r_uquant.c

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#include "sr_lpc10.h"
#include <math.h>

/**********************************************************/

static INDEX G_detab7[32] = {
    4, 11, 18, 25, 32, 39, 46, 53, 60, 66, 72, 77, 82, 87, 92, 96, 101,
    104, 108, 111, 114, 115, 117, 119, 121, 122, 123, 124, 125, 126,
    127, 127
};

#define F FLOAT
static FLOAT G_descl[8] = {
    (F).6953, (F).6250, (F).5781, (F).5469, 
    (F).5312, (F).5391, (F).4688, (F).3828
};

static FLOAT G_deadd[8] = {
    (F)1152, (F)-2816, (F)-1536, (F)-3584, 
    (F)-1280, (F)-2432, (F)768, (F)-1920
};
#undef F

static INDEX G_qb[8] = {
    511, 511, 1023, 1023, 1023, 1023, 2047, 4095
};

static INDEX G_nbit[10] = {
    6, 6, 9, 9, 10, 10, 10, 10, 11, 12
};

/**********************************************************/

VOID unquant ( INDEX itab[13], BOOL voice[2],
        INT * pitch, FLOAT * rms, FLOAT rc[ORDER])
{
#define SCALERC (FLOAT)6.103515625e-05  /* 16,384 = 2**14 */
    INDEX i;
#ifdef NEGTRUNC
    FLOAT ftemp;
    INDEX itemp;
#endif

    /* pitch and voicing decision */
    *pitch = ITAB13_IPITCH;
    voice[1] = (ITAB13_IVOICE & 0x01);
    voice[0] = (ITAB13_IVOICE > 1);

    /* Decode RMS */
    *rms = (FLOAT)(G_rmst[(31 - ITAB13_IRMS) * 2]);

    /* Decode RC(1) and RC(2) from log-area-ratios */
    for (i = 0; i <= 1; i++) {
        INDEX i2 = ITAB13_IRC(i);
        if (i2 < 0)
            i2 = -G_detab7[2 * (-i2)];
        else
            i2 = G_detab7[2 * i2];
        rc[i] = (i2 * (2 << G_nbit[i])) * SCALERC;
    }

    /* Decode RC(3)-RC(10) to sign plus 14 bits */
    for (i = 2; i < ORDER; i++) {
        INDEX i2 = ITAB13_IRC(i);
        i2 *= (2 << G_nbit[i]);
        i2 += G_qb[i - 2];
#ifdef NEGTRUNC
        ftemp = i2 * G_descl[i-2] + G_deadd[i-2]; /* rounding problem */
        if (ftemp < 0) {
            ftemp = -ftemp;
            itemp = ftemp;
            rc[i] = (-itemp) * SCALERC;
        }
        else
            rc[i] = (INDEX)ftemp * SCALERC;
#else
        rc[i] = (INDEX)(i2 * G_descl[i-2] + G_deadd[i-2]) * SCALERC;
#endif
    }
}

/**********************************************************/

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