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fixed-point: More work on the PLC

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This commit is contained in:
Jean-Marc Valin 2010-06-17 20:10:02 -04:00
parent 0da0d91ba7
commit 7b7f07120e
2 changed files with 23 additions and 16 deletions
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36
libcelt/celt.c
View file

@ -1514,8 +1514,8 @@ static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict p
celt_word32 e[2*MAX_PERIOD]; celt_word32 e[2*MAX_PERIOD];
celt_word16 exc[2*MAX_PERIOD]; celt_word16 exc[2*MAX_PERIOD];
celt_word32 ac[LPC_ORDER+1]; celt_word32 ac[LPC_ORDER+1];
float decay = 1; celt_word16 decay = 1;
float S1=0; celt_word32 S1=0;
celt_word16 mem[LPC_ORDER]={0}; celt_word16 mem[LPC_ORDER]={0};
offset = MAX_PERIOD-pitch_index; offset = MAX_PERIOD-pitch_index;
@ -1528,12 +1528,20 @@ static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict p
LPC_ORDER, MAX_PERIOD); LPC_ORDER, MAX_PERIOD);
/* Noise floor -40 dB */ /* Noise floor -40 dB */
#ifdef FIXED_POINT
ac[0] += SHR32(ac[0],13);
#else
ac[0] *= 1.0001; ac[0] *= 1.0001;
#endif
/* Lag windowing */ /* Lag windowing */
for (i=1;i<=LPC_ORDER;i++) for (i=1;i<=LPC_ORDER;i++)
{ {
/*ac[i] *= exp(-.5*(2*M_PI*.002*i)*(2*M_PI*.002*i));*/ /*ac[i] *= exp(-.5*(2*M_PI*.002*i)*(2*M_PI*.002*i));*/
#ifdef FIXED_POINT
ac[i] -= MULT16_32_Q15(2*i*i, ac[i]);
#else
ac[i] -= ac[i]*(.008*i)*(.008*i); ac[i] -= ac[i]*(.008*i)*(.008*i);
#endif
} }
_celt_lpc(st->lpc+c*LPC_ORDER, ac, LPC_ORDER); _celt_lpc(st->lpc+c*LPC_ORDER, ac, LPC_ORDER);
@ -1542,7 +1550,7 @@ static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict p
/*for (i=0;i<MAX_PERIOD;i++)printf("%d ", exc[i]); printf("\n");*/ /*for (i=0;i<MAX_PERIOD;i++)printf("%d ", exc[i]); printf("\n");*/
/* Check if the waveform is decaying (and if so how fast) */ /* Check if the waveform is decaying (and if so how fast) */
{ {
float E1=0, E2=0; celt_word32 E1=1, E2=1;
int period; int period;
if (pitch_index <= MAX_PERIOD/2) if (pitch_index <= MAX_PERIOD/2)
period = pitch_index; period = pitch_index;
@ -1550,12 +1558,12 @@ static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict p
period = MAX_PERIOD/2; period = MAX_PERIOD/2;
for (i=0;i<period;i++) for (i=0;i<period;i++)
{ {
E1 += exc[MAX_PERIOD-period+i]*exc[MAX_PERIOD-period+i]; E1 += SHR32(MULT16_16(exc[MAX_PERIOD-period+i],exc[MAX_PERIOD-period+i]),8);
E2 += exc[MAX_PERIOD-2*period+i]*exc[MAX_PERIOD-2*period+i]; E2 += SHR32(MULT16_16(exc[MAX_PERIOD-2*period+i],exc[MAX_PERIOD-2*period+i]),8);
} }
decay = sqrt((E1+1)/(E2+1)); if (E1 > E2)
if (decay > 1) E1 = E2;
decay = 1; decay = celt_sqrt(frac_div32(SHR(E1,1),E2));
} }
/* Copy excitation, taking decay into account */ /* Copy excitation, taking decay into account */
@ -1564,18 +1572,18 @@ static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict p
if (offset+i >= MAX_PERIOD) if (offset+i >= MAX_PERIOD)
{ {
offset -= pitch_index; offset -= pitch_index;
decay *= decay; decay = MULT16_16_Q15(decay, decay);
} }
e[i] = decay*SHL32(EXTEND32(exc[offset+i]), SIG_SHIFT); e[i] = SHL32(EXTEND32(MULT16_16_Q15(decay, exc[offset+i])), SIG_SHIFT);
S1 += st->out_mem[offset+i]*1.*st->out_mem[offset+i]; S1 += SHR32(MULT16_16(st->out_mem[offset+i],st->out_mem[offset+i]),8);
} }
iir(e, st->lpc+c*LPC_ORDER, e, len+st->mode->overlap, LPC_ORDER, mem); iir(e, st->lpc+c*LPC_ORDER, e, len+st->mode->overlap, LPC_ORDER, mem);
{ {
float S2=0; celt_word32 S2=0;
for (i=0;i<len+overlap;i++) for (i=0;i<len+overlap;i++)
S2 += e[i]*1.*e[i]; S2 += SHR32(MULT16_16(e[i],e[i]),8);
/* This checks for an "explosion" in the synthesis (including NaNs) */ /* This checks for an "explosion" in the synthesis (including NaNs) */
if (!(S1 > 0.2f*S2)) if (!(S1 > 0.2f*S2))
{ {
@ -1583,7 +1591,7 @@ static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict p
e[i] = 0; e[i] = 0;
} else if (S1 < S2) } else if (S1 < S2)
{ {
float ratio = sqrt((S1+1)/(S2+1)); float ratio = sqrt((S1+1.)/(S2+1.));
for (i=0;i<len+overlap;i++) for (i=0;i<len+overlap;i++)
e[i] *= ratio; e[i] *= ratio;
} }

3
libcelt/plc.c
View file

@ -24,7 +24,7 @@ static celt_word32 frac_div32(celt_word32 a, celt_word32 b)
#endif #endif
float _celt_lpc( void _celt_lpc(
celt_word16 *_lpc, /* out: [0...p-1] LPC coefficients */ celt_word16 *_lpc, /* out: [0...p-1] LPC coefficients */
const celt_word32 *ac, /* in: [0...p] autocorrelation values */ const celt_word32 *ac, /* in: [0...p] autocorrelation values */
int p int p
@ -76,7 +76,6 @@ int p
for (i=0;i<p;i++) for (i=0;i<p;i++)
_lpc[i] = ROUND16(lpc[i],16); _lpc[i] = ROUND16(lpc[i],16);
#endif #endif
return error;
} }
void fir(const celt_word16 *x, void fir(const celt_word16 *x,