ref: 0b9e9ce465b9d7158365c746ea1e145be6315fdf
parent: 5d774e075ea5a810f40c3dd0f966ed463c4b89f0
author: Jean-Marc Valin <[email protected]>
date: Wed Aug 4 20:07:33 EDT 2010
cleanup in qb-related code
--- a/libcelt/bands.c
+++ b/libcelt/bands.c
@@ -637,7 +637,7 @@
if (split)
{- int qb;
+ int qb, qn;
int itheta=0;
int mbits, sbits, delta;
int qalloc;
@@ -649,20 +649,22 @@
N2 = 2*N-1;
if (stereo && N==2)
N2--;
- qb = (b+N2*offset)/(N2<<BITRES);
- if (qb > (b>>(BITRES+1))-1)
- qb = (b>>(BITRES+1))-1;
+ qb = (b+N2*offset)/(N2);
+ if (qb > (b>>1)-(1<<BITRES))
+ qb = (b>>1)-(1<<BITRES);
if (qb<0)
- qb = 0;
- if (qb>14)
- qb = 14;
+ qb = 0;
+ if (qb>14<<BITRES)
+ qb = 14<<BITRES;
+ qb >>= BITRES;
+ qn = 1<<qb;
+
qalloc = 0;
- if (qb!=0)
+ if (qn!=1)
{- int shift;
- shift = 14-qb;
+ int shift=14-qb;
if (encode)
{@@ -688,23 +690,23 @@
/* Entropy coding of the angle. We use a uniform pdf for the
first stereo split but a triangular one for the rest. */
- if (stereo || qb>8 || B>1)
+ if (stereo || qn>256 || B>1)
{if (encode)
- ec_enc_uint((ec_enc*)ec, itheta, (1<<qb)+1);
+ ec_enc_uint((ec_enc*)ec, itheta, qn+1);
else
- itheta = ec_dec_uint((ec_dec*)ec, (1<<qb)+1);
- qalloc = log2_frac((1<<qb)+1,BITRES);
+ itheta = ec_dec_uint((ec_dec*)ec, qn+1);
+ qalloc = log2_frac(qn+1,BITRES);
} else {int fs=1, ft;
- ft = ((1<<qb>>1)+1)*((1<<qb>>1)+1);
+ ft = ((qn>>1)+1)*((qn>>1)+1);
if (encode)
{int fl;
- fs = itheta <= (1<<qb>>1) ? itheta + 1 : (1<<qb) + 1 - itheta;
- fl = itheta <= (1<<qb>>1) ? itheta*(itheta + 1)>>1 :
- ft - (((1<<qb) + 1 - itheta)*((1<<qb) + 2 - itheta)>>1);
+ fs = itheta <= (qn>>1) ? itheta + 1 : qn + 1 - itheta;
+ fl = itheta <= (qn>>1) ? itheta*(itheta + 1)>>1 :
+ ft - ((qn + 1 - itheta)*(qn + 2 - itheta)>>1);
ec_encode((ec_enc*)ec, fl, fl+fs, ft);
} else {@@ -712,7 +714,7 @@
int fm;
fm = ec_decode((ec_dec*)ec, ft);
- if (fm < ((1<<qb>>1)*((1<<qb>>1) + 1)>>1))
+ if (fm < ((qn>>1)*((qn>>1) + 1)>>1))
{itheta = (isqrt32(8*(celt_uint32)fm + 1) - 1)>>1;
fs = itheta + 1;
@@ -720,10 +722,10 @@
}
else
{- itheta = (2*((1<<qb) + 1)
+ itheta = (2*(qn + 1)
- isqrt32(8*(celt_uint32)(ft - fm - 1) + 1))>>1;
- fs = (1<<qb) + 1 - itheta;
- fl = ft - (((1<<qb) + 1 - itheta)*((1<<qb) + 2 - itheta)>>1);
+ fs = qn + 1 - itheta;
+ fl = ft - ((qn + 1 - itheta)*(qn + 2 - itheta)>>1);
}
ec_dec_update((ec_dec*)ec, fl, fl+fs, ft);