Asterisk - The Open Source Telephony Project GIT-master-55f4e6d
Data Structures | Macros | Functions | Variables
codec_adpcm.c File Reference

codec_adpcm.c - translate between signed linear and Dialogic ADPCM 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 "asterisk/slin.h"
#include "ex_adpcm.h"
Include dependency graph for codec_adpcm.c:

Go to the source code of this file.

Data Structures

struct  adpcm_decoder_pvt
 Workspace for translating ADPCM signals to signed linear. More...
 
struct  adpcm_encoder_pvt
 Workspace for translating signed linear signals to ADPCM. More...
 
struct  adpcm_state
 

Macros

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

Functions

static void __reg_module (void)
 
static void __unreg_module (void)
 
static int adpcm (short csig, struct adpcm_state *state)
 
static int adpcmtolin_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
 decode 4-bit adpcm frame data and store in output buffer More...
 
struct ast_moduleAST_MODULE_SELF_SYM (void)
 
static short decode (int encoded, struct adpcm_state *state)
 
static int lintoadpcm_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
 fill input buffer with 16-bit signed linear PCM values. More...
 
static struct ast_framelintoadpcm_frameout (struct ast_trans_pvt *pvt)
 convert inbuf and store into frame More...
 
static int load_module (void)
 
static int unload_module (void)
 

Variables

static struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "Adaptive Differential PCM Coder/Decoder" , .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, .support_level = AST_MODULE_SUPPORT_CORE, .load = load_module, .unload = unload_module, }
 
static struct ast_translator adpcmtolin
 
static const struct ast_module_infoast_module_info = &__mod_info
 
static int indsft [8] = { -1, -1, -1, -1, 2, 4, 6, 8 }
 
static struct ast_translator lintoadpcm
 
static int stpsz [49]
 

Detailed Description

codec_adpcm.c - translate between signed linear and Dialogic ADPCM

Definition in file codec_adpcm.c.

Macro Definition Documentation

◆ BUFFER_SAMPLES

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

Definition at line 46 of file codec_adpcm.c.

Function Documentation

◆ __reg_module()

static void __reg_module ( void  )
static

Definition at line 359 of file codec_adpcm.c.

◆ __unreg_module()

static void __unreg_module ( void  )
static

Definition at line 359 of file codec_adpcm.c.

◆ adpcm()

static int adpcm ( short  csig,
struct adpcm_state state 
)
inlinestatic

Definition at line 164 of file codec_adpcm.c.

165{
166 int diff;
167 int step;
168 int encoded;
169
170 /*
171 * Clip csig if too large or too small
172 */
173 csig >>= 4;
174
175 step = stpsz[state->ssindex];
176 diff = csig - state->signal;
177
178#ifdef NOT_BLI
179 if (diff < 0) {
180 encoded = (-diff << 2) / step;
181 if (encoded > 7)
182 encoded = 7;
183 encoded |= 0x08;
184 } else {
185 encoded = (diff << 2) / step;
186 if (encoded > 7)
187 encoded = 7;
188 }
189#else /* BLI code */
190 if (diff < 0) {
191 encoded = 8;
192 diff = -diff;
193 } else
194 encoded = 0;
195 if (diff >= step) {
196 encoded |= 4;
197 diff -= step;
198 }
199 step >>= 1;
200 if (diff >= step) {
201 encoded |= 2;
202 diff -= step;
203 }
204 step >>= 1;
205 if (diff >= step)
206 encoded |= 1;
207#endif /* NOT_BLI */
208
209 /* feedback to state */
210 decode(encoded, state);
211
212 return encoded;
213}
static int stpsz[49]
Definition: codec_adpcm.c:62
static short decode(int encoded, struct adpcm_state *state)
Definition: codec_adpcm.c:91

References decode(), and stpsz.

Referenced by lintoadpcm_frameout().

◆ adpcmtolin_framein()

static int adpcmtolin_framein ( struct ast_trans_pvt pvt,
struct ast_frame f 
)
static

decode 4-bit adpcm frame data and store in output buffer

Definition at line 229 of file codec_adpcm.c.

230{
231 struct adpcm_decoder_pvt *tmp = pvt->pvt;
232 int x = f->datalen;
233 unsigned char *src = f->data.ptr;
234 int16_t *dst = pvt->outbuf.i16 + pvt->samples;
235
236 while (x--) {
237 *dst++ = decode((*src >> 4) & 0xf, &tmp->state);
238 *dst++ = decode(*src++ & 0x0f, &tmp->state);
239 }
240 pvt->samples += f->samples;
241 pvt->datalen += 2*f->samples;
242 return 0;
243}
static int tmp()
Definition: bt_open.c:389
short int16_t
Definition: db.h:59
Workspace for translating ADPCM signals to signed linear.
Definition: codec_adpcm.c:224
union ast_frame::@226 data
void * pvt
Definition: translate.h:219
int datalen
actual space used in outbuf
Definition: translate.h:218
union ast_trans_pvt::@287 outbuf
int16_t * i16
Definition: translate.h:223

References ast_frame::data, ast_frame::datalen, ast_trans_pvt::datalen, decode(), ast_trans_pvt::i16, ast_trans_pvt::outbuf, ast_frame::ptr, ast_trans_pvt::pvt, ast_frame::samples, ast_trans_pvt::samples, and tmp().

◆ AST_MODULE_SELF_SYM()

struct ast_module * AST_MODULE_SELF_SYM ( void  )

Definition at line 359 of file codec_adpcm.c.

◆ decode()

static short decode ( int  encoded,
struct adpcm_state state 
)
inlinestatic

Definition at line 91 of file codec_adpcm.c.

92{
93 int diff;
94 int step;
95 int sign;
96
97 step = stpsz[state->ssindex];
98
99 sign = encoded & 0x08;
100 encoded &= 0x07;
101#ifdef NOT_BLI
102 diff = (((encoded << 1) + 1) * step) >> 3;
103#else /* BLI code */
104 diff = step >> 3;
105 if (encoded & 4)
106 diff += step;
107 if (encoded & 2)
108 diff += step >> 1;
109 if (encoded & 1)
110 diff += step >> 2;
111 if ((encoded >> 1) & step & 0x1)
112 diff++;
113#endif
114 if (sign)
115 diff = -diff;
116
117 if (state->next_flag & 0x1)
118 state->signal -= 8;
119 else if (state->next_flag & 0x2)
120 state->signal += 8;
121
122 state->signal += diff;
123
124 if (state->signal > 2047)
125 state->signal = 2047;
126 else if (state->signal < -2047)
127 state->signal = -2047;
128
129 state->next_flag = 0;
130
131#ifdef AUTO_RETURN
132 if (encoded)
133 state->zero_count = 0;
134 else if (++(state->zero_count) == 24) {
135 state->zero_count = 0;
136 if (state->signal > 0)
137 state->next_flag = 0x1;
138 else if (state->signal < 0)
139 state->next_flag = 0x2;
140 }
141#endif
142
143 state->ssindex += indsft[encoded];
144 if (state->ssindex < 0)
145 state->ssindex = 0;
146 else if (state->ssindex > 48)
147 state->ssindex = 48;
148
149 return state->signal << 4;
150}
static int indsft[8]
Definition: codec_adpcm.c:56

References indsft, and stpsz.

Referenced by adpcm(), and adpcmtolin_framein().

◆ lintoadpcm_framein()

static int lintoadpcm_framein ( struct ast_trans_pvt pvt,
struct ast_frame f 
)
static

fill input buffer with 16-bit signed linear PCM values.

Definition at line 246 of file codec_adpcm.c.

247{
248 struct adpcm_encoder_pvt *tmp = pvt->pvt;
249
250 memcpy(&tmp->inbuf[pvt->samples], f->data.ptr, f->datalen);
251 pvt->samples += f->samples;
252 return 0;
253}
Workspace for translating signed linear signals to ADPCM.
Definition: codec_adpcm.c:218

References ast_frame::data, ast_frame::datalen, ast_frame::ptr, ast_trans_pvt::pvt, ast_frame::samples, ast_trans_pvt::samples, and tmp().

◆ lintoadpcm_frameout()

static struct ast_frame * lintoadpcm_frameout ( struct ast_trans_pvt pvt)
static

convert inbuf and store into frame

Definition at line 256 of file codec_adpcm.c.

257{
258 struct adpcm_encoder_pvt *tmp = pvt->pvt;
259 struct ast_frame *f;
260 int i;
261 int samples = pvt->samples; /* save original number */
262
263 if (samples < 2)
264 return NULL;
265
266 pvt->samples &= ~1; /* atomic size is 2 samples */
267
268 for (i = 0; i < pvt->samples; i += 2) {
269 pvt->outbuf.c[i/2] =
270 (adpcm(tmp->inbuf[i ], &tmp->state) << 4) |
271 (adpcm(tmp->inbuf[i+1], &tmp->state) );
272 };
273
274 f = ast_trans_frameout(pvt, pvt->samples/2, 0);
275
276 /*
277 * If there is a left over sample, move it to the beginning
278 * of the input buffer.
279 */
280
281 if (samples & 1) { /* move the leftover sample at beginning */
282 tmp->inbuf[0] = tmp->inbuf[samples - 1];
283 pvt->samples = 1;
284 }
285 return f;
286}
static int adpcm(short csig, struct adpcm_state *state)
Definition: codec_adpcm.c:164
#define NULL
Definition: resample.c:96
Data structure associated with a single frame of data.
struct ast_frame * ast_trans_frameout(struct ast_trans_pvt *pvt, int datalen, int samples)
generic frameout function
Definition: translate.c:439

References adpcm(), ast_trans_frameout(), ast_trans_pvt::c, NULL, ast_trans_pvt::outbuf, ast_trans_pvt::pvt, ast_frame::samples, ast_trans_pvt::samples, and tmp().

◆ load_module()

static int load_module ( void  )
static

Definition at line 340 of file codec_adpcm.c.

341{
342 int res = 0;
343
346
347 if (res) {
350 }
351
353}
static struct ast_translator adpcmtolin
Definition: codec_adpcm.c:289
static struct ast_translator lintoadpcm
Definition: codec_adpcm.c:309
static int unload_module(void)
Definition: codec_adpcm.c:330
@ AST_MODULE_LOAD_SUCCESS
Definition: module.h:70
@ AST_MODULE_LOAD_DECLINE
Module has failed to load, may be in an inconsistent state.
Definition: module.h:78
#define ast_register_translator(t)
See __ast_register_translator()
Definition: translate.h:258

References adpcmtolin, AST_MODULE_LOAD_DECLINE, AST_MODULE_LOAD_SUCCESS, ast_register_translator, lintoadpcm, and unload_module().

◆ unload_module()

static int unload_module ( void  )
static

Definition at line 330 of file codec_adpcm.c.

331{
332 int res;
333
336
337 return res;
338}
int ast_unregister_translator(struct ast_translator *t)
Unregister a translator Unregisters the given translator.
Definition: translate.c:1350

References adpcmtolin, ast_unregister_translator(), and lintoadpcm.

Referenced by load_module().

Variable Documentation

◆ __mod_info

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "Adaptive Differential PCM Coder/Decoder" , .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, .support_level = AST_MODULE_SUPPORT_CORE, .load = load_module, .unload = unload_module, }
static

Definition at line 359 of file codec_adpcm.c.

◆ adpcmtolin

struct ast_translator adpcmtolin
static

Definition at line 289 of file codec_adpcm.c.

Referenced by load_module(), and unload_module().

◆ ast_module_info

const struct ast_module_info* ast_module_info = &__mod_info
static

Definition at line 359 of file codec_adpcm.c.

◆ indsft

int indsft[8] = { -1, -1, -1, -1, 2, 4, 6, 8 }
static

Definition at line 56 of file codec_adpcm.c.

Referenced by decode().

◆ lintoadpcm

struct ast_translator lintoadpcm
static

Definition at line 309 of file codec_adpcm.c.

Referenced by load_module(), and unload_module().

◆ stpsz

int stpsz[49]
static

Definition at line 62 of file codec_adpcm.c.

Referenced by adpcm(), and decode().