ref: 528f4b8660a8eac7e24ca62ff048178f57da0b77
parent: 9375aa4faa9ea7a32b1ae5ba7fd8aebd92949c3a
author: Jean-Marc Valin <[email protected]>
date: Sat Jun 28 23:46:39 EDT 2008
More fixed-point work on the time window -- including conversion of the gain to power-of-two.
--- a/libcelt/celt.c
+++ b/libcelt/celt.c
@@ -55,7 +55,17 @@
static const float gainWindow[16] = {0.0085135, 0.0337639, 0.0748914, 0.1304955, 0.1986827, 0.2771308, 0.3631685, 0.4538658,
0.5461342, 0.6368315, 0.7228692, 0.8013173, 0.8695045, 0.9251086, 0.9662361, 0.9914865};
-
+
+#ifdef FIXED_POINT
+static const celt_word16_t transientWindow[16] = {+ 279, 1106, 2454, 4276, 6510, 9081, 11900, 14872,
+ 17896, 20868, 23687, 26258, 28492, 30314, 31662, 32489};
+#else
+static const float transientWindow[16] = {+ 0.0085135, 0.0337639, 0.0748914, 0.1304955, 0.1986827, 0.2771308, 0.3631685, 0.4538658,
+ 0.5461342, 0.6368315, 0.7228692, 0.8013173, 0.8695045, 0.9251086, 0.9662361, 0.9914865};
+#endif
+
/** Encoder state
@brief Encoder state
*/
@@ -186,7 +196,7 @@
float num, den;
num = end[i]*i;
den = (1000+begin[i])*(len-i)+.01*end[i]*len;
- if (num*maxD > den*maxN && end[i] > .05*begin[i])
+ if ((num*maxD > den*maxN) && (end[i] > .05*begin[i]))
{maxN = num;
maxD = den;
@@ -262,7 +272,7 @@
}
/** Compute the IMDCT and apply window for all sub-frames and all channels in a frame */
-static void compute_inv_mdcts(const CELTMode *mode, int shortBlocks, celt_sig_t *X, int transient_time, float transient_gain, celt_sig_t * restrict out_mem)
+static void compute_inv_mdcts(const CELTMode *mode, int shortBlocks, celt_sig_t *X, int transient_time, int transient_shift, celt_sig_t * restrict out_mem)
{int c, N4;
const int C = CHANNELS(mode);
@@ -272,7 +282,7 @@
for (c=0;c<C;c++)
{int j;
- if (transient_time<0 && C==1 && !shortBlocks) {+ if (transient_shift==0 && C==1 && !shortBlocks) {const mdct_lookup *lookup = MDCT(mode);
mdct_backward(lookup, X, out_mem+C*(MAX_PERIOD-N-N4), mode->window, overlap);
} else if (!shortBlocks) {@@ -288,12 +298,19 @@
/* Prevents problems from the imdct doing the overlap-add */
CELT_MEMSET(x+N4, 0, overlap);
mdct_backward(lookup, tmp, x, mode->window, overlap);
- if (transient_time >= 0)
+ if (transient_shift > 0)
{+#ifdef FIXED_POINT
for (j=0;j<16;j++)
- x[N4+transient_time+j-16] *= 1+gainWindow[j]*(transient_gain-1);
+ x[N4+transient_time+j-16] *= 1-gainWindow[j]+gainWindow[j]*(1<<transient_shift);
for (j=transient_time;j<N+overlap;j++)
- x[N4+j] *= transient_gain;
+ x[N4+j] = SHL32(x[N4+j], transient_shift);
+#else
+ for (j=0;j<16;j++)
+ x[N4+transient_time+j-16] *= 1+gainWindow[j]*((1<<transient_shift)-1);
+ for (j=transient_time;j<N+overlap;j++)
+ x[N4+j] *= 1<<transient_shift;
+#endif
}
/* The first and last part would need to be set to zero if we actually
wanted to use them. */
@@ -323,12 +340,19 @@
tmp[j] = X[C*(j*B+b)+c];
mdct_backward(lookup, tmp, x+N4+N2*b, mode->window, overlap);
}
- if (transient_time >= 0)
+ if (transient_shift > 0)
{+#ifdef FIXED_POINT
for (j=0;j<16;j++)
- x[N4+transient_time+j-16] *= 1+gainWindow[j]*(transient_gain-1);
+ x[N4+transient_time+j-16] = MULT16_32_Q15(SHR16(Q15_ONE-transientWindow[j],transient_shift)+transientWindow[j], SHL32(x[N4+transient_time+j-16],transient_shift));
for (j=transient_time;j<N+overlap;j++)
- x[N4+j] *= transient_gain;
+ x[N4+j] = SHL32(x[N4+j], transient_shift);
+#else
+ for (j=0;j<16;j++)
+ x[N4+transient_time+j-16] *= 1+gainWindow[j]*((1<<transient_shift)-1);
+ for (j=transient_time;j<N+overlap;j++)
+ x[N4+j] *= 1<<transient_shift;
+#endif
}
/* The first and last part would need to be set to zero if we actually
wanted to use them. */
@@ -361,7 +385,7 @@
#endif
int shortBlocks=0;
int transient_time;
- float transient_gain;
+ int transient_shift;
float maxR;
const int C = CHANNELS(st->mode);
SAVE_STACK;
@@ -397,35 +421,41 @@
ec_enc_bits(&st->enc, 1, 1);
if (maxR < 30)
{- transient_time = 16;
- transient_gain = 1;
- ec_enc_bits(&st->enc, 0, 2);
+ transient_shift = 0;
} else if (maxR < 100)
{- transient_gain = 2;
- ec_enc_bits(&st->enc, 1, 2);
+ transient_shift = 1;
} else if (maxR < 500)
{- transient_gain = 4;
- ec_enc_bits(&st->enc, 2, 2);
+ transient_shift = 2;
} else
{- transient_gain = 8;
- ec_enc_bits(&st->enc, 3, 2);
+ transient_shift = 3;
}
- ec_enc_uint(&st->enc, transient_time, N+st->overlap);
- for (c=0;c<C;c++)
- for (i=0;i<16;i++)
- in[C*(transient_time+i-16)+c] /= 1+gainWindow[i]*(transient_gain-1);
- gain_1 = 1./transient_gain;
- for (c=0;c<C;c++)
- for (i=transient_time;i<N+st->overlap;i++)
- in[C*i+c] *= gain_1;
+ ec_enc_bits(&st->enc, transient_shift, 2);
+ if (transient_shift)
+ ec_enc_uint(&st->enc, transient_time, N+st->overlap);
+ if (transient_shift)
+ {+ for (c=0;c<C;c++)
+ for (i=0;i<16;i++)
+ in[C*(transient_time+i-16)+c] /= 1+gainWindow[i]*((1<<transient_shift)-1);
+#ifdef FIXED_POINT
+ for (c=0;c<C;c++)
+ for (i=transient_time;i<N+st->overlap;i++)
+ in[C*i+c] = SHR32(in[C*i+c], transient_shift);
+#else
+ gain_1 = 1./(1<<transient_shift);
+ for (c=0;c<C;c++)
+ for (i=transient_time;i<N+st->overlap;i++)
+ in[C*i+c] *= gain_1;
+#endif
+ }
shortBlocks = 1;
} else {ec_enc_bits(&st->enc, 0, 1);
transient_time = -1;
- transient_gain = 1;
+ transient_shift = 0;
shortBlocks = 0;
}
/* Pitch analysis: we do it early to save on the peak stack space */
@@ -531,7 +561,7 @@
CELT_MOVE(st->out_mem, st->out_mem+C*N, C*(MAX_PERIOD+st->overlap-N));
- compute_inv_mdcts(st->mode, shortBlocks, freq, transient_time, transient_gain, st->out_mem);
+ compute_inv_mdcts(st->mode, shortBlocks, freq, transient_time, transient_shift, st->out_mem);
/* De-emphasis and put everything back at the right place in the synthesis history */
#ifndef SHORTCUTS
for (c=0;c<C;c++)
@@ -729,7 +759,7 @@
VARDECL(int, stereo_mode);
int shortBlocks;
int transient_time;
- float transient_gain;
+ int transient_shift;
const int C = CHANNELS(st->mode);
SAVE_STACK;
@@ -763,26 +793,14 @@
shortBlocks = ec_dec_bits(&dec, 1);
if (shortBlocks)
{- int gainid = ec_dec_bits(&dec, 2);
- switch(gainid) {- case 0:
- transient_gain = 1;
- break;
- case 1:
- transient_gain = 2;
- break;
- case 2:
- transient_gain = 4;
- break;
- case 3:
- default:
- transient_gain = 8;
- break;
- }
- transient_time = ec_dec_uint(&dec, N+st->mode->overlap);
+ transient_shift = ec_dec_bits(&dec, 2);
+ if (transient_shift)
+ transient_time = ec_dec_uint(&dec, N+st->mode->overlap);
+ else
+ transient_time = 0;
} else {transient_time = -1;
- transient_gain = 1;
+ transient_shift = 0;
}
/* Get the pitch gains */
has_pitch = unquant_pitch(gains, st->mode->nbPBands, &dec);
@@ -828,7 +846,7 @@
CELT_MOVE(st->out_mem, st->out_mem+C*N, C*(MAX_PERIOD+st->overlap-N));
/* Compute inverse MDCTs */
- compute_inv_mdcts(st->mode, shortBlocks, freq, transient_time, transient_gain, st->out_mem);
+ compute_inv_mdcts(st->mode, shortBlocks, freq, transient_time, transient_shift, st->out_mem);
for (c=0;c<C;c++)
{