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Adding a decision mechanism for turning folding on or off depending on the

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signal characteristics
This commit is contained in:
Jean-Marc Valin 2009-06-02 07:56:19 -04:00
parent d9458cd0b3
commit 527db5c450
3 changed files with 72 additions and 1 deletions
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63
libcelt/bands.c
View file

@ -397,6 +397,69 @@ void deinterleave(celt_norm_t *x, int N)
RESTORE_STACK;
}
int folding_decision(const CELTMode *m, celt_norm_t *X, celt_word16_t *average, int *last_decision)
{
int i;
int NR=0;
celt_word32_t ratio = EPSILON;
const celt_int16_t * restrict eBands = m->eBands;
for (i=0;i<m->nbEBands;i++)
{
int j, N;
int max_i=0;
celt_word16_t max_val=EPSILON;
celt_word32_t floor_ener=EPSILON;
celt_norm_t * restrict x = X+eBands[i];
N = eBands[i+1]-eBands[i];
for (j=0;j<N;j++)
{
if (ABS16(x[j])>max_val)
{
max_val = ABS16(x[j]);
max_i = j;
}
}
#if 0
for (j=0;j<N;j++)
{
if (abs(j-max_i)>2)
floor_ener += x[j]*x[j];
}
#else
floor_ener = QCONST32(1.,28)-MULT16_16(max_val,max_val);
if (max_i < N-1)
floor_ener -= MULT16_16(x[max_i+1], x[max_i+1]);
if (max_i < N-2)
floor_ener -= MULT16_16(x[max_i+2], x[max_i+2]);
if (max_i > 0)
floor_ener -= MULT16_16(x[max_i-1], x[max_i-1]);
if (max_i > 1)
floor_ener -= MULT16_16(x[max_i-2], x[max_i-2]);
floor_ener = MAX32(floor_ener, EPSILON);
#endif
if (N>7 && eBands[i] >= m->pitchEnd)
{
celt_word16_t r;
celt_word16_t den = celt_sqrt(floor_ener);
den = MAX32(QCONST16(.02, 15), den);
r = DIV32_16(SHL32(EXTEND32(max_val),8),den);
ratio = ADD32(ratio, EXTEND32(r));
NR++;
}
}
if (NR>0)
ratio = DIV32_16(ratio, NR);
ratio = ADD32(HALF32(ratio), HALF32(*average));
if (!*last_decision)
{
*last_decision = (ratio < QCONST16(1.8,8));
} else {
*last_decision = (ratio < QCONST16(3.,8));
}
*average = EXTRACT16(ratio);
return *last_decision;
}
/* Quantisation of the residual */
void quant_bands(const CELTMode *m, celt_norm_t * restrict X, celt_norm_t *P, celt_mask_t *W, int pitch_used, celt_pgain_t *pgains, const celt_ener_t *bandE, int *pulses, int shortBlocks, int fold, int total_bits, ec_enc *enc)
{

2
libcelt/bands.h
View file

@ -73,6 +73,8 @@ void denormalise_bands(const CELTMode *m, const celt_norm_t * restrict X, celt_s
*/
int compute_pitch_gain(const CELTMode *m, const celt_norm_t *X, const celt_norm_t *P, celt_pgain_t *gains);
int folding_decision(const CELTMode *m, celt_norm_t *X, celt_word16_t *average, int *last_decision);
/** Quantisation/encoding of the residual spectrum
* @param m Mode data
* @param X Residual (normalised)

8
libcelt/celt.c
View file

@ -78,6 +78,9 @@ struct CELTEncoder {
int pitch_enabled;
int pitch_available;
int delayedIntra;
celt_word16_t tonal_average;
int fold_decision;
int VBR_rate; /* Target number of 16th bits per frame */
celt_word16_t * restrict preemph_memE; /* Input is 16-bit, so why bother with 32 */
celt_sig_t * restrict preemph_memD;
@ -113,6 +116,8 @@ CELTEncoder *celt_encoder_create(const CELTMode *mode)
st->pitch_enabled = 1;
st->pitch_available = 1;
st->delayedIntra = 1;
st->tonal_average = QCONST16(1.,8);
st->fold_decision = 1;
st->in_mem = celt_alloc(st->overlap*C*sizeof(celt_sig_t));
st->out_mem = celt_alloc((MAX_PERIOD+st->overlap)*C*sizeof(celt_sig_t));
@ -652,7 +657,8 @@ int celt_encode_float(CELTEncoder * restrict st, const celt_sig_t * pcm, celt_si
/* Band normalisation */
normalise_bands(st->mode, freq, X, bandE);
if (!shortBlocks && !folding_decision(st->mode, X, &st->tonal_average, &st->fold_decision))
has_fold = 0;
#ifdef EXP_PSY
ALLOC(bandN,C*st->mode->nbEBands, celt_ener_t);
ALLOC(bandM,st->mode->nbEBands, celt_ener_t);