/*
* Asterisk -- An open source telephony toolkit.
*
* Based on frompcm.c and topcm.c from the Emiliano MIPL browser/
* interpreter. See http://www.bsdtelephony.com.mx
*
* Copyright (c) 2001 - 2005 Digium, Inc.
* All rights reserved.
*
* Karl Sackett <krs@linux-support.net>, 2001-03-21
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
/*! \file
*
* \brief codec_adpcm.c - translate between signed linear and Dialogic ADPCM
*
* \ingroup codecs
*/
#include <fcntl.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "asterisk.h"
ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#include "asterisk/lock.h"
#include "asterisk/logger.h"
#include "asterisk/module.h"
#include "asterisk/config.h"
#include "asterisk/options.h"
#include "asterisk/translate.h"
#include "asterisk/channel.h"
#include "asterisk/utils.h"
/* define NOT_BLI to use a faster but not bit-level identical version */
/* #define NOT_BLI */
#define BUFFER_SIZE 8096 /* size for the translation buffers */
AST_MUTEX_DEFINE_STATIC(localuser_lock);
static int localusecnt = 0;
static char *tdesc = "Adaptive Differential PCM Coder/Decoder";
static int useplc = 0;
/* Sample frame data */
#include "slin_adpcm_ex.h"
#include "adpcm_slin_ex.h"
/*
* Step size index shift table
*/
static int indsft[8] = { -1, -1, -1, -1, 2, 4, 6, 8 };
/*
* Step size table, where stpsz[i]=floor[16*(11/10)^i]
*/
static int stpsz[49] = {
16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55, 60, 66, 73,
80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230, 253, 279,
307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963,
1060, 1166, 1282, 1411, 1552
};
/*
* Decoder/Encoder state
* States for both encoder and decoder are synchronized
*/
struct adpcm_state {
int ssindex;
int signal;
int zero_count;
int next_flag;
};
/*
* Decode(encoded)
* Decodes the encoded nibble from the adpcm file.
*
* Results:
* Returns the encoded difference.
*
* Side effects:
* Sets the index to the step size table for the next encode.
*/
static inline short decode(int encoded, struct adpcm_state *state)
{
int diff;
int step;
int sign;
step = stpsz[state->ssindex];
sign = encoded & 0x08;
encoded &= 0x07;
#ifdef NOT_BLI
diff = (((encoded << 1) + 1) * step) >> 3;
#else /* BLI code */
diff = step >> 3;
if (encoded & 4)
diff += step;
if (encoded & 2)
diff += step >> 1;
if (encoded & 1)
diff += step >> 2;
if ((encoded >> 1) & step & 0x1)
diff++;
#endif
if (sign)
diff = -diff;
if (state->next_flag & 0x1)
state->signal -= 8;
else if (state->next_flag & 0x2)
state->signal += 8;
state->signal += diff;
if (state->signal > 2047)
state->signal = 2047;
else if (state->signal < -2047)
state->signal = -2047;
state->next_flag = 0;
#ifdef AUTO_RETURN
if (encoded)
state->zero_count = 0;
else if (++(state->zero_count) == 24) {
state->zero_count = 0;
if (state->signal > 0)
state->next_flag = 0x1;
else if (state->signal < 0)
state->next_flag = 0x2;
}
#endif
state->ssindex += indsft[encoded];
if (state->ssindex < 0)
state->ssindex = 0;
else if (state->ssindex > 48)
state->ssindex = 48;
return state->signal << 4;
}
/*
* Adpcm
* Takes a signed linear signal and encodes it as ADPCM
* For more information see http://support.dialogic.com/appnotes/adpcm.pdf
*
* Results:
* Foo.
*
* Side effects:
* signal gets updated with each pass.
*/
static inline int adpcm(short csig, struct adpcm_state *state)
{
int diff;
int step;
int encoded;
/*
* Clip csig if too large or too small
*/
csig >>= 4;
step = stpsz[state->ssindex];
diff = csig - state->signal;
#ifdef NOT_BLI
if (diff < 0) {
encoded = (-diff << 2) / step;
if (encoded > 7)
encoded = 7;
encoded |= 0x08;
} else {
encoded = (diff << 2) / step;
if (encoded > 7)
encoded = 7;
}
#else /* BLI code */
if (diff < 0) {
encoded = 8;
diff = -diff;
} else
encoded = 0;
if (diff >= step) {
encoded |= 4;
diff -= step;
}
step >>= 1;
if (diff >= step) {
encoded |= 2;
diff -= step;
}
step >>= 1;
if (diff >= step)
encoded |= 1;
#endif /* NOT_BLI */
/* feedback to state */
decode(encoded, state);
return encoded;
}
/*
* Private workspace for translating signed linear signals to ADPCM.
*/
struct adpcm_encoder_pvt
{
struct ast_frame f;
char offset[AST_FRIENDLY_OFFSET]; /* Space to build offset */
short inbuf[BUFFER_SIZE]; /* Unencoded signed linear values */
unsigned char outbuf[BUFFER_SIZE]; /* Encoded ADPCM, two nibbles to a word */
struct adpcm_state state;
int tail;
};
/*
* Private workspace for translating ADPCM signals to signed linear.
*/
struct adpcm_decoder_pvt
{
struct ast_frame f;
char offset[AST_FRIENDLY_OFFSET]; /* Space to build offset */
short outbuf[BUFFER_SIZE]; /* Decoded signed linear values */
struct adpcm_state state;
int tail;
plc_state_t plc;
};
/*
* AdpcmToLin_New
* Create a new instance of adpcm_decoder_pvt.
*
* Results:
* Returns a pointer to the new instance.
*
* Side effects:
* None.
*/
static struct ast_translator_pvt *adpcmtolin_new(void)
{
struct adpcm_decoder_pvt *tmp;
if ((tmp = ast_calloc(1, sizeof(*tmp)))) {
tmp->tail = 0;
plc_init(&tmp->plc);
localusecnt++;
ast_update_use_count();
}
return (struct ast_translator_pvt *)tmp;
}
/*
* LinToAdpcm_New
* Create a new instance of adpcm_encoder_pvt.
*
* Results:
* Returns a pointer to the new instance.
*
* Side effects:
* None.
*/
static struct ast_translator_pvt *lintoadpcm_new(void)
{
struct adpcm_encoder_pvt *tmp;
if ((tmp = ast_calloc(1, sizeof(*tmp)))) {
localusecnt++;
ast_update_use_count();
tmp->tail = 0;
}
return (struct ast_translator_pvt *)tmp;
}
/*
* AdpcmToLin_FrameIn
* Take an input buffer with packed 4-bit ADPCM values and put decoded PCM in outbuf,
* if there is room left.
*
* Results:
* Foo
*
* Side effects:
* tmp->tail is the number of packed values in the buffer.
*/
static int adpcmtolin_framein(struct ast_translator_pvt *pvt, struct ast_frame *f)
{
struct adpcm_decoder_pvt *tmp = (struct adpcm_decoder_pvt *)pvt;
int x;
unsigned char *b;
if(f->datalen == 0) { /* perform PLC with nominal framesize of 20ms/160 samples */
if((tmp->tail + 160) > sizeof(tmp->outbuf) / 2) {
ast_log(LOG_WARNING, "Out of buffer space\n");
return -1;
}
if(useplc) {
plc_fillin(&tmp->plc, tmp->outbuf+tmp->tail, 160);
tmp->tail += 160;
}
return 0;
}
if (f->datalen * 4 + tmp->tail * 2 > sizeof(tmp->outbuf)) {
ast_log(LOG_WARNING, "Out of buffer space\n");
return -1;
}
b = f->data;
for (x=0;x<f->datalen;x++) {
tmp->outbuf[tmp->tail++] = decode((b[x] >> 4) & 0xf, &tmp->state);
tmp->outbuf[tmp->tail++] = decode(b[x] & 0x0f, &tmp->state);
}
if(useplc)
plc_rx(&tmp->plc, tmp->outbuf+tmp->tail-f->datalen*2, f->datalen*2);
return 0;
}
/*
* AdpcmToLin_FrameOut
* Convert 4-bit ADPCM encoded signals to 16-bit signed linear.
*
* Results:
* Converted signals are placed in tmp->f.data, tmp->f.datalen
* and tmp->f.samples are calculated.
*
* Side effects:
* None.
*/
static struct ast_frame *adpcmtolin_frameout(struct ast_translator_pvt *pvt)
{
struct adpcm_decoder_pvt *tmp = (struct adpcm_decoder_pvt *)pvt;
if (!tmp->tail)
return NULL;
tmp->f.frametype = AST_FRAME_VOICE;
tmp->f.subclass = AST_FORMAT_SLINEAR;
tmp->f.datalen = tmp->tail * 2;
tmp->f.samples = tmp->tail;
tmp->f.mallocd = 0;
tmp->f.offset = AST_FRIENDLY_OFFSET;
tmp->f.src = __PRETTY_FUNCTION__;
tmp->f.data = tmp->outbuf;
tmp->tail = 0;
return &tmp->f;
}
/*
* LinToAdpcm_FrameIn
* Fill an input buffer with 16-bit signed linear PCM values.
*
* Results:
* None.
*
* Side effects:
* tmp->tail is number of signal values in the input buffer.
*/
static int lintoadpcm_framein(struct ast_translator_pvt *pvt, struct ast_frame *f)
{
struct adpcm_encoder_pvt *tmp = (struct adpcm_encoder_pvt *)pvt;
if ((tmp->tail + f->datalen / 2) < (sizeof(tmp->inbuf) / 2)) {
memcpy(&tmp->inbuf[tmp->tail], f->data, f->datalen);
tmp->tail += f->datalen / 2;
} else {
ast_log(LOG_WARNING, "Out of buffer space\n");
return -1;
}
return 0;
}
/*
* LinToAdpcm_FrameOut
* Convert a buffer of raw 16-bit signed linear PCM to a buffer
* of 4-bit ADPCM packed two to a byte (Big Endian).
*
* Results:
* Foo
*
* Side effects:
* Leftover inbuf data gets packed, tail gets updated.
*/
static struct ast_frame *lintoadpcm_frameout(struct ast_translator_pvt *pvt)
{
struct adpcm_encoder_pvt *tmp = (struct adpcm_encoder_pvt *)pvt;
int i_max, i;
if (tmp->tail < 2)
return NULL;
i_max = tmp->tail & ~1; /* atomic size is 2 samples */
/* What is this, state debugging? should be #ifdef'd then
tmp->outbuf[0] = tmp->ssindex & 0xff;
tmp->outbuf[1] = (tmp->signal >> 8) & 0xff;
tmp->outbuf[2] = (tmp->signal & 0xff);
tmp->outbuf[3] = tmp->zero_count;
tmp->outbuf[4] = tmp->next_flag;
*/
for (i = 0; i < i_max; i+=2) {
tmp->outbuf[i/2] =
(adpcm(tmp->inbuf[i ], &tmp->state) << 4) |
(adpcm(tmp->inbuf[i+1], &tmp->state) );
};
tmp->f.frametype = AST_FRAME_VOICE;
tmp->f.subclass = AST_FORMAT_ADPCM;
tmp->f.samples = i_max;
tmp->f.mallocd = 0;
tmp->f.offset = AST_FRIENDLY_OFFSET;
tmp->f.src = __PRETTY_FUNCTION__;
tmp->f.data = tmp->outbuf;
tmp->f.datalen = i_max / 2;
/*
* If there is a signal left over (there should be no more than
* one) move it to the beginning of the input buffer.
*/
if (tmp->tail == i_max)
tmp->tail = 0;
else {
tmp->inbuf[0] = tmp->inbuf[tmp->tail];
tmp->tail = 1;
}
return &tmp->f;
}
/*
* AdpcmToLin_Sample
*/
static struct ast_frame *adpcmtolin_sample(void)
{
static struct ast_frame f;
f.frametype = AST_FRAME_VOICE;
f.subclass = AST_FORMAT_ADPCM;
f.datalen = sizeof(adpcm_slin_ex);
f.samples = sizeof(adpcm_slin_ex) * 2;
f.mallocd = 0;
f.offset = 0;
f.src = __PRETTY_FUNCTION__;
f.data = adpcm_slin_ex;
return &f;
}
/*
* LinToAdpcm_Sample
*/
static struct ast_frame *lintoadpcm_sample(void)
{
static struct ast_frame f;
f.frametype = AST_FRAME_VOICE;
f.subclass = AST_FORMAT_SLINEAR;
f.datalen = sizeof(slin_adpcm_ex);
/* Assume 8000 Hz */
f.samples = sizeof(slin_adpcm_ex) / 2;
f.mallocd = 0;
f.offset = 0;
f.src = __PRETTY_FUNCTION__;
f.data = slin_adpcm_ex;
return &f;
}
/*
* Adpcm_Destroy
* Destroys a private workspace.
*
* Results:
* It's gone!
*
* Side effects:
* None.
*/
static void adpcm_destroy(struct ast_translator_pvt *pvt)
{
free(pvt);
localusecnt--;
ast_update_use_count();
}
/*
* The complete translator for ADPCMToLin.
*/
static struct ast_translator adpcmtolin = {
"adpcmtolin",
AST_FORMAT_ADPCM,
AST_FORMAT_SLINEAR,
adpcmtolin_new,
adpcmtolin_framein,
adpcmtolin_frameout,
adpcm_destroy,
/* NULL */
adpcmtolin_sample
};
/*
* The complete translator for LinToADPCM.
*/
static struct ast_translator lintoadpcm = {
"lintoadpcm",
AST_FORMAT_SLINEAR,
AST_FORMAT_ADPCM,
lintoadpcm_new,
lintoadpcm_framein,
lintoadpcm_frameout,
adpcm_destroy,
/* NULL */
lintoadpcm_sample
};
static void parse_config(void)
{
struct ast_config *cfg;
struct ast_variable *var;
if ((cfg = ast_config_load("codecs.conf"))) {
if ((var = ast_variable_browse(cfg, "plc"))) {
while (var) {
if (!strcasecmp(var->name, "genericplc")) {
useplc = ast_true(var->value) ? 1 : 0;
if (option_verbose > 2)
ast_verbose(VERBOSE_PREFIX_3 "codec_adpcm: %susing generic PLC\n", useplc ? "" : "not ");
}
var = var->next;
}
}
ast_config_destroy(cfg);
}
}
int reload(void)
{
parse_config();
return 0;
}
int unload_module(void)
{
int res;
ast_mutex_lock(&localuser_lock);
res = ast_unregister_translator(&lintoadpcm);
if (!res)
res = ast_unregister_translator(&adpcmtolin);
if (localusecnt)
res = -1;
ast_mutex_unlock(&localuser_lock);
return res;
}
int load_module(void)
{
int res;
parse_config();
res = ast_register_translator(&adpcmtolin);
if (!res)
res = ast_register_translator(&lintoadpcm);
else
ast_unregister_translator(&adpcmtolin);
return res;
}
/*
* Return a description of this module.
*/
char *description(void)
{
return tdesc;
}
int usecount(void)
{
int res;
OLD_STANDARD_USECOUNT(res);
return res;
}
char *key()
{
return ASTERISK_GPL_KEY;
}