?? acelp_co.c
字號(hào):
p1 -= ldec;
p0 -= ldec;
}
cor = L_mac(cor, *ptr_h1, *ptr_h2); ptr_h1++; ptr_h2++;
*p3 = extract_h(cor);
l_fin_sup -= NB_POS;
l_fin_inf--;
ptr_hf += STEP;
}
return;
}
/*------------------------------------------------------------------------*
* Function D4i40_17 *
* ~~~~~~~~~ *
* Algebraic codebook for ITU 8 kb/s. *
* -> 17 bits; 4 pulses in a frame of 40 samples *
* *
*------------------------------------------------------------------------*
* The code length is 40, containing 4 nonzero pulses i0, i1, i2, i3. *
* Each pulses can have 8 possible positions (positive or negative) *
* except i3 that have 16 possible positions. *
* *
* i0 (+-1) : 0, 5, 10, 15, 20, 25, 30, 35 *
* i1 (+-1) : 1, 6, 11, 16, 21, 26, 31, 36 *
* i2 (+-1) : 2, 7, 12, 17, 22, 27, 32, 37 *
* i3 (+-1) : 3, 8, 13, 18, 23, 28, 33, 38 *
* 4, 9, 14, 19, 24, 29, 34, 39 *
*------------------------------------------------------------------------*/
static Word16 extra;
static Word16 D4i40_17( /* (o) : Index of pulses positions. */
Word16 Dn[], /* (i) : Correlations between h[] and Xn[]. */
Word16 rr[], /* (i) : Correlations of impulse response h[]. */
Word16 h[], /* (i) Q12: Impulse response of filters. */
Word16 cod[], /* (o) Q13: Selected algebraic codeword. */
Word16 y[], /* (o) Q12: Filtered algebraic codeword. */
Word16 *sign, /* (o) : Signs of 4 pulses. */
Word16 i_subfr /* (i) : subframe flag */
)
{
Word16 i0, i1, i2, i3, ip0, ip1, ip2, ip3;
Word16 i, j, time;
Word16 ps0, ps1, ps2, ps3, alp, alp0;
Word32 alp1, alp2, alp3, L32;
Word16 ps3c, psc, alpha;
Word16 average, max0, max1, max2, thres;
Word32 L_temp;
Word16 *rri0i0, *rri1i1, *rri2i2, *rri3i3, *rri4i4;
Word16 *rri0i1, *rri0i2, *rri0i3, *rri0i4;
Word16 *rri1i2, *rri1i3, *rri1i4;
Word16 *rri2i3, *rri2i4;
Word16 *ptr_ri0i0, *ptr_ri1i1, *ptr_ri2i2, *ptr_ri3i3, *ptr_ri4i4;
Word16 *ptr_ri0i1, *ptr_ri0i2, *ptr_ri0i3, *ptr_ri0i4;
Word16 *ptr_ri1i2, *ptr_ri1i3, *ptr_ri1i4;
Word16 *ptr_ri2i3, *ptr_ri2i4;
Word16 p_sign[L_SUBFR];
/* Init pointers */
rri0i0 = rr;
rri1i1 = rri0i0 + NB_POS;
rri2i2 = rri1i1 + NB_POS;
rri3i3 = rri2i2 + NB_POS;
rri4i4 = rri3i3 + NB_POS;
rri0i1 = rri4i4 + NB_POS;
rri0i2 = rri0i1 + MSIZE;
rri0i3 = rri0i2 + MSIZE;
rri0i4 = rri0i3 + MSIZE;
rri1i2 = rri0i4 + MSIZE;
rri1i3 = rri1i2 + MSIZE;
rri1i4 = rri1i3 + MSIZE;
rri2i3 = rri1i4 + MSIZE;
rri2i4 = rri2i3 + MSIZE;
/*-----------------------------------------------------------------------*
* Reset max_time for 1st subframe. *
*-----------------------------------------------------------------------*/
if (i_subfr == 0){ extra = 30; }
/*-----------------------------------------------------------------------*
* Chose the sign of the impulse. *
*-----------------------------------------------------------------------*/
for (i=0; i<L_SUBFR; i++)
{
if( Dn[i] >= 0)
{
p_sign[i] = 0x7fff;
}
else
{
p_sign[i] = (Word16)0x8000;
Dn[i] = negate(Dn[i]);
}
}
/*-------------------------------------------------------------------*
* - Compute the search threshold after three pulses *
*-------------------------------------------------------------------*/
/* Find maximum of Dn[i0]+Dn[i1]+Dn[i2] */
max0 = Dn[0];
max1 = Dn[1];
max2 = Dn[2];
for (i = 5; i < L_SUBFR; i+=STEP)
{
if (sub(Dn[i] , max0) > 0){ max0 = Dn[i]; }
if (sub(Dn[i+1], max1) > 0){ max1 = Dn[i+1]; }
if (sub(Dn[i+2], max2) > 0){ max2 = Dn[i+2]; }
}
max0 = add(max0, max1);
max0 = add(max0, max2);
/* Find average of Dn[i0]+Dn[i1]+Dn[i2] */
L32 = 0;
for (i = 0; i < L_SUBFR; i+=STEP)
{
L32 = L_mac(L32, Dn[i], 1);
L32 = L_mac(L32, Dn[i+1], 1);
L32 = L_mac(L32, Dn[i+2], 1);
}
average =extract_l( L_shr(L32, 4)); /* 1/8 of sum */
/* thres = average + (max0-average)*THRESHFCB; */
thres = sub(max0, average);
thres = mult(thres, THRESHFCB);
thres = add(thres, average);
/*-------------------------------------------------------------------*
* Modification of rrixiy[] to take signs into account. *
*-------------------------------------------------------------------*/
ptr_ri0i1 = rri0i1;
ptr_ri0i2 = rri0i2;
ptr_ri0i3 = rri0i3;
ptr_ri0i4 = rri0i4;
for(i0=0; i0<L_SUBFR; i0+=STEP)
{
for(i1=1; i1<L_SUBFR; i1+=STEP)
{
*ptr_ri0i1 = mult(*ptr_ri0i1, mult(p_sign[i0], p_sign[i1]));
ptr_ri0i1++;
*ptr_ri0i2 = mult(*ptr_ri0i2, mult(p_sign[i0], p_sign[i1+1]));
ptr_ri0i2++;
*ptr_ri0i3 = mult(*ptr_ri0i3, mult(p_sign[i0], p_sign[i1+2]));
ptr_ri0i3++;
*ptr_ri0i4 = mult(*ptr_ri0i4, mult(p_sign[i0], p_sign[i1+3]));
ptr_ri0i4++;
}
}
ptr_ri1i2 = rri1i2;
ptr_ri1i3 = rri1i3;
ptr_ri1i4 = rri1i4;
for(i1=1; i1<L_SUBFR; i1+=STEP)
{
for(i2=2; i2<L_SUBFR; i2+=STEP)
{
*ptr_ri1i2 = mult(*ptr_ri1i2, mult(p_sign[i1], p_sign[i2]));
ptr_ri1i2++;
*ptr_ri1i3 = mult(*ptr_ri1i3, mult(p_sign[i1], p_sign[i2+1]));
ptr_ri1i3++;
*ptr_ri1i4 = mult(*ptr_ri1i4, mult(p_sign[i1], p_sign[i2+2]));
ptr_ri1i4++;
}
}
ptr_ri2i3 = rri2i3;
ptr_ri2i4 = rri2i4;
for(i2=2; i2<L_SUBFR; i2+=STEP)
{
for(i3=3; i3<L_SUBFR; i3+=STEP)
{
*ptr_ri2i3 = mult(*ptr_ri2i3, mult(p_sign[i2], p_sign[i3]));
ptr_ri2i3++;
*ptr_ri2i4 = mult(*ptr_ri2i4, mult(p_sign[i2], p_sign[i3+1]));
ptr_ri2i4++;
}
}
/*-------------------------------------------------------------------*
* Search the optimum positions of the four pulses which maximize *
* square(correlation) / energy *
* The search is performed in four nested loops. At each loop, one *
* pulse contribution is added to the correlation and energy. *
* *
* The fourth loop is entered only if the correlation due to the *
* contribution of the first three pulses exceeds the preset *
* threshold. *
*-------------------------------------------------------------------*/
/* Default values */
ip0 = 0;
ip1 = 1;
ip2 = 2;
ip3 = 3;
psc = 0;
alpha = MAX_16;
time = add(MAX_TIME, extra);
/* Four loops to search innovation code. */
ptr_ri0i0 = rri0i0; /* Init. pointers that depend on first loop */
ptr_ri0i1 = rri0i1;
ptr_ri0i2 = rri0i2;
ptr_ri0i3 = rri0i3;
ptr_ri0i4 = rri0i4;
for (i0 = 0; i0 < L_SUBFR; i0 += STEP) /* first pulse loop */
{
ps0 = Dn[i0];
alp0 = *ptr_ri0i0++;
ptr_ri1i1 = rri1i1; /* Init. pointers that depend on second loop */
ptr_ri1i2 = rri1i2;
ptr_ri1i3 = rri1i3;
ptr_ri1i4 = rri1i4;
for (i1 = 1; i1 < L_SUBFR; i1 += STEP) /* second pulse loop */
{
ps1 = add(ps0, Dn[i1]);
/* alp1 = alp0 + *ptr_ri1i1++ + 2.0 * ( *ptr_ri0i1++); */
alp1 = L_mult(alp0, 1);
alp1 = L_mac(alp1, *ptr_ri1i1++, 1);
alp1 = L_mac(alp1, *ptr_ri0i1++, 2);
ptr_ri2i2 = rri2i2; /* Init. pointers that depend on third loop */
ptr_ri2i3 = rri2i3;
ptr_ri2i4 = rri2i4;
for (i2 = 2; i2 < L_SUBFR; i2 += STEP) /* third pulse loop */
{
ps2 = add(ps1, Dn[i2]);
/* alp2 = alp1 + *ptr_ri2i2++ + 2.0 * (*ptr_ri0i2++ + *ptr_ri1i2++); */
alp2 = L_mac(alp1, *ptr_ri2i2++, 1);
alp2 = L_mac(alp2, *ptr_ri0i2++, 2);
alp2 = L_mac(alp2, *ptr_ri1i2++, 2);
/* Test threshold */
if ( sub(ps2, thres) > 0)
{
ptr_ri3i3 = rri3i3; /* Init. pointers that depend on 4th loop */
for (i3 = 3; i3 < L_SUBFR; i3 += STEP) /* 4th pulse loop */
{
ps3 = add(ps2, Dn[i3]);
/* alp3 = alp2 + *ptr_ri3i3++ */
/* + 2.0*( *ptr_ri0i3++ + *ptr_ri1i3++ + *ptr_ri2i3++); */
alp3 = L_mac(alp2, *ptr_ri3i3++, 1);
alp3 = L_mac(alp3, *ptr_ri0i3++, 2);
alp3 = L_mac(alp3, *ptr_ri1i3++, 2);
alp3 = L_mac(alp3, *ptr_ri2i3++, 2);
alp = extract_l(L_shr(alp3, 5));
ps3c = mult(ps3, ps3);
L_temp = L_mult(ps3c, alpha);
L_temp = L_msu(L_temp, psc, alp);
if( L_temp > 0L )
{
psc = ps3c;
alpha = alp;
ip0 = i0;
ip1 = i1;
ip2 = i2;
ip3 = i3;
}
} /* end of for i3 = */
ptr_ri0i3 -= NB_POS;
ptr_ri1i3 -= NB_POS;
ptr_ri4i4 = rri4i4; /* Init. pointers that depend on 4th loop */
for (i3 = 4; i3 < L_SUBFR; i3 += STEP) /* 4th pulse loop */
{
ps3 = add(ps2, Dn[i3]);
/* alp3 = alp2 + *ptr_ri4i4++ */
/* + 2.0*( *ptr_ri0i4++ + *ptr_ri1i4++ + *ptr_ri2i4++); */
alp3 = L_mac(alp2, *ptr_ri4i4++, 1);
alp3 = L_mac(alp3, *ptr_ri0i4++, 2);
alp3 = L_mac(alp3, *ptr_ri1i4++, 2);
alp3 = L_mac(alp3, *ptr_ri2i4++, 2);
alp = extract_l(L_shr(alp3, 5));
ps3c = mult(ps3, ps3);
L_temp = L_mult(ps3c, alpha);
L_temp = L_msu(L_temp, psc, alp);
if( L_temp > 0L )
{
psc = ps3c;
alpha = alp;
ip0 = i0;
ip1 = i1;
ip2 = i2;
ip3 = i3;
}
} /* end of for i3 = */
ptr_ri0i4 -= NB_POS;
ptr_ri1i4 -= NB_POS;
time = sub(time, 1);
if(time <= 0 ) goto end_search; /* Maximum time finish */
} /* end of if >thres */
else
{
ptr_ri2i3 += NB_POS;
ptr_ri2i4 += NB_POS;
}
} /* end of for i2 = */
ptr_ri0i2 -= NB_POS;
ptr_ri1i3 += NB_POS;
ptr_ri1i4 += NB_POS;
} /* end of for i1 = */
ptr_ri0i2 += NB_POS;
ptr_ri0i3 += NB_POS;
ptr_ri0i4 += NB_POS;
} /* end of for i0 = */
end_search:
extra = time;
/* Set the sign of impulses */
i0 = p_sign[ip0];
i1 = p_sign[ip1];
i2 = p_sign[ip2];
i3 = p_sign[ip3];
/* Find the codeword corresponding to the selected positions */
for(i=0; i<L_SUBFR; i++) {cod[i] = 0; }
cod[ip0] = shr(i0, 2); /* From Q15 to Q13 */
cod[ip1] = shr(i1, 2);
cod[ip2] = shr(i2, 2);
cod[ip3] = shr(i3, 2);
/* find the filtered codeword */
for (i = 0; i < L_SUBFR; i++) {y[i] = 0; }
if(i0 > 0)
for(i=ip0, j=0; i<L_SUBFR; i++, j++) {
y[i] = add(y[i], h[j]); }
else
for(i=ip0, j=0; i<L_SUBFR; i++, j++) {
y[i] = sub(y[i], h[j]); }
if(i1 > 0)
for(i=ip1, j=0; i<L_SUBFR; i++, j++) {
y[i] = add(y[i], h[j]); }
else
for(i=ip1, j=0; i<L_SUBFR; i++, j++) {
y[i] = sub(y[i], h[j]); }
if(i2 > 0)
for(i=ip2, j=0; i<L_SUBFR; i++, j++) {
y[i] = add(y[i], h[j]); }
else
for(i=ip2, j=0; i<L_SUBFR; i++, j++) {
y[i] = sub(y[i], h[j]); }
if(i3 > 0)
for(i=ip3, j=0; i<L_SUBFR; i++, j++) {
y[i] = add(y[i], h[j]); }
else
for(i=ip3, j=0; i<L_SUBFR; i++, j++) {
y[i] = sub(y[i], h[j]); }
/* find codebook index; 17-bit address */
i = 0;
if(i0 > 0) i = add(i, 1);
if(i1 > 0) i = add(i, 2);
if(i2 > 0) i = add(i, 4);
if(i3 > 0) i = add(i, 8);
*sign = i;
ip0 = mult(ip0, 6554); /* ip0/5 */
ip1 = mult(ip1, 6554); /* ip1/5 */
ip2 = mult(ip2, 6554); /* ip2/5 */
i = mult(ip3, 6554); /* ip3/5 */
j = add(i, shl(i, 2)); /* j = i*5 */
j = sub(ip3, add(j, 3)); /* j= ip3%5 -3 */
ip3 = add(shl(i, 1), j);
i = add(ip0, shl(ip1, 3));
i = add(i , shl(ip2, 6));
i = add(i , shl(ip3, 9));
return i;
}
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