contrib/src/mmedia/g72x.cpp

/*
 * This source code is a product of Sun Microsystems, Inc. and is provided
 * for unrestricted use.  Users may copy or modify this source code without
 * charge.
 *
 * SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
 * THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
 *
 * Sun source code is provided with no support and without any obligation on
 * the part of Sun Microsystems, Inc. to assist in its use, correction,
 * modification or enhancement.
 *
 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
 * OR ANY PART THEREOF.
 *
 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
 * or profits or other special, indirect and consequential damages, even if
 * Sun has been advised of the possibility of such damages.
 *
 * Sun Microsystems, Inc.
 * 2550 Garcia Avenue
 * Mountain View, California  94043
 */

/*
 * g72x.c
 *
 * Common routines for G.721 and G.723 conversions.
 */

#include "wx/wxprec.h"
#include <stdlib.h>
#include "wx/mmedia/internal/g72x.h"

static short power2[15] = {1, 2, 4, 8, 0x10, 0x20, 0x40, 0x80,
            0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000};

/*
 * quan()
 *
 * quantizes the input val against the table of size short integers.
 * It returns i if table[i - 1] <= val < table[i].
 *
 * Using linear search for simple coding.
 */
static int
quan(
    int           val,
    short        *table,
    int           size)
{
    int i;

    for (i = 0; i < size; i++)
        if (val < *table++)
            break;
    return (i);
}

static char quan2_tab[65536];
static short base2_tab[65536];
static int init_tabs_done = 0;

inline char quan2 (unsigned short val)
{
    return quan2_tab[val];
}

inline short base2 (unsigned short val)
{
    return base2_tab[val];
}

static void init_quan2_tab (void)
{
    long i;

    for (i = 0; i < 65536; i++) {
        quan2_tab[i] = quan (i, power2, 15);
    };
}

static void init_base2_tab (void)
{
    long i;
    short exp;

    for (i = 0; i < 65536; i++) {
        exp = quan2 (short (i));
        base2_tab[i] = short ((exp << 6) + ((i << 6) >> exp));
    };
}

static void init_tabs (void)
{
    if (init_tabs_done) return;

    init_quan2_tab();
    init_base2_tab();

    init_tabs_done = 1;
}

/*
 * fmult()
 *
 * returns the integer product of the 14-bit integer "an" and
 * "floating point" representation (4-bit exponent, 6-bit mantessa) "srn".
 */
static int
fmult(
    int        an,
    int        srn)
{
    short        anmag, anexp, anmant;
    short        wanexp, wanmant;
    short        retval;

    anmag = (an > 0) ? an : ((-an) & 0x1FFF);
    anexp = quan2(anmag) - 6;
    anmant = (anmag == 0) ? 32 :
        (anexp >= 0) ? anmag >> anexp : anmag << -anexp;
    wanexp = anexp + ((srn >> 6) & 0xF) - 13;

    wanmant = (anmant * (srn & 077) + 0x30) >> 4;
    retval = (wanexp >= 0) ? ((wanmant << wanexp) & 0x7FFF) :
        (wanmant >> -wanexp);

    return (((an ^ srn) < 0) ? -retval : retval);
}

/*
 * g72x_init_state()
 *
 * This routine initializes and/or resets the g72x_state structure
 * pointed to by 'state_ptr'.
 * All the initial state values are specified in the CCITT G.721 document.
 */
void
g72x_init_state(
    struct g72x_state *state_ptr)
{
    int cnta;

    init_tabs ();

    state_ptr->yl = 34816;
    state_ptr->yu = 544;
    state_ptr->dms = 0;
    state_ptr->dml = 0;
    state_ptr->ap = 0;
    for (cnta = 0; cnta < 2; cnta++) {
        state_ptr->a[cnta] = 0;
        state_ptr->pk[cnta] = 0;
        state_ptr->sr[cnta] = 32;
    }
    for (cnta = 0; cnta < 6; cnta++) {
        state_ptr->b[cnta] = 0;
        state_ptr->dq[cnta] = 32;
    }
    state_ptr->td = 0;
}

/*
 * predictor_zero()
 *
 * computes the estimated signal from 6-zero predictor.
 *
 */
int
predictor_zero(
    struct g72x_state *state_ptr)
{
    int        i;
    int        sezi;

    sezi = fmult(state_ptr->b[0] >> 2, state_ptr->dq[0]);
    for (i = 1; i < 6; i++)            /* ACCUM */
        sezi += fmult(state_ptr->b[i] >> 2, state_ptr->dq[i]);
    return (sezi);
}
/*
 * predictor_pole()
 *
 * computes the estimated signal from 2-pole predictor.
 *
 */
int
predictor_pole(
    struct g72x_state *state_ptr)
{
    return (fmult(state_ptr->a[1] >> 2, state_ptr->sr[1]) +
        fmult(state_ptr->a[0] >> 2, state_ptr->sr[0]));
}
/*
 * step_size()
 *
 * computes the quantization step size of the adaptive quantizer.
 *
 */
int
step_size(
    struct g72x_state *state_ptr)
{
    int        y;
    int        dif;
    int        al;

    if (state_ptr->ap >= 256)
        return (state_ptr->yu);
    else {
        y = state_ptr->yl >> 6;
        dif = state_ptr->yu - y;
        al = state_ptr->ap >> 2;
        if (dif > 0)
            y += (dif * al) >> 6;
        else if (dif < 0)
            y += (dif * al + 0x3F) >> 6;
        return (y);
    }
}

/*
 * quantize()
 *
 * Given a raw sample, 'd', of the difference signal and a
 * quantization step size scale factor, 'y', this routine returns the
 * ADPCM codeword to which that sample gets quantized.  The step
 * size scale factor division operation is done in the log base 2 domain
 * as a subtraction.
 */
int
quantize(
    int        d,        /* Raw difference signal sample */
    int        y,        /* Step size multiplier */
    short     *table,    /* quantization table */
    int        size)     /* table size of short integers */
{
    short        dqm;    /* Magnitude of 'd' */
    short        exp;    /* Integer part of base 2 log of 'd' */
    short        mant;   /* Fractional part of base 2 log */
    short        dl;     /* Log of magnitude of 'd' */
    short        dln;    /* Step size scale factor normalized log */
    int          i;

    /*
     * LOG
     *
     * Compute base 2 log of 'd', and store in 'dl'.
     */
    dqm = abs(d);
    exp = quan2(dqm >> 1);
    mant = ((dqm << 7) >> exp) & 0x7F;    /* Fractional portion. */
    dl = (exp << 7) + mant;

    /*
     * SUBTB
     *
     * "Divide" by step size multiplier.
     */
    dln = dl - (y >> 2);

    /*
     * QUAN
     *
     * Obtain codword i for 'd'.
     */
    i = quan(dln, table, size);
    if (d < 0)            /* take 1's complement of i */
        return ((size << 1) + 1 - i);
    else if (i == 0)        /* take 1's complement of 0 */
        return ((size << 1) + 1); /* new in 1988 */
    else
        return (i);
}
/*
 * reconstruct()
 *
 * Returns reconstructed difference signal 'dq' obtained from
 * codeword 'i' and quantization step size scale factor 'y'.
 * Multiplication is performed in log base 2 domain as addition.
 */
int
reconstruct(
    int        sign,    /* 0 for non-negative value */
    int        dqln,    /* G.72x codeword */
    int        y)       /* Step size multiplier */
{
    short        dql;   /* Log of 'dq' magnitude */
    short        dex;   /* Integer part of log */
    short        dqt;
    short        dq;    /* Reconstructed difference signal sample */

    dql = dqln + (y >> 2);    /* ADDA */

    if (dql < 0) {
        return ((sign) ? -0x8000 : 0);
    } else {        /* ANTILOG */
        dex = (dql >> 7) & 15;
        dqt = 128 + (dql & 127);
        dq = (dqt << 7) >> (14 - dex);
        return ((sign) ? (dq - 0x8000) : dq);
    }
}


/*
 * update()
 *
 * updates the state variables for each output code
 */
void
update(
    int        code_size,    /* distinguish 723_40 with others */
    int        y,            /* quantizer step size */
    int        wi,           /* scale factor multiplier */
    int        fi,           /* for long/short term energies */
    int        dq,           /* quantized prediction difference */
    int        sr,           /* reconstructed signal */
    int        dqsez,        /* difference from 2-pole predictor */
    struct g72x_state *state_ptr)    /* coder state pointer */
{
    int          cnt;
    short        mag;        /* Adaptive predictor, FLOAT A */
    short        a2p;        /* LIMC */
    short        a1ul;       /* UPA1 */
    short        pks1;       /* UPA2 */
    short        fa1;
    char         tr;         /* tone/transition detector */
    short        ylint, thr2, dqthr;
    short        ylfrac, thr1;
    short        pk0;

    pk0 = (dqsez < 0) ? 1 : 0;    /* needed in updating predictor poles */

    mag = dq & 0x7FFF;        /* prediction difference magnitude */
    /* TRANS */
    ylint = short (state_ptr->yl >> 15);    /* exponent part of yl */
    ylfrac = (state_ptr->yl >> 10) & 0x1F;    /* fractional part of yl */
    thr1 = (32 + ylfrac) << ylint;        /* threshold */
    thr2 = (ylint > 9) ? 31 << 10 : thr1;    /* limit thr2 to 31 << 10 */
    dqthr = (thr2 + (thr2 >> 1)) >> 1;    /* dqthr = 0.75 * thr2 */
    if (state_ptr->td == 0)        /* signal supposed voice */
        tr = 0;
    else if (mag <= dqthr)        /* supposed data, but small mag */
        tr = 0;            /* treated as voice */
    else                /* signal is data (modem) */
        tr = 1;

    /*
     * Quantizer scale factor adaptation.
     */

    /* FUNCTW & FILTD & DELAY */
    /* update non-steady state step size multiplier */
    state_ptr->yu = y + ((wi - y) >> 5);

    /* LIMB */
    if (state_ptr->yu < 544)    /* 544 <= yu <= 5120 */
        state_ptr->yu = 544;
    else if (state_ptr->yu > 5120)
        state_ptr->yu = 5120;

    /* FILTE & DELAY */
    /* update steady state step size multiplier */
    state_ptr->yl += state_ptr->yu + ((-state_ptr->yl) >> 6);

    /*
     * Adaptive predictor coefficients.
     */
    if (tr == 1) {            /* reset a's and b's for modem signal */
        state_ptr->a[0] = 0;
        state_ptr->a[1] = 0;
        state_ptr->b[0] = 0;
        state_ptr->b[1] = 0;
        state_ptr->b[2] = 0;
        state_ptr->b[3] = 0;
        state_ptr->b[4] = 0;
        state_ptr->b[5] = 0;

        a2p = 0;        /* eliminate Compiler Warnings */
    } else {            /* update a's and b's */
        pks1 = pk0 ^ state_ptr->pk[0];        /* UPA2 */

        /* update predictor pole a[1] */
        a2p = state_ptr->a[1] - (state_ptr->a[1] >> 7);
        if (dqsez != 0) {
            fa1 = (pks1) ? state_ptr->a[0] : -state_ptr->a[0];
            if (fa1 < -8191)    /* a2p = function of fa1 */
                a2p -= 0x100;
            else if (fa1 > 8191)
                a2p += 0xFF;
            else
                a2p += fa1 >> 5;

            if (pk0 ^ state_ptr->pk[1])
                /* LIMC */
                if (a2p <= -12160)
                    a2p = -12288;
                else if (a2p >= 12416)
                    a2p = 12288;
                else
                    a2p -= 0x80;
            else if (a2p <= -12416)
                a2p = -12288;
            else if (a2p >= 12160)
                a2p = 12288;
            else
                a2p += 0x80;
        }

        /* TRIGB & DELAY */
        state_ptr->a[1] = a2p;

        /* UPA1 */
        /* update predictor pole a[0] */
        state_ptr->a[0] -= state_ptr->a[0] >> 8;
        if (dqsez != 0)
            if (pks1 == 0)
                state_ptr->a[0] += 192;
            else
                state_ptr->a[0] -= 192;

        /* LIMD */
        a1ul = 15360 - a2p;
        if (state_ptr->a[0] < -a1ul)
            state_ptr->a[0] = -a1ul;
        else if (state_ptr->a[0] > a1ul)
            state_ptr->a[0] = a1ul;

        /* UPB : update predictor zeros b[6] */
        for (cnt = 0; cnt < 6; cnt++) {
            if (code_size == 5)        /* for 40Kbps G.723 */
                state_ptr->b[cnt] -= state_ptr->b[cnt] >> 9;
            else            /* for G.721 and 24Kbps G.723 */
                state_ptr->b[cnt] -= state_ptr->b[cnt] >> 8;
            if (dq & 0x7FFF) {            /* XOR */
                if ((dq ^ state_ptr->dq[cnt]) >= 0)
                    state_ptr->b[cnt] += 128;
                else
                    state_ptr->b[cnt] -= 128;
            }
        }
    }

    for (cnt = 5; cnt > 0; cnt--)
        state_ptr->dq[cnt] = state_ptr->dq[cnt-1];
    /* FLOAT A : convert dq[0] to 4-bit exp, 6-bit mantissa f.p. */
    if (mag == 0) {
        state_ptr->dq[0] = (dq >= 0) ? 0x20 : 0xFC20;
    } else {
        state_ptr->dq[0] = (dq >= 0) ?
             base2 (mag) : base2 (mag) - 0x400;
    }

    state_ptr->sr[1] = state_ptr->sr[0];
    /* FLOAT B : convert sr to 4-bit exp., 6-bit mantissa f.p. */
    if (sr == 0) {
        state_ptr->sr[0] = 0x20;
    } else if (sr > 0) {
        state_ptr->sr[0] = base2(sr);
    } else if (sr > -32768) {
        mag = -sr;
        state_ptr->sr[0] = base2(mag) - 0x400;
    } else {
        const unsigned short c = 0xFC20;
        state_ptr->sr[0] = short(c);
    }

    /* DELAY A */
    state_ptr->pk[1] = state_ptr->pk[0];
    state_ptr->pk[0] = pk0;

    /* TONE */
    if (tr == 1)        /* this sample has been treated as data */
        state_ptr->td = 0;    /* next one will be treated as voice */
    else if (a2p < -11776)    /* small sample-to-sample correlation */
        state_ptr->td = 1;    /* signal may be data */
    else                      /* signal is voice */
        state_ptr->td = 0;

    /*
     * Adaptation speed control.
     */
    state_ptr->dms += (fi - state_ptr->dms) >> 5;        /* FILTA */
    state_ptr->dml += (((fi << 2) - state_ptr->dml) >> 7);    /* FILTB */

    if (tr == 1)
        state_ptr->ap = 256;
    else if (y < 1536)                    /* SUBTC */
        state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
    else if (state_ptr->td == 1)
        state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
    else if (abs((state_ptr->dms << 2) - state_ptr->dml) >=
        (state_ptr->dml >> 3))
        state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
    else
        state_ptr->ap += (-state_ptr->ap) >> 4;
}

/*
 * tandem_adjust(sr, se, y, i, sign)
 *
 * At the end of ADPCM decoding, it simulates an encoder which may be receiving
 * the output of this decoder as a tandem process. If the output of the
 * simulated encoder differs from the input to this decoder, the decoder output
 * is adjusted by one level of A-law or u-law codes.
 *
 * Input:
 *    sr    decoder output linear PCM sample,
 *    se    predictor estimate sample,
 *    y     quantizer step size,
 *    i     decoder input code,
 *    sign  sign bit of code i
 *
 * Return:
 *    adjusted A-law or u-law compressed sample.
 */
int
tandem_adjust_alaw(
    int        sr,    /* decoder output linear PCM sample */
    int        se,    /* predictor estimate sample */
    int        y,     /* quantizer step size */
    int        i,     /* decoder input code */
    int        sign,
    short     *qtab)
{
    unsigned char    sp;    /* A-law compressed 8-bit code */
    short            dx;    /* prediction error */
    char             id;    /* quantized prediction error */
    int              sd;    /* adjusted A-law decoded sample value */
    int              im;    /* biased magnitude of i */
    int              imx;   /* biased magnitude of id */

    if (sr <= -32768)
        sr = -1;
    sp = linear2alaw((sr >> 1) << 3);    /* short to A-law compression */
    dx = (alaw2linear(sp) >> 2) - se;    /* 16-bit prediction error */
    id = quantize(dx, y, qtab, sign - 1);

    if (id == i) {            /* no adjustment on sp */
        return (sp);
    } else {            /* sp adjustment needed */
        /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */
        im = i ^ sign;        /* 2's complement to biased unsigned */
        imx = id ^ sign;

        if (imx > im) {        /* sp adjusted to next lower value */
            if (sp & 0x80) {
                sd = (sp == 0xD5) ? 0x55 :
                    ((sp ^ 0x55) - 1) ^ 0x55;
            } else {
                sd = (sp == 0x2A) ? 0x2A :
                    ((sp ^ 0x55) + 1) ^ 0x55;
            }
        } else {        /* sp adjusted to next higher value */
            if (sp & 0x80)
                sd = (sp == 0xAA) ? 0xAA :
                    ((sp ^ 0x55) + 1) ^ 0x55;
            else
                sd = (sp == 0x55) ? 0xD5 :
                    ((sp ^ 0x55) - 1) ^ 0x55;
        }
        return (sd);
    }
}

int
tandem_adjust_ulaw(
    int        sr,    /* decoder output linear PCM sample */
    int        se,    /* predictor estimate sample */
    int        y,    /* quantizer step size */
    int        i,    /* decoder input code */
    int        sign,
    short     *qtab)
{
    unsigned char    sp;    /* u-law compressed 8-bit code */
    short            dx;    /* prediction error */
    char             id;    /* quantized prediction error */
    int              sd;    /* adjusted u-law decoded sample value */
    int              im;    /* biased magnitude of i */
    int              imx;   /* biased magnitude of id */

    if (sr <= -32768)
        sr = 0;
    sp = linear2ulaw(sr << 2);    /* short to u-law compression */
    dx = (ulaw2linear(sp) >> 2) - se;    /* 16-bit prediction error */
    id = quantize(dx, y, qtab, sign - 1);
    if (id == i) {
        return (sp);
    } else {
        /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */
        im = i ^ sign;        /* 2's complement to biased unsigned */
        imx = id ^ sign;
        if (imx > im) {        /* sp adjusted to next lower value */
            if (sp & 0x80)
                sd = (sp == 0xFF) ? 0x7E : sp + 1;
            else
                sd = (sp == 0) ? 0 : sp - 1;

        } else {        /* sp adjusted to next higher value */
            if (sp & 0x80)
                sd = (sp == 0x80) ? 0x80 : sp - 1;
            else
                sd = (sp == 0x7F) ? 0xFE : sp + 1;
        }
        return (sd);
    }
}
Commit	Line	Data
	1	/*
	2	* This source code is a product of Sun Microsystems, Inc. and is provided
	3	* for unrestricted use. Users may copy or modify this source code without
	4	* charge.
	5	*
	6	* SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
	7	* THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
	8	* PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
	9	*
	10	* Sun source code is provided with no support and without any obligation on
	11	* the part of Sun Microsystems, Inc. to assist in its use, correction,
	12	* modification or enhancement.
	13	*
	14	* SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
	15	* INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
	16	* OR ANY PART THEREOF.
	17	*
	18	* In no event will Sun Microsystems, Inc. be liable for any lost revenue
	19	* or profits or other special, indirect and consequential damages, even if
	20	* Sun has been advised of the possibility of such damages.
	21	*
	22	* Sun Microsystems, Inc.
	23	* 2550 Garcia Avenue
	24	* Mountain View, California 94043
	25	*/
	26
	27	/*
	28	* g72x.c
	29	*
	30	* Common routines for G.721 and G.723 conversions.
	31	*/
	32
	33	#include "wx/wxprec.h"
	34	#include <stdlib.h>
	35	#include "wx/mmedia/internal/g72x.h"
	36
	37	static short power2[15] = {1, 2, 4, 8, 0x10, 0x20, 0x40, 0x80,
	38	0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000};
	39
	40	/*
	41	* quan()
	42	*
	43	* quantizes the input val against the table of size short integers.
	44	* It returns i if table[i - 1] <= val < table[i].
	45	*
	46	* Using linear search for simple coding.
	47	*/
	48	static int
	49	quan(
	50	int val,
	51	short *table,
	52	int size)
	53	{
	54	int i;
	55
	56	for (i = 0; i < size; i++)
	57	if (val < *table++)
	58	break;
	59	return (i);
	60	}
	61
	62	static char quan2_tab[65536];
	63	static short base2_tab[65536];
	64	static int init_tabs_done = 0;
	65
	66	inline char quan2 (unsigned short val)
	67	{
	68	return quan2_tab[val];
	69	}
	70
	71	inline short base2 (unsigned short val)
	72	{
	73	return base2_tab[val];
	74	}
	75
	76	static void init_quan2_tab (void)
	77	{
	78	long i;
	79
	80	for (i = 0; i < 65536; i++) {
	81	quan2_tab[i] = quan (i, power2, 15);
	82	};
	83	}
	84
	85	static void init_base2_tab (void)
	86	{
	87	long i;
	88	short exp;
	89
	90	for (i = 0; i < 65536; i++) {
	91	exp = quan2 (short (i));
	92	base2_tab[i] = short ((exp << 6) + ((i << 6) >> exp));
	93	};
	94	}
	95
	96	static void init_tabs (void)
	97	{
	98	if (init_tabs_done) return;
	99
	100	init_quan2_tab();
	101	init_base2_tab();
	102
	103	init_tabs_done = 1;
	104	}
	105
	106	/*
	107	* fmult()
	108	*
	109	* returns the integer product of the 14-bit integer "an" and
	110	* "floating point" representation (4-bit exponent, 6-bit mantessa) "srn".
	111	*/
	112	static int
	113	fmult(
	114	int an,
	115	int srn)
	116	{
	117	short anmag, anexp, anmant;
	118	short wanexp, wanmant;
	119	short retval;
	120
	121	anmag = (an > 0) ? an : ((-an) & 0x1FFF);
	122	anexp = quan2(anmag) - 6;
	123	anmant = (anmag == 0) ? 32 :
	124	(anexp >= 0) ? anmag >> anexp : anmag << -anexp;
	125	wanexp = anexp + ((srn >> 6) & 0xF) - 13;
	126
	127	wanmant = (anmant * (srn & 077) + 0x30) >> 4;
	128	retval = (wanexp >= 0) ? ((wanmant << wanexp) & 0x7FFF) :
	129	(wanmant >> -wanexp);
	130
	131	return (((an ^ srn) < 0) ? -retval : retval);
	132	}
	133
	134	/*
	135	* g72x_init_state()
	136	*
	137	* This routine initializes and/or resets the g72x_state structure
	138	* pointed to by 'state_ptr'.
	139	* All the initial state values are specified in the CCITT G.721 document.
	140	*/
	141	void
	142	g72x_init_state(
	143	struct g72x_state *state_ptr)
	144	{
	145	int cnta;
	146
	147	init_tabs ();
	148
	149	state_ptr->yl = 34816;
	150	state_ptr->yu = 544;
	151	state_ptr->dms = 0;
	152	state_ptr->dml = 0;
	153	state_ptr->ap = 0;
	154	for (cnta = 0; cnta < 2; cnta++) {
	155	state_ptr->a[cnta] = 0;
	156	state_ptr->pk[cnta] = 0;
	157	state_ptr->sr[cnta] = 32;
	158	}
	159	for (cnta = 0; cnta < 6; cnta++) {
	160	state_ptr->b[cnta] = 0;
	161	state_ptr->dq[cnta] = 32;
	162	}
	163	state_ptr->td = 0;
	164	}
	165
	166	/*
	167	* predictor_zero()
	168	*
	169	* computes the estimated signal from 6-zero predictor.
	170	*
	171	*/
	172	int
	173	predictor_zero(
	174	struct g72x_state *state_ptr)
	175	{
	176	int i;
	177	int sezi;
	178
	179	sezi = fmult(state_ptr->b[0] >> 2, state_ptr->dq[0]);
	180	for (i = 1; i < 6; i++) /* ACCUM */
	181	sezi += fmult(state_ptr->b[i] >> 2, state_ptr->dq[i]);
	182	return (sezi);
	183	}
	184	/*
	185	* predictor_pole()
	186	*
	187	* computes the estimated signal from 2-pole predictor.
	188	*
	189	*/
	190	int
	191	predictor_pole(
	192	struct g72x_state *state_ptr)
	193	{
	194	return (fmult(state_ptr->a[1] >> 2, state_ptr->sr[1]) +
	195	fmult(state_ptr->a[0] >> 2, state_ptr->sr[0]));
	196	}
	197	/*
	198	* step_size()
	199	*
	200	* computes the quantization step size of the adaptive quantizer.
	201	*
	202	*/
	203	int
	204	step_size(
	205	struct g72x_state *state_ptr)
	206	{
	207	int y;
	208	int dif;
	209	int al;
	210
	211	if (state_ptr->ap >= 256)
	212	return (state_ptr->yu);
	213	else {
	214	y = state_ptr->yl >> 6;
	215	dif = state_ptr->yu - y;
	216	al = state_ptr->ap >> 2;
	217	if (dif > 0)
	218	y += (dif * al) >> 6;
	219	else if (dif < 0)
	220	y += (dif * al + 0x3F) >> 6;
	221	return (y);
	222	}
	223	}
	224
	225	/*
	226	* quantize()
	227	*
	228	* Given a raw sample, 'd', of the difference signal and a
	229	* quantization step size scale factor, 'y', this routine returns the
	230	* ADPCM codeword to which that sample gets quantized. The step
	231	* size scale factor division operation is done in the log base 2 domain
	232	* as a subtraction.
	233	*/
	234	int
	235	quantize(
	236	int d, /* Raw difference signal sample */
	237	int y, /* Step size multiplier */
	238	short table, / quantization table */
	239	int size) /* table size of short integers */
	240	{
	241	short dqm; /* Magnitude of 'd' */
	242	short exp; /* Integer part of base 2 log of 'd' */
	243	short mant; /* Fractional part of base 2 log */
	244	short dl; /* Log of magnitude of 'd' */
	245	short dln; /* Step size scale factor normalized log */
	246	int i;
	247
	248	/*
	249	* LOG
	250	*
	251	* Compute base 2 log of 'd', and store in 'dl'.
	252	*/
	253	dqm = abs(d);
	254	exp = quan2(dqm >> 1);
	255	mant = ((dqm << 7) >> exp) & 0x7F; /* Fractional portion. */
	256	dl = (exp << 7) + mant;
	257
	258	/*
	259	* SUBTB
	260	*
	261	* "Divide" by step size multiplier.
	262	*/
	263	dln = dl - (y >> 2);
	264
	265	/*
	266	* QUAN
	267	*
	268	* Obtain codword i for 'd'.
	269	*/
	270	i = quan(dln, table, size);
	271	if (d < 0) /* take 1's complement of i */
	272	return ((size << 1) + 1 - i);
	273	else if (i == 0) /* take 1's complement of 0 */
	274	return ((size << 1) + 1); /* new in 1988 */
	275	else
	276	return (i);
	277	}
	278	/*
	279	* reconstruct()
	280	*
	281	* Returns reconstructed difference signal 'dq' obtained from
	282	* codeword 'i' and quantization step size scale factor 'y'.
	283	* Multiplication is performed in log base 2 domain as addition.
	284	*/
	285	int
	286	reconstruct(
	287	int sign, /* 0 for non-negative value */
	288	int dqln, /* G.72x codeword */
	289	int y) /* Step size multiplier */
	290	{
	291	short dql; /* Log of 'dq' magnitude */
	292	short dex; /* Integer part of log */
	293	short dqt;
	294	short dq; /* Reconstructed difference signal sample */
	295
	296	dql = dqln + (y >> 2); /* ADDA */
	297
	298	if (dql < 0) {
	299	return ((sign) ? -0x8000 : 0);
	300	} else { /* ANTILOG */
	301	dex = (dql >> 7) & 15;
	302	dqt = 128 + (dql & 127);
	303	dq = (dqt << 7) >> (14 - dex);
	304	return ((sign) ? (dq - 0x8000) : dq);
	305	}
	306	}
	307
	308
	309	/*
	310	* update()
	311	*
	312	* updates the state variables for each output code
	313	*/
	314	void
	315	update(
	316	int code_size, /* distinguish 723_40 with others */
	317	int y, /* quantizer step size */
	318	int wi, /* scale factor multiplier */
	319	int fi, /* for long/short term energies */
	320	int dq, /* quantized prediction difference */
	321	int sr, /* reconstructed signal */
	322	int dqsez, /* difference from 2-pole predictor */
	323	struct g72x_state state_ptr) / coder state pointer */
	324	{
	325	int cnt;
	326	short mag; /* Adaptive predictor, FLOAT A */
	327	short a2p; /* LIMC */
	328	short a1ul; /* UPA1 */
	329	short pks1; /* UPA2 */
	330	short fa1;
	331	char tr; /* tone/transition detector */
	332	short ylint, thr2, dqthr;
	333	short ylfrac, thr1;
	334	short pk0;
	335
	336	pk0 = (dqsez < 0) ? 1 : 0; /* needed in updating predictor poles */
	337
	338	mag = dq & 0x7FFF; /* prediction difference magnitude */
	339	/* TRANS */
	340	ylint = short (state_ptr->yl >> 15); /* exponent part of yl */
	341	ylfrac = (state_ptr->yl >> 10) & 0x1F; /* fractional part of yl */
	342	thr1 = (32 + ylfrac) << ylint; /* threshold */
	343	thr2 = (ylint > 9) ? 31 << 10 : thr1; /* limit thr2 to 31 << 10 */
	344	dqthr = (thr2 + (thr2 >> 1)) >> 1; /* dqthr = 0.75 * thr2 */
	345	if (state_ptr->td == 0) /* signal supposed voice */
	346	tr = 0;
	347	else if (mag <= dqthr) /* supposed data, but small mag */
	348	tr = 0; /* treated as voice */
	349	else /* signal is data (modem) */
	350	tr = 1;
	351
	352	/*
	353	* Quantizer scale factor adaptation.
	354	*/
	355
	356	/* FUNCTW & FILTD & DELAY */
	357	/* update non-steady state step size multiplier */
	358	state_ptr->yu = y + ((wi - y) >> 5);
	359
	360	/* LIMB */
	361	if (state_ptr->yu < 544) /* 544 <= yu <= 5120 */
	362	state_ptr->yu = 544;
	363	else if (state_ptr->yu > 5120)
	364	state_ptr->yu = 5120;
	365
	366	/* FILTE & DELAY */
	367	/* update steady state step size multiplier */
	368	state_ptr->yl += state_ptr->yu + ((-state_ptr->yl) >> 6);
	369
	370	/*
	371	* Adaptive predictor coefficients.
	372	*/
	373	if (tr == 1) { /* reset a's and b's for modem signal */
	374	state_ptr->a[0] = 0;
	375	state_ptr->a[1] = 0;
	376	state_ptr->b[0] = 0;
	377	state_ptr->b[1] = 0;
	378	state_ptr->b[2] = 0;
	379	state_ptr->b[3] = 0;
	380	state_ptr->b[4] = 0;
	381	state_ptr->b[5] = 0;
	382
	383	a2p = 0; /* eliminate Compiler Warnings */
	384	} else { /* update a's and b's */
	385	pks1 = pk0 ^ state_ptr->pk[0]; /* UPA2 */
	386
	387	/* update predictor pole a[1] */
	388	a2p = state_ptr->a[1] - (state_ptr->a[1] >> 7);
	389	if (dqsez != 0) {
	390	fa1 = (pks1) ? state_ptr->a[0] : -state_ptr->a[0];
	391	if (fa1 < -8191) /* a2p = function of fa1 */
	392	a2p -= 0x100;
	393	else if (fa1 > 8191)
	394	a2p += 0xFF;
	395	else
	396	a2p += fa1 >> 5;
	397
	398	if (pk0 ^ state_ptr->pk[1])
	399	/* LIMC */
	400	if (a2p <= -12160)
	401	a2p = -12288;
	402	else if (a2p >= 12416)
	403	a2p = 12288;
	404	else
	405	a2p -= 0x80;
	406	else if (a2p <= -12416)
	407	a2p = -12288;
	408	else if (a2p >= 12160)
	409	a2p = 12288;
	410	else
	411	a2p += 0x80;
	412	}
	413
	414	/* TRIGB & DELAY */
	415	state_ptr->a[1] = a2p;
	416
	417	/* UPA1 */
	418	/* update predictor pole a[0] */
	419	state_ptr->a[0] -= state_ptr->a[0] >> 8;
	420	if (dqsez != 0)
	421	if (pks1 == 0)
	422	state_ptr->a[0] += 192;
	423	else
	424	state_ptr->a[0] -= 192;
	425
	426	/* LIMD */
	427	a1ul = 15360 - a2p;
	428	if (state_ptr->a[0] < -a1ul)
	429	state_ptr->a[0] = -a1ul;
	430	else if (state_ptr->a[0] > a1ul)
	431	state_ptr->a[0] = a1ul;
	432
	433	/* UPB : update predictor zeros b[6] */
	434	for (cnt = 0; cnt < 6; cnt++) {
	435	if (code_size == 5) /* for 40Kbps G.723 */
	436	state_ptr->b[cnt] -= state_ptr->b[cnt] >> 9;
	437	else /* for G.721 and 24Kbps G.723 */
	438	state_ptr->b[cnt] -= state_ptr->b[cnt] >> 8;
	439	if (dq & 0x7FFF) { /* XOR */
	440	if ((dq ^ state_ptr->dq[cnt]) >= 0)
	441	state_ptr->b[cnt] += 128;
	442	else
	443	state_ptr->b[cnt] -= 128;
	444	}
	445	}
	446	}
	447
	448	for (cnt = 5; cnt > 0; cnt--)
	449	state_ptr->dq[cnt] = state_ptr->dq[cnt-1];
	450	/* FLOAT A : convert dq[0] to 4-bit exp, 6-bit mantissa f.p. */
	451	if (mag == 0) {
	452	state_ptr->dq[0] = (dq >= 0) ? 0x20 : 0xFC20;
	453	} else {
	454	state_ptr->dq[0] = (dq >= 0) ?
	455	base2 (mag) : base2 (mag) - 0x400;
	456	}
	457
	458	state_ptr->sr[1] = state_ptr->sr[0];
	459	/* FLOAT B : convert sr to 4-bit exp., 6-bit mantissa f.p. */
	460	if (sr == 0) {
	461	state_ptr->sr[0] = 0x20;
	462	} else if (sr > 0) {
	463	state_ptr->sr[0] = base2(sr);
	464	} else if (sr > -32768) {
	465	mag = -sr;
	466	state_ptr->sr[0] = base2(mag) - 0x400;
	467	} else {
	468	const unsigned short c = 0xFC20;
	469	state_ptr->sr[0] = short(c);
	470	}
	471
	472	/* DELAY A */
	473	state_ptr->pk[1] = state_ptr->pk[0];
	474	state_ptr->pk[0] = pk0;
	475
	476	/* TONE */
	477	if (tr == 1) /* this sample has been treated as data */
	478	state_ptr->td = 0; /* next one will be treated as voice */
	479	else if (a2p < -11776) /* small sample-to-sample correlation */
	480	state_ptr->td = 1; /* signal may be data */
	481	else /* signal is voice */
	482	state_ptr->td = 0;
	483
	484	/*
	485	* Adaptation speed control.
	486	*/
	487	state_ptr->dms += (fi - state_ptr->dms) >> 5; /* FILTA */
	488	state_ptr->dml += (((fi << 2) - state_ptr->dml) >> 7); /* FILTB */
	489
	490	if (tr == 1)
	491	state_ptr->ap = 256;
	492	else if (y < 1536) /* SUBTC */
	493	state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
	494	else if (state_ptr->td == 1)
	495	state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
	496	else if (abs((state_ptr->dms << 2) - state_ptr->dml) >=
	497	(state_ptr->dml >> 3))
	498	state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
	499	else
	500	state_ptr->ap += (-state_ptr->ap) >> 4;
	501	}
	502
	503	/*
	504	* tandem_adjust(sr, se, y, i, sign)
	505	*
	506	* At the end of ADPCM decoding, it simulates an encoder which may be receiving
	507	* the output of this decoder as a tandem process. If the output of the
	508	* simulated encoder differs from the input to this decoder, the decoder output
	509	* is adjusted by one level of A-law or u-law codes.
	510	*
	511	* Input:
	512	* sr decoder output linear PCM sample,
	513	* se predictor estimate sample,
	514	* y quantizer step size,
	515	* i decoder input code,
	516	* sign sign bit of code i
	517	*
	518	* Return:
	519	* adjusted A-law or u-law compressed sample.
	520	*/
	521	int
	522	tandem_adjust_alaw(
	523	int sr, /* decoder output linear PCM sample */
	524	int se, /* predictor estimate sample */
	525	int y, /* quantizer step size */
	526	int i, /* decoder input code */
	527	int sign,
	528	short *qtab)
	529	{
	530	unsigned char sp; /* A-law compressed 8-bit code */
	531	short dx; /* prediction error */
	532	char id; /* quantized prediction error */
	533	int sd; /* adjusted A-law decoded sample value */
	534	int im; /* biased magnitude of i */
	535	int imx; /* biased magnitude of id */
	536
	537	if (sr <= -32768)
	538	sr = -1;
	539	sp = linear2alaw((sr >> 1) << 3); /* short to A-law compression */
	540	dx = (alaw2linear(sp) >> 2) - se; /* 16-bit prediction error */
	541	id = quantize(dx, y, qtab, sign - 1);
	542
	543	if (id == i) { /* no adjustment on sp */
	544	return (sp);
	545	} else { /* sp adjustment needed */
	546	/* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */
	547	im = i ^ sign; /* 2's complement to biased unsigned */
	548	imx = id ^ sign;
	549
	550	if (imx > im) { /* sp adjusted to next lower value */
	551	if (sp & 0x80) {
	552	sd = (sp == 0xD5) ? 0x55 :
	553	((sp ^ 0x55) - 1) ^ 0x55;
	554	} else {
	555	sd = (sp == 0x2A) ? 0x2A :
	556	((sp ^ 0x55) + 1) ^ 0x55;
	557	}
	558	} else { /* sp adjusted to next higher value */
	559	if (sp & 0x80)
	560	sd = (sp == 0xAA) ? 0xAA :
	561	((sp ^ 0x55) + 1) ^ 0x55;
	562	else
	563	sd = (sp == 0x55) ? 0xD5 :
	564	((sp ^ 0x55) - 1) ^ 0x55;
	565	}
	566	return (sd);
	567	}
	568	}
	569
	570	int
	571	tandem_adjust_ulaw(
	572	int sr, /* decoder output linear PCM sample */
	573	int se, /* predictor estimate sample */
	574	int y, /* quantizer step size */
	575	int i, /* decoder input code */
	576	int sign,
	577	short *qtab)
	578	{
	579	unsigned char sp; /* u-law compressed 8-bit code */
	580	short dx; /* prediction error */
	581	char id; /* quantized prediction error */
	582	int sd; /* adjusted u-law decoded sample value */
	583	int im; /* biased magnitude of i */
	584	int imx; /* biased magnitude of id */
	585
	586	if (sr <= -32768)
	587	sr = 0;
	588	sp = linear2ulaw(sr << 2); /* short to u-law compression */
	589	dx = (ulaw2linear(sp) >> 2) - se; /* 16-bit prediction error */
	590	id = quantize(dx, y, qtab, sign - 1);
	591	if (id == i) {
	592	return (sp);
	593	} else {
	594	/* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */
	595	im = i ^ sign; /* 2's complement to biased unsigned */
	596	imx = id ^ sign;
	597	if (imx > im) { /* sp adjusted to next lower value */
	598	if (sp & 0x80)
	599	sd = (sp == 0xFF) ? 0x7E : sp + 1;
	600	else
	601	sd = (sp == 0) ? 0 : sp - 1;
	602
	603	} else { /* sp adjusted to next higher value */
	604	if (sp & 0x80)
	605	sd = (sp == 0x80) ? 0x80 : sp - 1;
	606	else
	607	sd = (sp == 0x7F) ? 0xFE : sp + 1;
	608	}
	609	return (sd);
	610	}
	611	}