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Better comments in the PLC

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This commit is contained in:
Jean-Marc Valin 2012-11-29 17:59:50 -05:00
parent def001bd12
commit 0094c88105
1 changed files with 19 additions and 7 deletions
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26
celt/celt_decoder.c
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@ -441,6 +441,8 @@ static void celt_decode_lost(CELTDecoder * OPUS_RESTRICT st, opus_val16 * OPUS_R
for (i=0;i<MAX_PERIOD;i++)
exc[i] = ROUND16(out_mem[c][i], SIG_SHIFT);
/* Compute LPC coefficients for the last MAX_PERIOD samples before the loss so we can
work in the excitation-filter domain */
if (st->loss_count == 0)
{
_celt_autocorr(exc, ac, mode->window, overlap,
@ -468,9 +470,12 @@ static void celt_decode_lost(CELTDecoder * OPUS_RESTRICT st, opus_val16 * OPUS_R
/* Samples just before the beginning of exc */
for (i=0;i<LPC_ORDER;i++)
mem[i] = ROUND16(out_mem[c][-1-i], SIG_SHIFT);
/* Compute the excitation for MAX_PERIOD samples before the loss */
celt_fir(exc, lpc+c*LPC_ORDER, exc, MAX_PERIOD, LPC_ORDER, mem);
/*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)
We do this to avoid adding energy when concealing in a segment
with decaying energy */
{
opus_val32 E1=1, E2=1;
int period;
@ -489,10 +494,10 @@ static void celt_decode_lost(CELTDecoder * OPUS_RESTRICT st, opus_val16 * OPUS_R
attenuation = decay;
}
/* Move everything one frame to the left */
/* Move memory one frame to the left */
OPUS_MOVE(decode_mem[c], decode_mem[c]+N, DECODE_BUFFER_SIZE-N+overlap);
/* Copy excitation, taking decay into account */
/* Extrapolate excitation with the right period, taking decay into account */
for (i=0;i<len;i++)
{
opus_val16 tmp;
@ -505,13 +510,18 @@ static void celt_decode_lost(CELTDecoder * OPUS_RESTRICT st, opus_val16 * OPUS_R
tmp = ROUND16(out_mem[c][-N+offset+i],SIG_SHIFT);
S1 += SHR32(MULT16_16(tmp,tmp),8);
}
/* Last samples correctly decoded */
/* Last samples correctly decoded so we can have a continuous signal */
for (i=0;i<LPC_ORDER;i++)
mem[i] = ROUND16(out_mem[c][MAX_PERIOD-N-1-i], SIG_SHIFT);
/* Apply the fading if not the first loss */
for (i=0;i<len;i++)
e[i] = MULT16_32_Q15(fade, e[i]);
/* Synthesis filter -- back in the signal domain */
celt_iir(e, lpc+c*LPC_ORDER, e, len, LPC_ORDER, mem);
/* Check if the synthesis energy is higher than expected, which can
happen with the signal changes during our window. If so, attenuate. */
{
opus_val32 S2=0;
for (i=0;i<len;i++)
@ -542,12 +552,14 @@ static void celt_decode_lost(CELTDecoder * OPUS_RESTRICT st, opus_val16 * OPUS_R
}
}
/* Apply pre-filter to the MDCT overlap for the next frame (post-filter will be applied then) */
/* Apply pre-filter to the MDCT overlap for the next frame because the
post-filter will be re-applied in the decoder after the MDCT overlap */
comb_filter(etmp, out_mem[c]+MAX_PERIOD, st->postfilter_period, st->postfilter_period, st->overlap,
-st->postfilter_gain, -st->postfilter_gain, st->postfilter_tapset, st->postfilter_tapset,
NULL, 0);
/* Simulate TDAC on the concealed audio so that it blends with the next frames */
/* Simulate TDAC on the concealed audio so that it blends with the
MDCT of next frames. */
for (i=0;i<overlap/2;i++)
{
opus_val32 tmp;