void Lsp_get_quant(
Word16 lspcb1[][M], /* (i) Q13 : first stage LSP codebook */
Word16 lspcb2[][M], /* (i) Q13 : Second stage LSP codebook */
Word16 code0, /* (i) : selected code of first stage */
Word16 code1, /* (i) : selected code of second stage */
Word16 code2, /* (i) : selected code of second stage */
Word16 fg[][M], /* (i) Q15 : MA prediction coef. */
Word16 freq_prev[][M], /* (i) Q13 : previous LSP vector */
Word16 lspq[], /* (o) Q13 : quantized LSP parameters */
Word16 fg_sum[] /* (i) Q15 : present MA prediction coef. */
)
{
Word16 j;
Word16 buf[M]; /* Q13 */
for ( j = 0 ; j < NC ; j++ )
buf[j] = add( lspcb1[code0][j], lspcb2[code1][j] );
for ( j = NC ; j < M ; j++ )
buf[j] = add( lspcb1[code0][j], lspcb2[code2][j] );
Lsp_expand_1_2(buf, GAP1);
Lsp_expand_1_2(buf, GAP2);
Lsp_prev_compose(buf, lspq, fg, freq_prev, fg_sum);
Lsp_prev_update(buf, freq_prev);
Lsp_stability( lspq );
return;
}
/* lsf_decode */
void Lsp_get_quant(
Word16 lspcb1[][M], /* (i) Q13 : first stage LSP codebook */
Word16 lspcb2[][M], /* (i) Q13 : Second stage LSP codebook */
Word16 code0, /* (i) : selected code of first stage */
Word16 code1, /* (i) : selected code of second stage */
Word16 code2, /* (i) : selected code of second stage */
Word16 fg[][M], /* (i) Q15 : MA prediction coef. */
Word16 freq_prev[][M], /* (i) Q13 : previous LSP vector */
Word16 lspq[], /* (o) Q13 : quantized LSP parameters */
Word16 fg_sum[] /* (i) Q15 : present MA prediction coef. */
)
{
static const UWord8 gap[2]={GAP1, GAP2};
Word16 j, i;
Word16 buf[M]; /* Q13 */
Word32 diff, acc;
for ( j = 0 ; j < NC ; j++ )
{
buf[j] = lspcb1[code0][j] + lspcb2[code1][j];
buf[j+NC] = lspcb1[code0][j+NC] + lspcb2[code2][j+NC];
}
/* Lsp_expand_1_2 */
for (i = 0; i < 2; ++i)
for ( j = 1 ; j < M ; j++ )
{
diff = (buf[j-1] - buf[j] + gap[i]) >> 1;
if ( diff > 0 )
{
buf[j-1] -= diff;
buf[j] += diff;
}
}
/* Lsp_prev_compose
* compose LSP parameter from elementary LSP with previous LSP. */
for ( i = 0 ; i < M ; i++ ) {
acc = buf[i] * fg_sum[i];
for ( j = 0 ; j < MA_NP ; j++ )
acc += freq_prev[j][i] * fg[j][i];
lspq[i] = acc >> 15;
}
/* Lsp_prev_update */
for ( j = MA_NP-1 ; j > 0 ; j-- )
Copy(freq_prev[j-1], freq_prev[j], M);
Copy(buf, freq_prev[0], M);
Lsp_stability( lspq );
}
void sid_lsfq_decode(Word16 *index, /* (i) : quantized indices */
Word16 *lspq, /* (o) : quantized lsp vector */
Word16 freq_prev[MA_NP][M] /* (i) : memory of predictor */
)
{
Word32 acc0;
Word16 i, j, k, lsfq[M], tmpbuf[M];
/* get the lsf error vector */
Copy(lspcb1[PtrTab_1[index[1]]], tmpbuf, M);
for (i=0; i<M/2; i++)
tmpbuf[i] = add(tmpbuf[i], lspcb2[PtrTab_2[0][index[2]]][i]);
for (i=M/2; i<M; i++)
tmpbuf[i] = add(tmpbuf[i], lspcb2[PtrTab_2[1][index[2]]][i]);
/* guarantee minimum distance of 0.0012 (~10 in Q13) between tmpbuf[j]
and tmpbuf[j+1] */
for (j=1; j<M; j++){
acc0 = L_mult(tmpbuf[j-1], 16384);
acc0 = L_mac(acc0, tmpbuf[j], -16384);
acc0 = L_mac(acc0, 10, 16384);
k = extract_h(acc0);
if (k > 0){
tmpbuf[j-1] = sub(tmpbuf[j-1], k);
tmpbuf[j] = add(tmpbuf[j], k);
}
}
/* compute the quantized lsf vector */
Lsp_prev_compose(tmpbuf, lsfq, noise_fg[index[0]], freq_prev,
noise_fg_sum[index[0]]);
/* update the prediction memory */
Lsp_prev_update(tmpbuf, freq_prev);
/* lsf stability check */
Lsp_stability(lsfq);
/* convert lsf to lsp */
Lsf_lsp2(lsfq, lspq, M);
}
