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"
Go to the source code of this file.
Data Structures | |
| struct | g726_coder_pvt |
| struct | g726_state |
Defines | |
| #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) |
| 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 | reload (void) |
| 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 = "This paragraph is copyright (c) 2006 by Digium, Inc. \In order for your module to load, it must return this \key via a function called \"key\". Any code which \includes this paragraph must be licensed under the GNU \General Public License version 2 or later (at your \option). In addition to Digium's general reservations \of rights, Digium expressly reserves the right to \allow other parties to license this paragraph under \different terms. Any use of Digium, Inc. trademarks or \logos (including \"Asterisk\" or \"Digium\") without \express written permission of Digium, Inc. is prohibited.\n" , .buildopt_sum = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .reload = reload, } |
| static int | _dqlntab [16] |
| static int | _fitab [16] |
| static int | _witab [16] |
| static 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.
Define Documentation
| #define BUF_SHIFT 5 |
Definition at line 62 of file codec_g726.c.
| #define BUFFER_SAMPLES 8096 /* size for the translation buffers */ |
Definition at line 61 of file codec_g726.c.
| #define WANT_ASM |
Definition at line 45 of file codec_g726.c.
Function Documentation
| static void __reg_module | ( | void | ) | [static] |
Definition at line 878 of file codec_g726.c.
| static void __unreg_module | ( | void | ) | [static] |
Definition at line 878 of file codec_g726.c.
| static int fmult | ( | int | an, |
| int | srn | ||
| ) | [static] |
Definition at line 207 of file codec_g726.c.
References ilog2().
Referenced by predictor_pole(), and predictor_zero().
{
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);
}
| static int g726_decode | ( | int | i, |
| struct g726_state * | state_ptr | ||
| ) | [static] |
Definition at line 590 of file codec_g726.c.
References predictor_pole(), predictor_zero(), reconstruct(), step_size(), and update().
Referenced by g726aal2tolin_framein(), and g726tolin_framein().
{
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
}
| static int g726_encode | ( | int | sl, |
| struct g726_state * | state_ptr | ||
| ) | [static] |
Definition at line 636 of file codec_g726.c.
References predictor_pole(), predictor_zero(), quantize(), reconstruct(), step_size(), and update().
Referenced by lintog726_framein(), and lintog726aal2_framein().
{
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;
}
| static void g726_init_state | ( | struct g726_state * | state_ptr | ) | [static] |
Definition at line 125 of file codec_g726.c.
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().
{
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;
}
| 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 705 of file codec_g726.c.
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.
{
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;
}
| 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 746 of file codec_g726.c.
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.
{
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;
}
| 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 765 of file codec_g726.c.
References ast_trans_pvt::c, 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.
{
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;
}
| static int lintog726_new | ( | struct ast_trans_pvt * | pvt | ) | [static] |
init a new instance of g726_coder_pvt.
Definition at line 695 of file codec_g726.c.
References g726_coder_pvt::g726, g726_init_state(), and ast_trans_pvt::pvt.
{
struct g726_coder_pvt *tmp = pvt->pvt;
g726_init_state(&tmp->g726);
return 0;
}
| 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 724 of file codec_g726.c.
References ast_trans_pvt::c, 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.
{
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;
}
| static int load_module | ( | void | ) | [static] |
Definition at line 844 of file codec_g726.c.
References AST_FORMAT_G726, AST_FORMAT_G726_AAL2, ast_format_set(), AST_FORMAT_SLINEAR, AST_MODULE_LOAD_FAILURE, AST_MODULE_LOAD_SUCCESS, ast_register_translator, ast_translator::dst_format, ast_translator::src_format, and unload_module().
{
int res = 0;
ast_format_set(&g726tolin.src_format, AST_FORMAT_G726, 0);
ast_format_set(&g726tolin.dst_format, AST_FORMAT_SLINEAR, 0);
ast_format_set(&lintog726.src_format, AST_FORMAT_SLINEAR, 0);
ast_format_set(&lintog726.dst_format, AST_FORMAT_G726, 0);
ast_format_set(&g726aal2tolin.src_format, AST_FORMAT_G726_AAL2, 0);
ast_format_set(&g726aal2tolin.dst_format, AST_FORMAT_SLINEAR, 0);
ast_format_set(&lintog726aal2.src_format, AST_FORMAT_SLINEAR, 0);
ast_format_set(&lintog726aal2.dst_format, AST_FORMAT_G726_AAL2, 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_FAILURE;
}
return AST_MODULE_LOAD_SUCCESS;
}
| static int predictor_pole | ( | struct g726_state * | state_ptr | ) | [static] |
Definition at line 235 of file codec_g726.c.
References g726_state::a, fmult(), and g726_state::sr.
Referenced by g726_decode(), and g726_encode().
| static int predictor_zero | ( | struct g726_state * | state_ptr | ) | [static] |
Definition at line 226 of file codec_g726.c.
References g726_state::b, g726_state::dq, and fmult().
Referenced by g726_decode(), and g726_encode().
| static int quan | ( | int | val, |
| int * | table, | ||
| int | size | ||
| ) | [static] |
| static int quantize | ( | int | d, |
| int | y, | ||
| int * | table, | ||
| int | size | ||
| ) | [static] |
Definition at line 278 of file codec_g726.c.
References ilog2(), and quan().
Referenced by g726_encode().
{
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 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;
}
}
| static int reconstruct | ( | int | sign, |
| int | dqln, | ||
| int | y | ||
| ) | [static] |
Definition at line 333 of file codec_g726.c.
Referenced by bridge_p2p_rtp_write(), g726_decode(), and g726_encode().
{
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
}
}
| static int reload | ( | void | ) | [static] |
Definition at line 826 of file codec_g726.c.
References AST_MODULE_LOAD_SUCCESS.
{
return AST_MODULE_LOAD_SUCCESS;
}
| static int step_size | ( | struct g726_state * | state_ptr | ) | [static] |
Definition at line 249 of file codec_g726.c.
References g726_state::ap, g726_state::yl, and g726_state::yu.
Referenced by g726_decode(), g726_encode(), and smb_pitch_shift().
| static int unload_module | ( | void | ) | [static] |
Definition at line 831 of file codec_g726.c.
References ast_unregister_translator().
Referenced by load_module().
{
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;
}
| 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 369 of file codec_g726.c.
References g726_state::a, 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 config_device(), config_line(), connectedline_write(), g726_decode(), g726_encode(), load_pktccops_config(), and redirecting_write().
{
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;
}
}
Variable Documentation
struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "ITU G.726-32kbps G726 Transcoder" , .key = "This paragraph is copyright (c) 2006 by Digium, Inc. \In order for your module to load, it must return this \key via a function called \"key\". Any code which \includes this paragraph must be licensed under the GNU \General Public License version 2 or later (at your \option). In addition to Digium's general reservations \of rights, Digium expressly reserves the right to \allow other parties to license this paragraph under \different terms. Any use of Digium, Inc. trademarks or \logos (including \"Asterisk\" or \"Digium\") without \express written permission of Digium, Inc. is prohibited.\n" , .buildopt_sum = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .reload = reload, } [static] |
Definition at line 878 of file codec_g726.c.
int _dqlntab[16] [static] |
{-2048, 4, 135, 213, 273, 323, 373, 425,
425, 373, 323, 273, 213, 135, 4, -2048}
Definition at line 103 of file codec_g726.c.
int _fitab[16] [static] |
{0, 0, 0, 0x200, 0x200, 0x200, 0x600, 0xE00,
0xE00, 0x600, 0x200, 0x200, 0x200, 0, 0, 0}
Definition at line 114 of file codec_g726.c.
int _witab[16] [static] |
{-12, 18, 41, 64, 112, 198, 355, 1122,
1122, 355, 198, 112, 64, 41, 18, -12}
Definition at line 107 of file codec_g726.c.
struct ast_module_info* ast_module_info = &__mod_info [static] |
Definition at line 878 of file codec_g726.c.
struct ast_translator g726aal2tolin [static] |
Definition at line 806 of file codec_g726.c.
struct ast_translator g726tolin [static] |
Definition at line 786 of file codec_g726.c.
struct ast_translator lintog726 [static] |
Definition at line 796 of file codec_g726.c.
struct ast_translator lintog726aal2 [static] |
Definition at line 816 of file codec_g726.c.
int qtab_721[7] = {-124, 80, 178, 246, 300, 349, 400} [static] |
Definition at line 98 of file codec_g726.c.
