package org.mobicents.media.server.impl.dsp.audio.g729;
public class DecAcelp {
/*-----------------------------------------------------------*
* Function decod_ACELP() *
* ~~~~~~~~~~~~~~~~~~~~~~~ *
* Algebraic codebook decoder. *
*----------------------------------------------------------*/
public static void decod_ACELP(
int sign, /* input : signs of 4 pulses */
int index, /* input : positions of 4 pulses */
float cod[] /* output: innovative codevector */
)
{
int pos[] = new int[4];
int i, j;
/* decode the positions of 4 pulses */
i = index & 7;
pos[0] = i*5;
index >>= 3;
i = index & 7;
pos[1] = i*5 + 1;
index >>= 3;
i = index & 7;
pos[2] = i*5 + 2;
index >>= 3;
j = index & 1;
index >>= 1;
i = index & 7;
pos[3] = i*5 + 3 + j;
/* find the algebraic codeword */
for (i = 0; i < LD8KConstants.L_SUBFR; i++) cod[i] = 0;
/* decode the signs of 4 pulses */
for (j=0; j<4; j++)
{
i = sign & 1;
sign >>= 1;
if (i != 0) {
cod[pos[j]] = (float)1.0;
}
else {
cod[pos[j]] = (float)-1.0;
}
}
return;
}
}