codec_lpc10.c File Reference

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

#include "asterisk.h"
#include "asterisk/translate.h"
#include "asterisk/config.h"
#include "asterisk/module.h"
#include "asterisk/utils.h"
#include "lpc10/lpc10.h"
#include "asterisk/slin.h"
#include "ex_lpc10.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 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 int unload_module (void)

Variables

static struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .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, .support_level = AST_MODULE_SUPPORT_CORE, .load = load_module, .unload = unload_module, }
static struct ast_module_infoast_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 56 of file codec_lpc10.c.

#define LPC10_BYTES_IN_COMPRESSED_FRAME   (LPC10_BITS_IN_COMPRESSED_FRAME + 7)/8

Definition at line 54 of file codec_lpc10.c.

Referenced by lintolpc10_frameout(), and lpc10tolin_framein().


Function Documentation

static void __reg_module ( void   )  [static]

Definition at line 272 of file codec_lpc10.c.

static void __unreg_module ( void   )  [static]

Definition at line 272 of file codec_lpc10.c.

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

Definition at line 96 of file codec_lpc10.c.

References LPC10_BITS_IN_COMPRESSED_FRAME.

Referenced by lintolpc10_frameout().

00097 {
00098    unsigned char mask=0x80;
00099    int x;
00100    *c = 0;
00101    for (x=0;x<LPC10_BITS_IN_COMPRESSED_FRAME;x++) {
00102       if (bits[x])
00103          *c |= mask;
00104       mask = mask >> 1;
00105       if ((x % 8)==7) {
00106          c++;
00107          *c = 0;
00108          mask = 0x80;
00109       }
00110    }
00111 }

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

Definition at line 82 of file codec_lpc10.c.

References LPC10_BITS_IN_COMPRESSED_FRAME.

Referenced by lpc10tolin_framein().

00083 {
00084    int x;
00085    for (x=0;x<LPC10_BITS_IN_COMPRESSED_FRAME;x++) {
00086       if (*c & (0x80 >> (x & 7)))
00087          bits[x] = 1;
00088       else
00089          bits[x] = 0;
00090       if ((x & 7) == 7)
00091          c++;
00092    }
00093 }

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

Definition at line 146 of file codec_lpc10.c.

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

00147 {
00148    struct lpc10_coder_pvt *tmp = pvt->pvt;
00149 
00150    /* Just add the frames to our stream */
00151    if (pvt->samples + f->samples > BUFFER_SAMPLES) {
00152       ast_log(LOG_WARNING, "Out of buffer space\n");
00153       return -1;
00154    }
00155    memcpy(tmp->buf + pvt->samples, f->data.ptr, f->datalen);
00156    pvt->samples += f->samples;
00157    return 0;
00158 }

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

Definition at line 160 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_BITS_IN_COMPRESSED_FRAME, LPC10_BYTES_IN_COMPRESSED_FRAME, lpc10_encode(), LPC10_SAMPLES_PER_FRAME, NULL, ast_trans_pvt::outbuf, ast_trans_pvt::pvt, ast_trans_pvt::samples, tmp(), and ast_trans_pvt::uc.

00161 {
00162    struct lpc10_coder_pvt *tmp = pvt->pvt;
00163    int x;
00164    int datalen = 0;  /* output frame */
00165    int samples = 0;  /* output samples */
00166    float tmpbuf[LPC10_SAMPLES_PER_FRAME];
00167    INT32 bits[LPC10_BITS_IN_COMPRESSED_FRAME];  /* XXX what ??? */
00168    /* We can't work on anything less than a frame in size */
00169    if (pvt->samples < LPC10_SAMPLES_PER_FRAME)
00170       return NULL;
00171    while (pvt->samples >=  LPC10_SAMPLES_PER_FRAME) {
00172       /* Encode a frame of data */
00173       for (x=0;x<LPC10_SAMPLES_PER_FRAME;x++)
00174          tmpbuf[x] = (float)tmp->buf[x + samples] / 32768.0;
00175       lpc10_encode(tmpbuf, bits, tmp->lpc10.enc);
00176       build_bits(pvt->outbuf.uc + datalen, bits);
00177       datalen += LPC10_BYTES_IN_COMPRESSED_FRAME;
00178       samples += LPC10_SAMPLES_PER_FRAME;
00179       pvt->samples -= LPC10_SAMPLES_PER_FRAME;
00180       /* Use one of the two left over bits to record if this is a 22 or 23 ms frame...
00181          important for IAX use */
00182       tmp->longer = 1 - tmp->longer;
00183    }
00184    /* Move the data at the end of the buffer to the front */
00185    if (pvt->samples)
00186       memmove(tmp->buf, tmp->buf + samples, pvt->samples * 2);
00187    return ast_trans_frameout(pvt, datalen, samples);
00188 }

static int load_module ( void   )  [static]

Definition at line 253 of file codec_lpc10.c.

References AST_MODULE_LOAD_FAILURE, AST_MODULE_LOAD_SUCCESS, ast_register_translator, and unload_module.

00254 {
00255    int res;
00256 
00257    res = ast_register_translator(&lpc10tolin);
00258    res |= ast_register_translator(&lintolpc10);
00259 
00260    if (res) {
00261       unload_module();
00262       return AST_MODULE_LOAD_FAILURE;
00263    }
00264 
00265    return AST_MODULE_LOAD_SUCCESS;
00266 }

static int lpc10_dec_new ( struct ast_trans_pvt pvt  )  [static]

Definition at line 75 of file codec_lpc10.c.

References create_lpc10_decoder_state(), lpc10_coder_pvt::dec, lpc10_coder_pvt::lpc10, ast_trans_pvt::pvt, and tmp().

00076 {
00077    struct lpc10_coder_pvt *tmp = pvt->pvt;
00078 
00079    return (tmp->lpc10.dec = create_lpc10_decoder_state()) ? 0 : -1;
00080 }

static void lpc10_destroy ( struct ast_trans_pvt arg  )  [static]

Definition at line 191 of file codec_lpc10.c.

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

00192 {
00193    struct lpc10_coder_pvt *pvt = arg->pvt;
00194    /* Enc and DEC are both just allocated, so they can be freed */
00195    ast_free(pvt->lpc10.enc);
00196 }

static int lpc10_enc_new ( struct ast_trans_pvt pvt  )  [static]

Definition at line 68 of file codec_lpc10.c.

References create_lpc10_encoder_state(), lpc10_coder_pvt::enc, lpc10_coder_pvt::lpc10, ast_trans_pvt::pvt, and tmp().

00069 {
00070    struct lpc10_coder_pvt *tmp = pvt->pvt;
00071 
00072    return (tmp->lpc10.enc = create_lpc10_encoder_state()) ? 0 : -1;
00073 }

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

Definition at line 113 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(), ast_trans_pvt::i16, len(), LOG_WARNING, lpc10_coder_pvt::lpc10, LPC10_BITS_IN_COMPRESSED_FRAME, LPC10_BYTES_IN_COMPRESSED_FRAME, lpc10_decode(), LPC10_SAMPLES_PER_FRAME, ast_trans_pvt::outbuf, ast_frame::ptr, ast_trans_pvt::pvt, ast_trans_pvt::samples, and tmp().

00114 {
00115    struct lpc10_coder_pvt *tmp = pvt->pvt;
00116    int16_t *dst = pvt->outbuf.i16;
00117    int len = 0;
00118 
00119    while (len + LPC10_BYTES_IN_COMPRESSED_FRAME <= f->datalen) {
00120       int x;
00121       float tmpbuf[LPC10_SAMPLES_PER_FRAME];
00122       INT32 bits[LPC10_BITS_IN_COMPRESSED_FRAME]; /* XXX see note */
00123       if (pvt->samples + LPC10_SAMPLES_PER_FRAME > BUFFER_SAMPLES) {
00124          ast_log(LOG_WARNING, "Out of buffer space\n");
00125          return -1;
00126       }
00127       extract_bits(bits, f->data.ptr + len);
00128       if (lpc10_decode(bits, tmpbuf, tmp->lpc10.dec)) {
00129          ast_log(LOG_WARNING, "Invalid lpc10 data\n");
00130          return -1;
00131       }
00132       for (x=0;x<LPC10_SAMPLES_PER_FRAME;x++) {
00133          /* Convert to a short between -1.0 and 1.0 */
00134          dst[pvt->samples + x] = (int16_t)(32768.0 * tmpbuf[x]);
00135       }
00136 
00137       pvt->samples += LPC10_SAMPLES_PER_FRAME;
00138       pvt->datalen += 2*LPC10_SAMPLES_PER_FRAME;
00139       len += LPC10_BYTES_IN_COMPRESSED_FRAME;
00140    }
00141    if (len != f->datalen) 
00142       printf("Decoded %d, expected %d\n", len, f->datalen);
00143    return 0;
00144 }

static int unload_module ( void   )  [static]

Definition at line 243 of file codec_lpc10.c.

References ast_unregister_translator().

00244 {
00245    int res;
00246 
00247    res = ast_unregister_translator(&lintolpc10);
00248    res |= ast_unregister_translator(&lpc10tolin);
00249 
00250    return res;
00251 }


Variable Documentation

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .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, .support_level = AST_MODULE_SUPPORT_CORE, .load = load_module, .unload = unload_module, } [static]

Definition at line 272 of file codec_lpc10.c.

Definition at line 272 of file codec_lpc10.c.

struct ast_translator lintolpc10 [static]

Definition at line 220 of file codec_lpc10.c.

struct ast_translator lpc10tolin [static]

Definition at line 198 of file codec_lpc10.c.


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