Thu Oct 11 06:43:18 2012

Asterisk developer's documentation


codec_lpc10.c File Reference

Translate between signed linear and LPC10 (Linear Predictor Code). More...

#include "asterisk.h"
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <netinet/in.h>
#include <string.h>
#include <stdio.h>
#include "asterisk/lock.h"
#include "asterisk/translate.h"
#include "asterisk/config.h"
#include "asterisk/options.h"
#include "asterisk/module.h"
#include "asterisk/logger.h"
#include "asterisk/channel.h"
#include "asterisk/utils.h"
#include "lpc10/lpc10.h"
#include "slin_lpc10_ex.h"
#include "lpc10_slin_ex.h"

Include dependency graph for codec_lpc10.c:

Go to the source code of this file.

Data Structures

struct  lpc10_coder_pvt

Defines

#define BUFFER_SAMPLES   8000
#define LPC10_BYTES_IN_COMPRESSED_FRAME   (LPC10_BITS_IN_COMPRESSED_FRAME + 7)/8

Functions

static void __reg_module (void)
static void __unreg_module (void)
static void build_bits (unsigned char *c, INT32 *bits)
static void extract_bits (INT32 *bits, unsigned char *c)
static int lintolpc10_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
static struct ast_framelintolpc10_frameout (struct ast_trans_pvt *pvt)
static struct ast_framelintolpc10_sample (void)
static int load_module (void)
static int lpc10_dec_new (struct ast_trans_pvt *pvt)
static void lpc10_destroy (struct ast_trans_pvt *arg)
static int lpc10_enc_new (struct ast_trans_pvt *pvt)
static int lpc10tolin_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
static struct ast_framelpc10tolin_sample (void)
static int reload (void)
static int unload_module (void)

Variables

static struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT | AST_MODFLAG_BUILDSUM, .description = "LPC10 2.4kbps 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, .load = load_module, .unload = unload_module, .reload = reload, }
static const struct
ast_module_info
ast_module_info = &__mod_info
static struct ast_translator lintolpc10
static struct ast_translator lpc10tolin


Detailed Description

Translate between signed linear and LPC10 (Linear Predictor Code).

Definition in file codec_lpc10.c.


Define Documentation

#define BUFFER_SAMPLES   8000

Definition at line 63 of file codec_lpc10.c.

#define LPC10_BYTES_IN_COMPRESSED_FRAME   (LPC10_BITS_IN_COMPRESSED_FRAME + 7)/8

Definition at line 61 of file codec_lpc10.c.

Referenced by lintolpc10_frameout(), and lpc10tolin_framein().


Function Documentation

static void __reg_module ( void   )  [static]

Definition at line 296 of file codec_lpc10.c.

static void __unreg_module ( void   )  [static]

Definition at line 296 of file codec_lpc10.c.

static void build_bits ( unsigned char *  c,
INT32 *  bits 
) [static]

Definition at line 134 of file codec_lpc10.c.

Referenced by lintolpc10_frameout().

00135 {
00136    unsigned char mask=0x80;
00137    int x;
00138    *c = 0;
00139    for (x=0;x<LPC10_BITS_IN_COMPRESSED_FRAME;x++) {
00140       if (bits[x])
00141          *c |= mask;
00142       mask = mask >> 1;
00143       if ((x % 8)==7) {
00144          c++;
00145          *c = 0;
00146          mask = 0x80;
00147       }
00148    }
00149 }

static void extract_bits ( INT32 *  bits,
unsigned char *  c 
) [static]

Definition at line 120 of file codec_lpc10.c.

Referenced by lpc10tolin_framein().

00121 {
00122    int x;
00123    for (x=0;x<LPC10_BITS_IN_COMPRESSED_FRAME;x++) {
00124       if (*c & (0x80 >> (x & 7)))
00125          bits[x] = 1;
00126       else
00127          bits[x] = 0;
00128       if ((x & 7) == 7)
00129          c++;
00130    }
00131 }

static int lintolpc10_framein ( struct ast_trans_pvt pvt,
struct ast_frame f 
) [static]

Definition at line 184 of file codec_lpc10.c.

References ast_log(), lpc10_coder_pvt::buf, BUFFER_SAMPLES, ast_frame::data, ast_frame::datalen, LOG_WARNING, ast_trans_pvt::pvt, ast_frame::samples, and ast_trans_pvt::samples.

00185 {
00186    struct lpc10_coder_pvt *tmp = pvt->pvt;
00187 
00188    /* Just add the frames to our stream */
00189    if (pvt->samples + f->samples > BUFFER_SAMPLES) {
00190       ast_log(LOG_WARNING, "Out of buffer space\n");
00191       return -1;
00192    }
00193    memcpy(tmp->buf + pvt->samples, f->data, f->datalen);
00194    pvt->samples += f->samples;
00195    return 0;
00196 }

static struct ast_frame* lintolpc10_frameout ( struct ast_trans_pvt pvt  )  [static, read]

Definition at line 198 of file codec_lpc10.c.

References ast_trans_frameout(), lpc10_coder_pvt::buf, build_bits(), lpc10_coder_pvt::enc, lpc10_coder_pvt::longer, lpc10_coder_pvt::lpc10, LPC10_BYTES_IN_COMPRESSED_FRAME, ast_trans_pvt::outbuf, ast_trans_pvt::pvt, and ast_trans_pvt::samples.

00199 {
00200    struct lpc10_coder_pvt *tmp = pvt->pvt;
00201    int x;
00202    int datalen = 0;  /* output frame */
00203    int samples = 0;  /* output samples */
00204    float tmpbuf[LPC10_SAMPLES_PER_FRAME];
00205    INT32 bits[LPC10_BITS_IN_COMPRESSED_FRAME];  /* XXX what ??? */
00206    /* We can't work on anything less than a frame in size */
00207    if (pvt->samples < LPC10_SAMPLES_PER_FRAME)
00208       return NULL;
00209    while (pvt->samples >=  LPC10_SAMPLES_PER_FRAME) {
00210       /* Encode a frame of data */
00211       for (x=0;x<LPC10_SAMPLES_PER_FRAME;x++)
00212          tmpbuf[x] = (float)tmp->buf[x + samples] / 32768.0;
00213       lpc10_encode(tmpbuf, bits, tmp->lpc10.enc);
00214       build_bits((unsigned char *) pvt->outbuf + datalen, bits);
00215       datalen += LPC10_BYTES_IN_COMPRESSED_FRAME;
00216       samples += LPC10_SAMPLES_PER_FRAME;
00217       pvt->samples -= LPC10_SAMPLES_PER_FRAME;
00218       /* Use one of the two left over bits to record if this is a 22 or 23 ms frame...
00219          important for IAX use */
00220       tmp->longer = 1 - tmp->longer;
00221    }
00222    /* Move the data at the end of the buffer to the front */
00223    if (pvt->samples)
00224       memmove(tmp->buf, tmp->buf + samples, pvt->samples * 2);
00225    return ast_trans_frameout(pvt, datalen, samples);
00226 }

static struct ast_frame* lintolpc10_sample ( void   )  [static, read]

Definition at line 89 of file codec_lpc10.c.

References AST_FORMAT_SLINEAR, AST_FRAME_VOICE, ast_frame::data, ast_frame::datalen, ast_frame::frametype, ast_frame::mallocd, ast_frame::offset, ast_frame::samples, slin_lpc10_ex, ast_frame::src, and ast_frame::subclass.

00090 {
00091    static struct ast_frame f;
00092    f.frametype = AST_FRAME_VOICE;
00093    f.subclass = AST_FORMAT_SLINEAR;
00094    f.datalen = sizeof(slin_lpc10_ex);
00095    /* Assume 8000 Hz */
00096    f.samples = LPC10_SAMPLES_PER_FRAME;
00097    f.mallocd = 0;
00098    f.offset = 0;
00099    f.src = __PRETTY_FUNCTION__;
00100    f.data = slin_lpc10_ex;
00101    return &f;
00102 }

static int load_module ( void   )  [static]

Definition at line 279 of file codec_lpc10.c.

References ast_register_translator, and ast_unregister_translator().

00280 {
00281    int res;
00282 
00283    res=ast_register_translator(&lpc10tolin);
00284    if (!res) 
00285       res=ast_register_translator(&lintolpc10);
00286    else
00287       ast_unregister_translator(&lpc10tolin);
00288 
00289    return res;
00290 }

static int lpc10_dec_new ( struct ast_trans_pvt pvt  )  [static]

Definition at line 82 of file codec_lpc10.c.

References lpc10_coder_pvt::dec, lpc10_coder_pvt::lpc10, and ast_trans_pvt::pvt.

00083 {
00084    struct lpc10_coder_pvt *tmp = pvt->pvt;
00085 
00086    return (tmp->lpc10.dec = create_lpc10_decoder_state()) ? 0 : -1;
00087 }

static void lpc10_destroy ( struct ast_trans_pvt arg  )  [static]

Definition at line 229 of file codec_lpc10.c.

References lpc10_coder_pvt::enc, free, lpc10_coder_pvt::lpc10, and ast_trans_pvt::pvt.

00230 {
00231    struct lpc10_coder_pvt *pvt = arg->pvt;
00232    /* Enc and DEC are both just allocated, so they can be freed */
00233    free(pvt->lpc10.enc);
00234 }

static int lpc10_enc_new ( struct ast_trans_pvt pvt  )  [static]

Definition at line 75 of file codec_lpc10.c.

References lpc10_coder_pvt::enc, lpc10_coder_pvt::lpc10, and ast_trans_pvt::pvt.

00076 {
00077    struct lpc10_coder_pvt *tmp = pvt->pvt;
00078 
00079    return (tmp->lpc10.enc = create_lpc10_encoder_state()) ? 0 : -1;
00080 }

static int lpc10tolin_framein ( struct ast_trans_pvt pvt,
struct ast_frame f 
) [static]

Definition at line 151 of file codec_lpc10.c.

References ast_log(), BUFFER_SAMPLES, ast_frame::data, ast_frame::datalen, ast_trans_pvt::datalen, lpc10_coder_pvt::dec, extract_bits(), len(), LOG_WARNING, lpc10_coder_pvt::lpc10, LPC10_BYTES_IN_COMPRESSED_FRAME, ast_trans_pvt::outbuf, ast_trans_pvt::pvt, and ast_trans_pvt::samples.

00152 {
00153    struct lpc10_coder_pvt *tmp = pvt->pvt;
00154    int16_t *dst = (int16_t *)pvt->outbuf;
00155    int len = 0;
00156 
00157    while (len + LPC10_BYTES_IN_COMPRESSED_FRAME <= f->datalen) {
00158       int x;
00159       float tmpbuf[LPC10_SAMPLES_PER_FRAME];
00160       INT32 bits[LPC10_BITS_IN_COMPRESSED_FRAME]; /* XXX see note */
00161       if (pvt->samples + LPC10_SAMPLES_PER_FRAME > BUFFER_SAMPLES) {
00162          ast_log(LOG_WARNING, "Out of buffer space\n");
00163          return -1;
00164       }
00165       extract_bits(bits, f->data + len);
00166       if (lpc10_decode(bits, tmpbuf, tmp->lpc10.dec)) {
00167          ast_log(LOG_WARNING, "Invalid lpc10 data\n");
00168          return -1;
00169       }
00170       for (x=0;x<LPC10_SAMPLES_PER_FRAME;x++) {
00171          /* Convert to a short between -1.0 and 1.0 */
00172          dst[pvt->samples + x] = (int16_t)(32768.0 * tmpbuf[x]);
00173       }
00174 
00175       pvt->samples += LPC10_SAMPLES_PER_FRAME;
00176       pvt->datalen += 2*LPC10_SAMPLES_PER_FRAME;
00177       len += LPC10_BYTES_IN_COMPRESSED_FRAME;
00178    }
00179    if (len != f->datalen) 
00180       printf("Decoded %d, expected %d\n", len, f->datalen);
00181    return 0;
00182 }

static struct ast_frame* lpc10tolin_sample ( void   )  [static, read]

Definition at line 104 of file codec_lpc10.c.

References AST_FORMAT_LPC10, AST_FRAME_VOICE, ast_frame::data, ast_frame::datalen, ast_frame::frametype, lpc10_slin_ex, ast_frame::mallocd, ast_frame::offset, ast_frame::samples, ast_frame::src, and ast_frame::subclass.

00105 {
00106    static struct ast_frame f;
00107    f.frametype = AST_FRAME_VOICE;
00108    f.subclass = AST_FORMAT_LPC10;
00109    f.datalen = sizeof(lpc10_slin_ex);
00110    /* All frames are 22 ms long (maybe a little more -- why did he choose
00111       LPC10_SAMPLES_PER_FRAME sample frames anyway?? */
00112    f.samples = LPC10_SAMPLES_PER_FRAME;
00113    f.mallocd = 0;
00114    f.offset = 0;
00115    f.src = __PRETTY_FUNCTION__;
00116    f.data = lpc10_slin_ex;
00117    return &f;
00118 }

static int reload ( void   )  [static]

Definition at line 263 of file codec_lpc10.c.

00264 {
00265         return 0;
00266 }

static int unload_module ( void   )  [static]

Definition at line 269 of file codec_lpc10.c.

References ast_unregister_translator().

00270 {
00271    int res;
00272 
00273    res = ast_unregister_translator(&lintolpc10);
00274    res |= ast_unregister_translator(&lpc10tolin);
00275 
00276    return res;
00277 }


Variable Documentation

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT | AST_MODFLAG_BUILDSUM, .description = "LPC10 2.4kbps 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, .load = load_module, .unload = unload_module, .reload = reload, } [static]

Definition at line 296 of file codec_lpc10.c.

const struct ast_module_info* ast_module_info = &__mod_info [static]

Definition at line 296 of file codec_lpc10.c.

struct ast_translator lintolpc10 [static]

Definition at line 249 of file codec_lpc10.c.

struct ast_translator lpc10tolin [static]

Definition at line 236 of file codec_lpc10.c.


Generated on Thu Oct 11 06:43:19 2012 for Asterisk - the Open Source PBX by  doxygen 1.5.6