);
+ if (stereo || qb>9)
+ ec_enc_uint(enc, itheta, (1<<qb)+1);
+ else {+ int j;
+ int fl=0, fs=1, ft;
+ j=0;
+ while(1)
+ {+ if (j==itheta)
+ break;
+ fl+=fs;
+ if (j<(1<<qb>>1))
+ fs++;
+ else
+ fs--;
+ j++;
+ }
+ ft = ((1<<qb>>1)+1)*((1<<qb>>1)+1);
+ qalloc = log2_frac(ft,BITRES) - log2_frac(fs,BITRES) + 1;
+ ec_encode(enc, fl, fl+fs, ft);
+ }
itheta <<= shift;
}
if (itheta == 0)
@@ -587,7 +610,7 @@
if (stereo)
quant_band(m, i, Y, NULL, N, sbits, spread, NULL, resynth, enc, remaining_bits, LM, NULL, NULL);
else
- quant_band(m, i, Y, NULL, N, sbits, spread, lowband+N, resynth, enc, remaining_bits, LM, NULL, NULL);
+ quant_band(m, i, Y, NULL, N, sbits, spread, lowband ? lowband+N : NULL, resynth, enc, remaining_bits, LM, NULL, NULL);
}
} else {@@ -644,7 +667,7 @@
split = stereo = Y != NULL;
- if (b>(60<<BITRES) && !stereo && LM>0)
+ if (b>(32<<BITRES) && !stereo && LM>0)
{N /= 2;
Y = X+N;
@@ -657,7 +680,10 @@
int itheta;
int mbits, sbits, delta;
int qalloc, qb;
- qb = (b-2*(N-1)*(QTHETA_OFFSET-m->logN[i]-(LM<<BITRES)))/(32*(N-1));
+ if (N>1)
+ qb = (b-2*(N-1)*(QTHETA_OFFSET-m->logN[i]-(LM<<BITRES)))/(32*(N-1));
+ else
+ qb = b-2;
if (qb > (b>>BITRES)-1)
qb = (b>>BITRES)-1;
if (qb>14)
@@ -671,7 +697,29 @@
} else {int shift;
shift = 14-qb;
- itheta = ec_dec_uint(dec, (1<<qb)+1);
+ if (stereo || qb>9)
+ itheta = ec_dec_uint(dec, (1<<qb)+1);
+ else {+ int fs=1, fl=0;
+ int j, fm, ft;
+ ft = ((1<<qb>>1)+1)*((1<<qb>>1)+1);
+ fm = ec_decode(dec, ft);
+ j=0;
+ while (1)
+ {+ if (fm < fl+fs)
+ break;
+ fl+=fs;
+ if (j<(1<<qb>>1))
+ fs++;
+ else
+ fs--;
+ j++;
+ }
+ itheta = j;
+ qalloc = log2_frac(ft,BITRES) - log2_frac(fs,BITRES) + 1;
+ ec_dec_update(dec, fl, fl+fs, ft);
+ }
itheta <<= shift;
}
if (itheta == 0)
@@ -740,7 +788,7 @@
if (stereo)
unquant_band(m, i, Y, NULL, N, sbits, spread, NULL, dec, remaining_bits, LM, NULL);
else
- unquant_band(m, i, Y, NULL, N, sbits, spread, lowband+N, dec, remaining_bits, LM, NULL);
+ unquant_band(m, i, Y, NULL, N, sbits, spread, lowband ? lowband+N : NULL, dec, remaining_bits, LM, NULL);
}
} else {--- a/libcelt/rate.h
+++ b/libcelt/rate.h
@@ -41,7 +41,7 @@
#define BITRES 4
#define FINE_OFFSET 50
-#define QTHETA_OFFSET 40
+#define QTHETA_OFFSET 35
#define BITOVERFLOW 30000