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_frame *	lintolpc10_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	reload (void)
static int	unload_module (void)
Variables
static struct ast_module_info __MODULE_INFO_SECTION	__mod_info = { __MODULE_INFO_GLOBALS .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "LPC10 2.4kbps Coder/Decoder" , .key = ASTERISK_GPL_KEY , .buildopt_sum = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .reload = reload, }
static 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 52 of file codec_lpc10.c.

Referenced by lintolpc10_framein(), and lpc10tolin_framein().

#define LPC10_BYTES_IN_COMPRESSED_FRAME (LPC10_BITS_IN_COMPRESSED_FRAME + 7)/8

Definition at line 50 of file codec_lpc10.c.

Referenced by lintolpc10_frameout(), and lpc10tolin_framein().

Function Documentation

static void __reg_module ( void ) [static]

Definition at line 255 of file codec_lpc10.c.

static void __unreg_module ( void ) [static]

Definition at line 255 of file codec_lpc10.c.

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

Definition at line 92 of file codec_lpc10.c.

Referenced by lintolpc10_frameout().

{
   unsigned char mask=0x80;
   int x;
   *c = 0;
   for (x=0;x<LPC10_BITS_IN_COMPRESSED_FRAME;x++) {
      if (bits[x])
         *c |= mask;
      mask = mask >> 1;
      if ((x % 8)==7) {
         c++;
         *c = 0;
         mask = 0x80;
      }
   }
}

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

Definition at line 78 of file codec_lpc10.c.

Referenced by lpc10tolin_framein().

{
   int x;
   for (x=0;x<LPC10_BITS_IN_COMPRESSED_FRAME;x++) {
      if (*c & (0x80 >> (x & 7)))
         bits[x] = 1;
      else
         bits[x] = 0;
      if ((x & 7) == 7)
         c++;
   }
}

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

Definition at line 142 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, and ast_trans_pvt::samples.

{
   struct lpc10_coder_pvt *tmp = pvt->pvt;

   /* Just add the frames to our stream */
   if (pvt->samples + f->samples > BUFFER_SAMPLES) {
      ast_log(LOG_WARNING, "Out of buffer space\n");
      return -1;
   }
   memcpy(tmp->buf + pvt->samples, f->data.ptr, f->datalen);
   pvt->samples += f->samples;
   return 0;
}

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

Definition at line 156 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, ast_trans_pvt::samples, and ast_trans_pvt::uc.

{
   struct lpc10_coder_pvt *tmp = pvt->pvt;
   int x;
   int datalen = 0;  /* output frame */
   int samples = 0;  /* output samples */
   float tmpbuf[LPC10_SAMPLES_PER_FRAME];
   INT32 bits[LPC10_BITS_IN_COMPRESSED_FRAME];  /* XXX what ??? */
   /* We can't work on anything less than a frame in size */
   if (pvt->samples < LPC10_SAMPLES_PER_FRAME)
      return NULL;
   while (pvt->samples >=  LPC10_SAMPLES_PER_FRAME) {
      /* Encode a frame of data */
      for (x=0;x<LPC10_SAMPLES_PER_FRAME;x++)
         tmpbuf[x] = (float)tmp->buf[x + samples] / 32768.0;
      lpc10_encode(tmpbuf, bits, tmp->lpc10.enc);
      build_bits(pvt->outbuf.uc + datalen, bits);
      datalen += LPC10_BYTES_IN_COMPRESSED_FRAME;
      samples += LPC10_SAMPLES_PER_FRAME;
      pvt->samples -= LPC10_SAMPLES_PER_FRAME;
      /* Use one of the two left over bits to record if this is a 22 or 23 ms frame...
         important for IAX use */
      tmp->longer = 1 - tmp->longer;
   }
   /* Move the data at the end of the buffer to the front */
   if (pvt->samples)
      memmove(tmp->buf, tmp->buf + samples, pvt->samples * 2);
   return ast_trans_frameout(pvt, datalen, samples);
}

static int load_module ( void ) [static]

Definition at line 237 of file codec_lpc10.c.

References AST_MODULE_LOAD_FAILURE, AST_MODULE_LOAD_SUCCESS, ast_register_translator, and ast_unregister_translator().

{
   int res;

   res = ast_register_translator(&lpc10tolin);
   if (!res) 
      res = ast_register_translator(&lintolpc10);
   else
      ast_unregister_translator(&lpc10tolin);
   if (res)
      return AST_MODULE_LOAD_FAILURE;
   return AST_MODULE_LOAD_SUCCESS;
}

static int lpc10_dec_new ( struct ast_trans_pvt * pvt ) [static]

Definition at line 71 of file codec_lpc10.c.

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

{
   struct lpc10_coder_pvt *tmp = pvt->pvt;

   return (tmp->lpc10.dec = create_lpc10_decoder_state()) ? 0 : -1;
}

static void lpc10_destroy ( struct ast_trans_pvt * arg ) [static]

Definition at line 187 of file codec_lpc10.c.

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

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

static int lpc10_enc_new ( struct ast_trans_pvt * pvt ) [static]

Definition at line 64 of file codec_lpc10.c.

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

{
   struct lpc10_coder_pvt *tmp = pvt->pvt;

   return (tmp->lpc10.enc = create_lpc10_encoder_state()) ? 0 : -1;
}

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

Definition at line 109 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_BYTES_IN_COMPRESSED_FRAME, ast_trans_pvt::outbuf, ast_frame::ptr, ast_trans_pvt::pvt, and ast_trans_pvt::samples.

{
   struct lpc10_coder_pvt *tmp = pvt->pvt;
   int16_t *dst = pvt->outbuf.i16;
   int len = 0;

   while (len + LPC10_BYTES_IN_COMPRESSED_FRAME <= f->datalen) {
      int x;
      float tmpbuf[LPC10_SAMPLES_PER_FRAME];
      INT32 bits[LPC10_BITS_IN_COMPRESSED_FRAME]; /* XXX see note */
      if (pvt->samples + LPC10_SAMPLES_PER_FRAME > BUFFER_SAMPLES) {
         ast_log(LOG_WARNING, "Out of buffer space\n");
         return -1;
      }
      extract_bits(bits, f->data.ptr + len);
      if (lpc10_decode(bits, tmpbuf, tmp->lpc10.dec)) {
         ast_log(LOG_WARNING, "Invalid lpc10 data\n");
         return -1;
      }
      for (x=0;x<LPC10_SAMPLES_PER_FRAME;x++) {
         /* Convert to a short between -1.0 and 1.0 */
         dst[pvt->samples + x] = (int16_t)(32768.0 * tmpbuf[x]);
      }

      pvt->samples += LPC10_SAMPLES_PER_FRAME;
      pvt->datalen += 2*LPC10_SAMPLES_PER_FRAME;
      len += LPC10_BYTES_IN_COMPRESSED_FRAME;
   }
   if (len != f->datalen) 
      printf("Decoded %d, expected %d\n", len, f->datalen);
   return 0;
}

static int reload ( void ) [static]

Definition at line 221 of file codec_lpc10.c.

References AST_MODULE_LOAD_SUCCESS.

{
   return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module ( void ) [static]

Definition at line 227 of file codec_lpc10.c.

References ast_unregister_translator().

{
   int res;

   res = ast_unregister_translator(&lintolpc10);
   res |= ast_unregister_translator(&lpc10tolin);

   return res;
}

Variable Documentation

struct ast_module_info __MODULE_INFO_SECTION __mod_info = { __MODULE_INFO_GLOBALS .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "LPC10 2.4kbps Coder/Decoder" , .key = ASTERISK_GPL_KEY , .buildopt_sum = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .reload = reload, } [static]

Definition at line 255 of file codec_lpc10.c.

struct ast_module_info* ast_module_info = &__mod_info [static]

Definition at line 255 of file codec_lpc10.c.

struct ast_translator lintolpc10 [static]

Definition at line 207 of file codec_lpc10.c.

struct ast_translator lpc10tolin [static]

Definition at line 194 of file codec_lpc10.c.

Asterisk developer's documentation

codec_lpc10.c File Reference
Module: Codecs

Data Structures

Defines

Functions

Variables

Detailed Description

Define Documentation

Function Documentation

Variable Documentation

Asterisk developer's documentation

codec_lpc10.c File ReferenceModule: Codecs

Data Structures

Defines

Functions

Variables

Detailed Description

Define Documentation

Function Documentation

Variable Documentation

codec_lpc10.c File Reference
Module: Codecs