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New LPC-based PLC code

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This commit is contained in:
Jean-Marc Valin 2009-12-11 00:07:31 -05:00
parent 1ccfd3cc03
commit e14fe9046f
2 changed files with 208 additions and 14 deletions
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97
libcelt/celt.c
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@ -1214,16 +1214,15 @@ void celt_decoder_destroy(CELTDecoder *st)
celt_free(st);
}
/** Handles lost packets by just copying past data with the same
offset as the last
pitch period */
#ifdef NEW_PLC
#ifndef FIXED_POINT
#include "plc.c"
#else
#endif
#define LPC_ORDER 24
static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict pcm)
{
int c, N;
int pitch_index;
int overlap = st->mode->overlap;
celt_word16 fade = Q15ONE;
int i, len;
VARDECL(celt_sig, freq);
@ -1231,7 +1230,6 @@ static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict p
int offset;
SAVE_STACK;
N = st->block_size;
ALLOC(freq,C*N, celt_sig); /**< Interleaved signal MDCTs */
len = N+st->mode->overlap;
@ -1241,10 +1239,10 @@ static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict p
celt_word32 tmp=0;
celt_word32 mem0[2]={0,0};
celt_word16 mem1[2]={0,0};
/*find_spectral_pitch(st->mode, st->mode->fft, &st->mode->psy, st->out_mem+MAX_PERIOD-len, st->out_mem, st->mode->window, NULL, len, MAX_PERIOD-len-100, &pitch_index, C);*/
/* FIXME: Should do a bit of interpolation while decimating */
pitch_downsample(st->out_mem, pitch_buf, MAX_PERIOD, MAX_PERIOD, C, mem0, mem1);
pitch_search(st->mode, pitch_buf+((MAX_PERIOD-len)>>1), pitch_buf, len, MAX_PERIOD-len-100, &pitch_index, &tmp);
pitch_downsample(st->out_mem, pitch_buf, MAX_PERIOD, MAX_PERIOD,
C, mem0, mem1);
pitch_search(st->mode, pitch_buf+((MAX_PERIOD-len)>>1), pitch_buf, len,
MAX_PERIOD-len-100, &pitch_index, &tmp);
pitch_index = MAX_PERIOD-len-pitch_index;
st->last_pitch_index = pitch_index;
} else {
@ -1256,6 +1254,8 @@ static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict p
}
offset = MAX_PERIOD-pitch_index;
#ifdef FIXED_POINT
ALLOC(freq,C*N, celt_sig); /**< Interleaved signal MDCTs */
while (offset+len >= MAX_PERIOD)
offset -= pitch_index;
compute_mdcts(st->mode, 0, st->out_mem+offset*C, freq, C);
@ -1265,6 +1265,78 @@ static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict p
CELT_MOVE(st->out_mem, st->out_mem+C*N, C*(MAX_PERIOD+st->mode->overlap-N));
/* Compute inverse MDCTs */
compute_inv_mdcts(st->mode, 0, freq, -1, 0, st->out_mem, C);
#else
for (c=0;c<C;c++)
{
float e[MAX_PERIOD];
float exc[MAX_PERIOD];
float ac[LPC_ORDER+1];
float lpc[LPC_ORDER];
float decay = 1;
celt_word32 mem[LPC_ORDER]={0};
for (i=0;i<MAX_PERIOD;i++)
exc[i] = st->out_mem[i*C+c];
_celt_autocorr(exc, ac, st->mode->window, st->mode->overlap,
LPC_ORDER, MAX_PERIOD);
ac[0] *= 1.0001;
_celt_lpc(lpc, ac, LPC_ORDER);
fir(exc, lpc, exc, MAX_PERIOD, LPC_ORDER, mem);
/* Check if the waveform is decaying (and if so how fast) */
{
float E1=0, E2=0;
int period;
if (pitch_index <= MAX_PERIOD/2)
period = pitch_index;
else
period = MAX_PERIOD/2;
for (i=0;i<period;i++)
{
E1 += exc[MAX_PERIOD-period+i]*exc[MAX_PERIOD-period+i];
E2 += exc[MAX_PERIOD-2*period+i]*exc[MAX_PERIOD-2*period+i];
}
decay = sqrt((E1+1)/(E2+1));
if (decay > 1)
decay = 1;
}
/* Copy excitation, taking decay into account */
for (i=0;i<len+st->mode->overlap;i++)
{
if (offset+i >= MAX_PERIOD)
{
offset -= pitch_index;
decay *= decay;
}
e[i] = decay*exc[offset+i];
}
for (i=0;i<MAX_PERIOD+st->mode->overlap-N;i++)
st->out_mem[C*i+c] = st->out_mem[C*(N+i)+c];
iir(e, lpc, e, len+st->mode->overlap, LPC_ORDER, mem);
/* Apply TDAC to the concealed audio so that it blends with the
previous and next frames */
for (i=0;i<overlap/2;i++)
{
float tmp1, tmp2;
tmp1 = e[i ]*st->mode->window[i ] -
e[overlap-i-1]*st->mode->window[overlap-i-1];
tmp2 = e[N+overlap-1-i]*st->mode->window[i] +
e[N+i ]*st->mode->window[overlap-i-1];
tmp1 *= fade;
tmp2 *= fade;
st->out_mem[C*(MAX_PERIOD+i)+c] = tmp2*st->mode->window[overlap-i-1];
st->out_mem[C*(MAX_PERIOD+overlap-i-1)+c] = tmp2*st->mode->window[i];
st->out_mem[C*(MAX_PERIOD-N+i)+c] += tmp1*st->mode->window[i];
st->out_mem[C*(MAX_PERIOD-N+overlap-i-1)+c] -= tmp1*st->mode->window[overlap-i-1];
}
for (i=0;i<N-overlap;i++)
st->out_mem[C*(MAX_PERIOD-N+overlap+i)+c] = fade*e[overlap+i];
}
#endif
for (c=0;c<C;c++)
{
@ -1282,7 +1354,6 @@ static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict p
RESTORE_STACK;
}
#endif
#ifdef FIXED_POINT
int celt_decode(CELTDecoder * restrict st, const unsigned char *data, int len, celt_int16 * restrict pcm)
@ -1337,8 +1408,6 @@ int celt_decode_float(CELTDecoder * restrict st, const unsigned char *data, int
celt_decode_lost(st, pcm);
RESTORE_STACK;
return 0;
} else {
st->loss_count = 0;
}
if (len<0) {
RESTORE_STACK;
@ -1427,7 +1496,7 @@ int celt_decode_float(CELTDecoder * restrict st, const unsigned char *data, int
compute_inv_mdcts(st->mode, shortBlocks, freq, transient_time, transient_shift, st->out_mem, C);
deemphasis(st->out_mem, pcm, N, C, preemph, st->preemph_memD);
st->loss_count = 0;
RESTORE_STACK;
return 0;
}