codec_g726.c File Reference

codec_g726.c - translate between signed linear and ITU G.726-32kbps (both RFC3551 and AAL2 codeword packing) More...

#include "asterisk.h"
#include "asterisk/lock.h"
#include "asterisk/linkedlists.h"
#include "asterisk/module.h"
#include "asterisk/config.h"
#include "asterisk/translate.h"
#include "asterisk/utils.h"
#include "log2comp.h"
#include "asterisk/slin.h"
#include "ex_g726.h"

Include dependency graph for codec_g726.c:

Go to the source code of this file.

Data Structures
struct	g726_coder_pvt
struct	g726_state

Macros
#define	BUF_SHIFT   5
#define	BUFFER_SAMPLES   8096 /* size for the translation buffers */
#define	WANT_ASM

Functions
static void	__reg_module (void)
static void	__unreg_module (void)
struct ast_module *	AST_MODULE_SELF_SYM (void)
static int	fmult (int an, int srn)
static int	g726_decode (int i, struct g726_state *state_ptr)
static int	g726_encode (int sl, struct g726_state *state_ptr)
static void	g726_init_state (struct g726_state *state_ptr)
static int	g726aal2tolin_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
	decode packed 4-bit G726 values (AAL2 packing) and store in buffer.
static int	g726tolin_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
	decode packed 4-bit G726 values (RFC3551 packing) and store in buffer.
static int	lintog726_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
	compress and store data (4-bit G726 samples, RFC3551 packing) in outbuf
static int	lintog726_new (struct ast_trans_pvt *pvt)
	init a new instance of g726_coder_pvt.
static int	lintog726aal2_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
	compress and store data (4-bit G726 samples, AAL2 packing) in outbuf
static int	load_module (void)
static int	predictor_pole (struct g726_state *state_ptr)
static int	predictor_zero (struct g726_state *state_ptr)
static int	quan (int val, int *table, int size)
static int	quantize (int d, int y, int *table, int size)
static int	reconstruct (int sign, int dqln, int y)
static int	step_size (struct g726_state *state_ptr)
static int	unload_module (void)
static void	update (int code_size, int y, int wi, int fi, int dq, int sr, int dqsez, struct g726_state *state_ptr)

Variables
static struct ast_module_info	__mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "ITU G.726-32kbps G726 Transcoder" , .key = ASTERISK_GPL_KEY , .buildopt_sum = AST_BUILDOPT_SUM, .support_level = AST_MODULE_SUPPORT_CORE, .load = load_module, .unload = unload_module, }
static int	_dqlntab [16]
static int	_fitab [16]
static int	_witab [16]
static const struct ast_module_info *	ast_module_info = &__mod_info
static struct ast_translator	g726aal2tolin
static struct ast_translator	g726tolin
static struct ast_translator	lintog726
static struct ast_translator	lintog726aal2
static int	qtab_721 [7] = {-124, 80, 178, 246, 300, 349, 400}

Detailed Description

codec_g726.c - translate between signed linear and ITU G.726-32kbps (both RFC3551 and AAL2 codeword packing)

Definition in file codec_g726.c.

Macro Definition Documentation

BUF_SHIFT

#define BUF_SHIFT   5

Definition at line 60 of file codec_g726.c.

BUFFER_SAMPLES

#define BUFFER_SAMPLES   8096 /* size for the translation buffers */

Definition at line 59 of file codec_g726.c.

WANT_ASM

#define WANT_ASM

Definition at line 43 of file codec_g726.c.

Function Documentation

__reg_module()

static void __reg_module ( void  )

static

Definition at line 903 of file codec_g726.c.

__unreg_module()

static void __unreg_module ( void  )

static

Definition at line 903 of file codec_g726.c.

AST_MODULE_SELF_SYM()

struct ast_module * AST_MODULE_SELF_SYM

(

void

)

Definition at line 903 of file codec_g726.c.

fmult()

static int fmult ( int  an, int  srn  )

static

Definition at line 205 of file codec_g726.c.

{
    int     anmag, anexp, anmant;
    int     wanexp, wanmant;
    int     retval;
 
    anmag = (an > 0) ? an : ((-an) & 0x1FFF);
    anexp = ilog2(anmag) - 5;
    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);
}

References ilog2().

Referenced by predictor_pole(), and predictor_zero().

g726_decode()

static int g726_decode ( int  i, struct g726_state *  state_ptr  )

static

Definition at line 588 of file codec_g726.c.

{
    int     sezi, sez, se;  /* ACCUM */
    int     y;          /* MIX */
    int     sr;         /* ADDB */
    int     dq;
    int     dqsez;
 
    i &= 0x0f;          /* mask to get proper bits */
#ifdef NOT_BLI
    sezi = predictor_zero(state_ptr);
    sez = sezi;
    se = sezi + predictor_pole(state_ptr);  /* estimated signal */
#else
    sezi = predictor_zero(state_ptr);
    sez = sezi >> 1;
    se = (sezi + predictor_pole(state_ptr)) >> 1;   /* estimated signal */
#endif
 
    y = step_size(state_ptr);   /* dynamic quantizer step size */
 
    dq = reconstruct(i & 8, _dqlntab[i], y); /* quantized diff. */
 
#ifdef NOT_BLI
    sr = se + dq;               /* reconst. signal */
    dqsez = dq + sez;           /* pole prediction diff. */
#else
    sr = (dq < 0) ? se - (dq & 0x3FFF) : se + dq;   /* reconst. signal */
    dqsez = sr - se + sez;      /* pole prediction diff. */
#endif
 
    update(4, y, _witab[i] << 5, _fitab[i], dq, sr, dqsez, state_ptr);
 
#ifdef NOT_BLI
    return (sr >> 10);  /* sr was 26-bit dynamic range */
#else
    return (sr << 2);   /* sr was 14-bit dynamic range */
#endif
}

References _dqlntab, _fitab, _witab, predictor_pole(), predictor_zero(), reconstruct(), step_size(), and update().

Referenced by g726aal2tolin_framein(), and g726tolin_framein().

g726_encode()

static int g726_encode ( int  sl, struct g726_state *  state_ptr  )

static

Definition at line 634 of file codec_g726.c.

{
    int     sezi, se, sez;      /* ACCUM */
    int     d;          /* SUBTA */
    int     sr;         /* ADDB */
    int     y;          /* MIX */
    int     dqsez;          /* ADDC */
    int     dq, i;
 
#ifdef NOT_BLI
    sl <<= 10;          /* 26-bit dynamic range */
 
    sezi = predictor_zero(state_ptr);
    sez = sezi;
    se = sezi + predictor_pole(state_ptr);  /* estimated signal */
#else
    sl >>= 2;           /* 14-bit dynamic range */
 
    sezi = predictor_zero(state_ptr);
    sez = sezi >> 1;
    se = (sezi + predictor_pole(state_ptr)) >> 1;   /* estimated signal */
#endif
 
    d = sl - se;                /* estimation difference */
 
    /* quantize the prediction difference */
    y = step_size(state_ptr);       /* quantizer step size */
#ifdef NOT_BLI
    d /= 0x1000;
#endif
    i = quantize(d, y, qtab_721, 7);    /* i = G726 code */
 
    dq = reconstruct(i & 8, _dqlntab[i], y);    /* quantized est diff */
 
#ifdef NOT_BLI
    sr = se + dq;               /* reconst. signal */
    dqsez = dq + sez;           /* pole prediction diff. */
#else
    sr = (dq < 0) ? se - (dq & 0x3FFF) : se + dq;   /* reconst. signal */
    dqsez = sr - se + sez;          /* pole prediction diff. */
#endif
 
    update(4, y, _witab[i] << 5, _fitab[i], dq, sr, dqsez, state_ptr);
 
    return i;
}

References _dqlntab, _fitab, _witab, d, predictor_pole(), predictor_zero(), qtab_721, quantize(), reconstruct(), step_size(), and update().

Referenced by lintog726_framein(), and lintog726aal2_framein().

g726_init_state()

static void g726_init_state ( struct g726_state *  state_ptr )

static

Definition at line 123 of file codec_g726.c.

{
    int     cnta;
 
    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;
#ifdef NOT_BLI
        state_ptr->sr[cnta] = 1;
#else
        state_ptr->sr[cnta] = 32;
#endif
    }
    for (cnta = 0; cnta < 6; cnta++) {
        state_ptr->b[cnta] = 0;
#ifdef NOT_BLI
        state_ptr->dq[cnta] = 1;
#else
        state_ptr->dq[cnta] = 32;
#endif
    }
    state_ptr->td = 0;
}

References g726_state::a, g726_state::ap, g726_state::b, g726_state::dml, g726_state::dms, g726_state::dq, g726_state::pk, g726_state::sr, g726_state::td, g726_state::yl, and g726_state::yu.

Referenced by lintog726_new().

g726aal2tolin_framein()

static int g726aal2tolin_framein ( struct ast_trans_pvt *  pvt, struct ast_frame *  f  )

static

decode packed 4-bit G726 values (AAL2 packing) and store in buffer.

Definition at line 703 of file codec_g726.c.

{
    struct g726_coder_pvt *tmp = pvt->pvt;
    unsigned char *src = f->data.ptr;
    int16_t *dst = pvt->outbuf.i16 + pvt->samples;
    unsigned int i;
 
    for (i = 0; i < f->datalen; i++) {
        *dst++ = g726_decode((src[i] >> 4) & 0xf, &tmp->g726);
        *dst++ = g726_decode(src[i] & 0x0f, &tmp->g726);
    }
 
    pvt->samples += f->samples;
    pvt->datalen += 2 * f->samples; /* 2 bytes/sample */
 
    return 0;
}

References ast_frame::data, ast_frame::datalen, ast_trans_pvt::datalen, g726_coder_pvt::g726, g726_decode(), ast_trans_pvt::i16, ast_trans_pvt::outbuf, ast_frame::ptr, ast_trans_pvt::pvt, ast_frame::samples, and ast_trans_pvt::samples.

g726tolin_framein()

static int g726tolin_framein ( struct ast_trans_pvt *  pvt, struct ast_frame *  f  )

static

decode packed 4-bit G726 values (RFC3551 packing) and store in buffer.

Definition at line 744 of file codec_g726.c.

{
    struct g726_coder_pvt *tmp = pvt->pvt;
    unsigned char *src = f->data.ptr;
    int16_t *dst = pvt->outbuf.i16 + pvt->samples;
    unsigned int i;
 
    for (i = 0; i < f->datalen; i++) {
        *dst++ = g726_decode(src[i] & 0x0f, &tmp->g726);
        *dst++ = g726_decode((src[i] >> 4) & 0xf, &tmp->g726);
    }
 
    pvt->samples += f->samples;
    pvt->datalen += 2 * f->samples; /* 2 bytes/sample */
 
    return 0;
}

References ast_frame::data, ast_frame::datalen, ast_trans_pvt::datalen, g726_coder_pvt::g726, g726_decode(), ast_trans_pvt::i16, ast_trans_pvt::outbuf, ast_frame::ptr, ast_trans_pvt::pvt, ast_frame::samples, and ast_trans_pvt::samples.

lintog726_framein()

static int lintog726_framein ( struct ast_trans_pvt *  pvt, struct ast_frame *  f  )

static

compress and store data (4-bit G726 samples, RFC3551 packing) in outbuf

Definition at line 763 of file codec_g726.c.

{
    struct g726_coder_pvt *tmp = pvt->pvt;
    int16_t *src = f->data.ptr;
    unsigned int i;
 
    for (i = 0; i < f->samples; i++) {
        unsigned char d = g726_encode(src[i], &tmp->g726); /* this sample */
 
        if (tmp->next_flag & 0x80) {    /* merge with leftover sample */
            pvt->outbuf.c[pvt->datalen++] = (d << 4) | (tmp->next_flag & 0xf);
            pvt->samples += 2;  /* 2 samples per byte */
            tmp->next_flag = 0;
        } else {
            tmp->next_flag = 0x80 | d;
        }
    }
 
    return 0;
}

References ast_trans_pvt::c, d, ast_frame::data, ast_trans_pvt::datalen, g726_coder_pvt::g726, g726_encode(), g726_coder_pvt::next_flag, ast_trans_pvt::outbuf, ast_frame::ptr, ast_trans_pvt::pvt, ast_frame::samples, and ast_trans_pvt::samples.

lintog726_new()

static int lintog726_new ( struct ast_trans_pvt *  pvt )

static

init a new instance of g726_coder_pvt.

Definition at line 693 of file codec_g726.c.

{
    struct g726_coder_pvt *tmp = pvt->pvt;
 
    g726_init_state(&tmp->g726);
 
    return 0;
}

References g726_coder_pvt::g726, g726_init_state(), and ast_trans_pvt::pvt.

lintog726aal2_framein()

static int lintog726aal2_framein ( struct ast_trans_pvt *  pvt, struct ast_frame *  f  )

static

compress and store data (4-bit G726 samples, AAL2 packing) in outbuf

Definition at line 722 of file codec_g726.c.

{
    struct g726_coder_pvt *tmp = pvt->pvt;
    int16_t *src = f->data.ptr;
    unsigned int i;
 
    for (i = 0; i < f->samples; i++) {
        unsigned char d = g726_encode(src[i], &tmp->g726); /* this sample */
 
        if (tmp->next_flag & 0x80) {    /* merge with leftover sample */
            pvt->outbuf.c[pvt->datalen++] = ((tmp->next_flag & 0xf)<< 4) | d;
            pvt->samples += 2;  /* 2 samples per byte */
            tmp->next_flag = 0;
        } else {
            tmp->next_flag = 0x80 | d;
        }
    }
 
    return 0;
}

References ast_trans_pvt::c, d, ast_frame::data, ast_trans_pvt::datalen, g726_coder_pvt::g726, g726_encode(), g726_coder_pvt::next_flag, ast_trans_pvt::outbuf, ast_frame::ptr, ast_trans_pvt::pvt, ast_frame::samples, and ast_trans_pvt::samples.

load_module()

static int load_module ( void  )

static

Definition at line 881 of file codec_g726.c.

{
    int res = 0;
 
    res |= ast_register_translator(&g726tolin);
    res |= ast_register_translator(&lintog726);
 
    res |= ast_register_translator(&g726aal2tolin);
    res |= ast_register_translator(&lintog726aal2);
 
    if (res) {
        unload_module();
        return AST_MODULE_LOAD_DECLINE;
    }
 
    return AST_MODULE_LOAD_SUCCESS;
}

References AST_MODULE_LOAD_DECLINE, AST_MODULE_LOAD_SUCCESS, ast_register_translator, g726aal2tolin, g726tolin, lintog726, lintog726aal2, and unload_module().

predictor_pole()

static int predictor_pole ( struct g726_state *  state_ptr )

static

Definition at line 233 of file codec_g726.c.

{
    return (fmult(state_ptr->a[1] >> 2, state_ptr->sr[1]) +
            fmult(state_ptr->a[0] >> 2, state_ptr->sr[0]));
}

References g726_state::a, fmult(), and g726_state::sr.

Referenced by g726_decode(), and g726_encode().

predictor_zero()

static int predictor_zero ( struct g726_state *  state_ptr )

static

Definition at line 224 of file codec_g726.c.

{
    int     i;
    int     sezi;
    for (sezi = 0, i = 0; i < 6; i++)           /* ACCUM */
        sezi += fmult(state_ptr->b[i] >> 2, state_ptr->dq[i]);
    return sezi;
}

References g726_state::b, g726_state::dq, and fmult().

Referenced by g726_decode(), and g726_encode().

quan()

static int quan ( int  val, int *  table, int  size  )

static

Definition at line 160 of file codec_g726.c.

{
    int     i;
 
    for (i = 0; i < size && val >= *table; ++i, ++table)
        ;
    return i;
}

Referenced by quantize().

quantize()

static int quantize ( int  d, int  y, int *  table, int  size  )

static

Definition at line 276 of file codec_g726.c.

{
    int     dqm;    /* Magnitude of 'd' */
    int     exp;    /* Integer part of base 2 log of 'd' */
    int     mant;   /* Fractional part of base 2 log */
    int     dl;     /* Log of magnitude of 'd' */
    int     dln;    /* Step size scale factor normalized log */
    int     i;
 
    /*
     * LOG
     *
     * Compute base 2 log of 'd', and store in 'dl'.
     */
    dqm = abs(d);
    exp = ilog2(dqm);
    if (exp < 0) {
        exp = 0;
    }
    mant = ((dqm << 7) >> exp) & 0x7F;  /* Fractional portion. */
    dl = (exp << 7) | mant;
 
    /*
     * SUBTB
     *
     * "Divide" by step size multiplier.
     */
    dln = dl - (y >> 2);
 
    /*
     * QUAN
     *
     * Obtain codeword 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;
    }
}

References abs, d, ilog2(), and quan().

Referenced by g726_encode().

reconstruct()

static int reconstruct ( int  sign, int  dqln, int  y  )

static

Definition at line 331 of file codec_g726.c.

{
    int     dql;    /* Log of 'dq' magnitude */
    int     dex;    /* Integer part of log */
    int     dqt;
    int     dq; /* Reconstructed difference signal sample */
 
    dql = dqln + (y >> 2);  /* ADDA */
 
    if (dql < 0) {
#ifdef NOT_BLI
        return (sign) ? -1 : 1;
#else
        return (sign) ? -0x8000 : 0;
#endif
    } else {        /* ANTILOG */
        dex = (dql >> 7) & 15;
        dqt = 128 + (dql & 127);
#ifdef NOT_BLI
        dq = ((dqt << 19) >> (14 - dex));
        return (sign) ? -dq : dq;
#else
        dq = (dqt << 7) >> (14 - dex);
        return (sign) ? (dq - 0x8000) : dq;
#endif
    }
}

Referenced by bridge_p2p_rtp_write(), g726_decode(), and g726_encode().

step_size()

static int step_size ( struct g726_state *  state_ptr )

static

Definition at line 247 of file codec_g726.c.

{
    int y, dif, al;
 
    if (state_ptr->ap >= 256) {
        return state_ptr->yu;
    }
 
    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;
}

References g726_state::ap, g726_state::yl, and g726_state::yu.

Referenced by g726_decode(), g726_encode(), and smb_pitch_shift().

unload_module()

static int unload_module ( void  )

static

Definition at line 868 of file codec_g726.c.

{
    int res = 0;
 
    res |= ast_unregister_translator(&g726tolin);
    res |= ast_unregister_translator(&lintog726);
 
    res |= ast_unregister_translator(&g726aal2tolin);
    res |= ast_unregister_translator(&lintog726aal2);
 
    return res;
}

References ast_unregister_translator(), g726aal2tolin, g726tolin, lintog726, and lintog726aal2.

Referenced by load_module().

update()

static void update ( int  code_size, int  y, int  wi, int  fi, int  dq, int  sr, int  dqsez, struct g726_state *  state_ptr  )

static

Definition at line 367 of file codec_g726.c.

{
    int     cnt;
    int     mag;        /* Adaptive predictor, FLOAT A */
#ifndef NOT_BLI
    int     exp;
#endif
    int     a2p=0;      /* LIMC */
    int     a1ul;       /* UPA1 */
    int     pks1;       /* UPA2 */
    int     fa1;
    int     tr;         /* tone/transition detector */
    int     ylint, thr2, dqthr;
    int     ylfrac, thr1;
    int     pk0;
 
    pk0 = (dqsez < 0) ? 1 : 0;  /* needed in updating predictor poles */
 
#ifdef NOT_BLI
    mag = abs(dq / 0x1000); /* prediction difference magnitude */
#else
    mag = dq & 0x7FFF;      /* prediction difference magnitude */
#endif
    /* TRANS */
    ylint = 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;
    } 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 (mag) {  /* 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];
#ifdef NOT_BLI
    state_ptr->dq[0] = dq;
#else
    /* FLOAT A : convert dq[0] to 4-bit exp, 6-bit mantissa f.p. */
    if (mag == 0) {
        state_ptr->dq[0] = (dq >= 0) ? 0x20 : 0x20 - 0x400;
    } else {
        exp = ilog2(mag) + 1;
        state_ptr->dq[0] = (dq >= 0) ?
            (exp << 6) + ((mag << 6) >> exp) :
            (exp << 6) + ((mag << 6) >> exp) - 0x400;
    }
#endif
 
    state_ptr->sr[1] = state_ptr->sr[0];
#ifdef NOT_BLI
    state_ptr->sr[0] = sr;
#else
    /* 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) {
        exp = ilog2(sr) + 1;
        state_ptr->sr[0] = (exp << 6) + ((sr << 6) >> exp);
    } else if (sr > -0x8000) {
        mag = -sr;
        exp = ilog2(mag) + 1;
        state_ptr->sr[0] =  (exp << 6) + ((mag << 6) >> exp) - 0x400;
    } else
        state_ptr->sr[0] = 0x20 - 0x400;
#endif
 
    /* 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;
    }
}

References g726_state::a, abs, g726_state::ap, g726_state::b, g726_state::dml, g726_state::dms, g726_state::dq, ilog2(), g726_state::pk, g726_state::sr, g726_state::td, g726_state::yl, and g726_state::yu.

Referenced by ast_bridge_publish_state(), ast_channel_publish_final_snapshot(), ast_channel_publish_snapshot(), ast_channel_queue_connected_line_update(), ast_channel_queue_redirecting_update(), ast_channel_set_caller(), ast_channel_set_caller_event(), ast_channel_set_connected_line(), ast_channel_set_redirecting(), ast_channel_update_connected_line(), ast_channel_update_redirecting(), ast_connected_line_build_data(), ast_party_caller_set(), ast_party_connected_line_set(), ast_party_id_set(), ast_party_redirecting_set(), ast_redirecting_build_data(), AST_TEST_DEFINE(), AST_TEST_DEFINE(), bridge_publish_state_from_blob(), bridge_snapshot_update(), bridge_snapshot_update_create(), bridge_snapshot_update_dtor(), bridge_topics_destroy(), cache_update(), cache_update_cb(), caching_topic_exec(), cel_snapshot_update_cb(), channel_snapshot_update(), channel_snapshot_update_create(), channel_snapshot_update_dtor(), connectedline_write(), copy_redirecting_id(), find_route(), g726_decode(), g726_encode(), handle_bridge_enter_message(), handle_bridge_leave_message(), handle_channel_snapshot_update_message(), load_module(), party_id_build_data(), redirecting_write(), send_colp_to_agent(), set_redirecting(), set_redirecting_id(), stasis_cache_update_dtor(), sub_bridge_update_handler(), sub_channel_update_handler(), sub_endpoint_update_handler(), unload_module(), update_create(), and updates().

Variable Documentation

__mod_info

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "ITU G.726-32kbps G726 Transcoder" , .key = ASTERISK_GPL_KEY , .buildopt_sum = AST_BUILDOPT_SUM, .support_level = AST_MODULE_SUPPORT_CORE, .load = load_module, .unload = unload_module, }

static

Definition at line 903 of file codec_g726.c.

_dqlntab

int _dqlntab[16]

static

Initial value:

= {-2048, 4, 135, 213, 273, 323, 373, 425,
                425, 373, 323, 273, 213, 135, 4, -2048}

Definition at line 101 of file codec_g726.c.

                          {-2048, 4, 135, 213, 273, 323, 373, 425,
                425, 373, 323, 273, 213, 135, 4, -2048};

Referenced by g726_decode(), and g726_encode().

_fitab

int _fitab[16]

static

Initial value:

= {0, 0, 0, 0x200, 0x200, 0x200, 0x600, 0xE00,
                0xE00, 0x600, 0x200, 0x200, 0x200, 0, 0, 0}

Definition at line 112 of file codec_g726.c.

                        {0, 0, 0, 0x200, 0x200, 0x200, 0x600, 0xE00,
                0xE00, 0x600, 0x200, 0x200, 0x200, 0, 0, 0};

Referenced by g726_decode(), and g726_encode().

_witab

int _witab[16]

static

Initial value:

= {-12, 18, 41, 64, 112, 198, 355, 1122,
                1122, 355, 198, 112, 64, 41, 18, -12}

Definition at line 105 of file codec_g726.c.

                        {-12, 18, 41, 64, 112, 198, 355, 1122,
                1122, 355, 198, 112, 64, 41, 18, -12};

Referenced by g726_decode(), and g726_encode().

ast_module_info

const struct ast_module_info* ast_module_info = &__mod_info

static

Definition at line 903 of file codec_g726.c.

g726aal2tolin

struct ast_translator g726aal2tolin

static

Definition at line 826 of file codec_g726.c.

                                             {
    .name = "g726aal2tolin",
    .src_codec = {
        .name = "g726aal2",
        .type = AST_MEDIA_TYPE_AUDIO,
        .sample_rate = 8000,
    },
    .dst_codec = {
        .name = "slin",
        .type = AST_MEDIA_TYPE_AUDIO,
        .sample_rate = 8000,
    },
    .format = "slin",
    .newpvt = lintog726_new,    /* same for both directions */
    .framein = g726aal2tolin_framein,
    .sample = g726_sample,
    .desc_size = sizeof(struct g726_coder_pvt),
    .buffer_samples = BUFFER_SAMPLES,
    .buf_size = BUFFER_SAMPLES * 2,
};

Referenced by load_module(), and unload_module().

g726tolin

struct ast_translator g726tolin

static

Definition at line 784 of file codec_g726.c.

                                         {
    .name = "g726tolin",
    .src_codec = {
        .name = "g726",
        .type = AST_MEDIA_TYPE_AUDIO,
        .sample_rate = 8000,
    },
    .dst_codec = {
        .name = "slin",
        .type = AST_MEDIA_TYPE_AUDIO,
        .sample_rate = 8000,
    },
    .format = "slin",
    .newpvt = lintog726_new,    /* same for both directions */
    .framein = g726tolin_framein,
    .sample = g726_sample,
    .desc_size = sizeof(struct g726_coder_pvt),
    .buffer_samples = BUFFER_SAMPLES,
    .buf_size = BUFFER_SAMPLES * 2,
};

Referenced by load_module(), and unload_module().

lintog726

struct ast_translator lintog726

static

Definition at line 805 of file codec_g726.c.

                                         {
    .name = "lintog726",
    .src_codec = {
        .name = "slin",
        .type = AST_MEDIA_TYPE_AUDIO,
        .sample_rate = 8000,
    },
    .dst_codec = {
        .name = "g726",
        .type = AST_MEDIA_TYPE_AUDIO,
        .sample_rate = 8000,
    },
    .format = "g726",
    .newpvt = lintog726_new,    /* same for both directions */
    .framein = lintog726_framein,
    .sample = slin8_sample,
    .desc_size = sizeof(struct g726_coder_pvt),
    .buffer_samples = BUFFER_SAMPLES,
    .buf_size = BUFFER_SAMPLES/2,
};

Referenced by load_module(), and unload_module().

lintog726aal2

struct ast_translator lintog726aal2

static

Definition at line 847 of file codec_g726.c.

                                             {
    .name = "lintog726aal2",
    .src_codec = {
        .name = "slin",
        .type = AST_MEDIA_TYPE_AUDIO,
        .sample_rate = 8000,
    },
    .dst_codec = {
        .name = "g726aal2",
        .type = AST_MEDIA_TYPE_AUDIO,
        .sample_rate = 8000,
    },
    .format = "g726aal2",
    .newpvt = lintog726_new,    /* same for both directions */
    .framein = lintog726aal2_framein,
    .sample = slin8_sample,
    .desc_size = sizeof(struct g726_coder_pvt),
    .buffer_samples = BUFFER_SAMPLES,
    .buf_size = BUFFER_SAMPLES / 2,
};

Referenced by load_module(), and unload_module().

qtab_721

int qtab_721[7] = {-124, 80, 178, 246, 300, 349, 400}

static

Definition at line 96 of file codec_g726.c.

{-124, 80, 178, 246, 300, 349, 400};

Referenced by g726_encode().