res_format_attr_silk.c File Reference

SILK format attribute interface. More...

#include "asterisk.h"
#include <ctype.h>
#include "asterisk/module.h"
#include "asterisk/format.h"
#include "asterisk/logger.h"
#include "asterisk/strings.h"
#include "asterisk/utils.h"

Include dependency graph for res_format_attr_silk.c:

Go to the source code of this file.

Data Structures
struct	silk_attr
	SILK attribute structure. More...

Functions
static void	__reg_module (void)
static void	__unreg_module (void)
struct ast_module *	AST_MODULE_SELF_SYM (void)
static void	attr_init (struct silk_attr *attr)
static int	load_module (void)
static int	silk_clone (const struct ast_format *src, struct ast_format *dst)
static enum ast_format_cmp_res	silk_cmp (const struct ast_format *format1, const struct ast_format *format2)
static void	silk_destroy (struct ast_format *format)
static void	silk_generate_sdp_fmtp (const struct ast_format *format, unsigned int payload, struct ast_str **str)
static const void *	silk_get (const struct ast_format *format, const char *name)
static struct ast_format *	silk_getjoint (const struct ast_format *format1, const struct ast_format *format2)
static struct ast_format *	silk_parse_sdp_fmtp (const struct ast_format *format, const char *attributes)
static struct ast_format *	silk_set (const struct ast_format *format, const char *name, const char *value)
static int	unload_module (void)

Variables
static struct ast_module_info	__mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_ORDER , .description = "SILK Format Attribute Module" , .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 = "30ef0c93b36035ec78c9cfd712d36d9b" , .support_level = AST_MODULE_SUPPORT_CORE, .load = load_module, .unload = unload_module, .load_pri = AST_MODPRI_CHANNEL_DEPEND, }
static const struct ast_module_info *	ast_module_info = &__mod_info
static struct ast_format_interface	silk_interface

Detailed Description

SILK format attribute interface.

Author

David Vossel dvoss.nosp@m.el@d.nosp@m.igium.nosp@m..com

Definition in file res_format_attr_silk.c.

Function Documentation

__reg_module()

static void __reg_module ( void  )

static

Definition at line 267 of file res_format_attr_silk.c.

__unreg_module()

static void __unreg_module ( void  )

static

Definition at line 267 of file res_format_attr_silk.c.

AST_MODULE_SELF_SYM()

struct ast_module* AST_MODULE_SELF_SYM

(

void

)

Definition at line 267 of file res_format_attr_silk.c.

attr_init()

static void attr_init ( struct silk_attr *  attr )

static

Definition at line 59 of file res_format_attr_silk.c.

Referenced by silk_clone(), and silk_getjoint().

{
   memset(attr, 0, sizeof(*attr));
}

load_module()

static int load_module ( void  )

static

Definition at line 248 of file res_format_attr_silk.c.

References ast_format_interface_register, AST_MODULE_LOAD_DECLINE, and AST_MODULE_LOAD_SUCCESS.

Referenced by unload_module().

{
   if (ast_format_interface_register("silk", &silk_interface)) {
      return AST_MODULE_LOAD_DECLINE;
   }

   return AST_MODULE_LOAD_SUCCESS;
}

silk_clone()

static int silk_clone ( const struct ast_format *  src, struct ast_format *  dst  )

static

Definition at line 64 of file res_format_attr_silk.c.

References ast_format_get_attribute_data(), ast_format_set_attribute_data(), ast_malloc, and attr_init().

{
   struct silk_attr *original = ast_format_get_attribute_data(src);
   struct silk_attr *attr = ast_malloc(sizeof(*attr));

   if (!attr) {
      return -1;
   }

   if (original) {
      *attr = *original;
   } else {
      attr_init(attr);
   }

   ast_format_set_attribute_data(dst, attr);

   return 0;
}

silk_cmp()

static enum ast_format_cmp_res silk_cmp ( const struct ast_format *  format1, const struct ast_format *  format2  )

static

Definition at line 135 of file res_format_attr_silk.c.

References AST_FORMAT_CMP_EQUAL, AST_FORMAT_CMP_NOT_EQUAL, and ast_format_get_sample_rate().

{
   if (ast_format_get_sample_rate(format1) == ast_format_get_sample_rate(format2)) {
      return AST_FORMAT_CMP_EQUAL;
   }

   return AST_FORMAT_CMP_NOT_EQUAL;
}

silk_destroy()

static void silk_destroy ( struct ast_format *  format )

static

Definition at line 52 of file res_format_attr_silk.c.

References ast_format_get_attribute_data(), and ast_free.

{
   struct silk_attr *attr = ast_format_get_attribute_data(format);

   ast_free(attr);
}

silk_generate_sdp_fmtp()

static void silk_generate_sdp_fmtp ( const struct ast_format *  format, unsigned int  payload, struct ast_str **  str  )

static

Definition at line 115 of file res_format_attr_silk.c.

References ast_format_get_attribute_data(), ast_str_append(), silk_attr::dtx, silk_attr::fec, and silk_attr::maxbitrate.

{
   struct silk_attr *attr = ast_format_get_attribute_data(format);

   if (!attr) {
      return;
   }

   if ((attr->maxbitrate > 5000) && (attr->maxbitrate < 40000)) {
      ast_str_append(str, 0, "a=fmtp:%u maxaveragebitrate=%u\r\n", payload, attr->maxbitrate);
   }

   if (attr->dtx) {
      ast_str_append(str, 0, "a=fmtp:%u usedtx=%u\r\n", payload, attr->dtx);
   }
   if (attr->fec) {
      ast_str_append(str, 0, "a=fmtp:%u useinbandfec=%u\r\n", payload, attr->fec);
   }
}

silk_get()

static const void* silk_get ( const struct ast_format *  format, const char *  name  )

static

Definition at line 216 of file res_format_attr_silk.c.

References ast_format_get_attribute_data(), ast_log, silk_attr::dtx, silk_attr::fec, LOG_WARNING, silk_attr::maxbitrate, NULL, and silk_attr::packetloss_percentage.

{
   struct silk_attr *attr = ast_format_get_attribute_data(format);
   unsigned int *val;

   if (!strcasecmp(name, "max_bitrate")) {
      val = &attr->maxbitrate;
   } else if (!strcasecmp(name, "dtx")) {
      val = &attr->dtx;
   } else if (!strcasecmp(name, "fec")) {
      val = &attr->fec;
   } else if (!strcasecmp(name, "packetloss_percentage")) {
      val = &attr->packetloss_percentage;
   } else {
      ast_log(LOG_WARNING, "unknown attribute type %s\n", name);
      return NULL;
   }

   return val;
}

silk_getjoint()

static struct ast_format* silk_getjoint ( const struct ast_format *  format1, const struct ast_format *  format2  )

static

Definition at line 144 of file res_format_attr_silk.c.

References ast_format_clone(), ast_format_get_attribute_data(), ast_format_get_sample_rate(), attr_init(), silk_attr::dtx, silk_attr::fec, MAX, silk_attr::maxbitrate, MIN, NULL, and silk_attr::packetloss_percentage.

{
   struct silk_attr *attr1 = ast_format_get_attribute_data(format1);
   struct silk_attr *attr2 = ast_format_get_attribute_data(format2);
   struct ast_format *jointformat;
   struct silk_attr *attr_res;

   if (ast_format_get_sample_rate(format1) != ast_format_get_sample_rate(format2)) {
      return NULL;
   }

   jointformat = ast_format_clone(format1);
   if (!jointformat) {
      return NULL;
   }
   attr_res = ast_format_get_attribute_data(jointformat);

   if (!attr1 || !attr2) {
      attr_init(attr_res);
   } else {
      /* Take the lowest max bitrate */
      attr_res->maxbitrate = MIN(attr1->maxbitrate, attr2->maxbitrate);

      /* Only do dtx if both sides want it. DTX is a trade off between
       * computational complexity and bandwidth. */
      attr_res->dtx = attr1->dtx && attr2->dtx ? 1 : 0;

      /* Only do FEC if both sides want it.  If a peer specifically requests not
       * to receive with FEC, it may be a waste of bandwidth. */
      attr_res->fec = attr1->fec && attr2->fec ? 1 : 0;

      /* Use the maximum packetloss percentage between the two attributes. This affects how
       * much redundancy is used in the FEC. */
      attr_res->packetloss_percentage = MAX(attr1->packetloss_percentage, attr2->packetloss_percentage);
   }

   return jointformat;
}

silk_parse_sdp_fmtp()

static struct ast_format* silk_parse_sdp_fmtp ( const struct ast_format *  format, const char *  attributes  )

static

Definition at line 84 of file res_format_attr_silk.c.

References ast_format_clone(), ast_format_get_attribute_data(), ast_strdupa, silk_attr::dtx, silk_attr::fec, silk_attr::maxbitrate, and NULL.

{
   char *attribs = ast_strdupa(attributes), *attrib;
   struct ast_format *cloned;
   struct silk_attr *attr;
   unsigned int val;

   cloned = ast_format_clone(format);
   if (!cloned) {
      return NULL;
   }
   attr = ast_format_get_attribute_data(cloned);

   /* lower-case everything, so we are case-insensitive */
   for (attrib = attribs; *attrib; ++attrib) {
      *attrib = tolower(*attrib);
   } /* based on channels/chan_sip.c:process_a_sdp_image() */

   if (sscanf(attribs, "maxaveragebitrate=%30u", &val) == 1) {
      attr->maxbitrate = val;
   }
   if (sscanf(attribs, "usedtx=%30u", &val) == 1) {
      attr->dtx = val;
   }
   if (sscanf(attribs, "useinbandfec=%30u", &val) == 1) {
      attr->fec = val;
   }

   return cloned;
}

silk_set()

static struct ast_format* silk_set ( const struct ast_format *  format, const char *  name, const char *  value  )

static

Definition at line 183 of file res_format_attr_silk.c.

References ast_format_clone(), ast_format_get_attribute_data(), ast_log, silk_attr::dtx, silk_attr::fec, LOG_WARNING, silk_attr::maxbitrate, NULL, and silk_attr::packetloss_percentage.

{
   struct ast_format *cloned;
   struct silk_attr *attr;
   unsigned int val;

   if (sscanf(value, "%30u", &val) != 1) {
      ast_log(LOG_WARNING, "Unknown value '%s' for attribute type '%s'\n",
         value, name);
      return NULL;
   }

   cloned = ast_format_clone(format);
   if (!cloned) {
      return NULL;
   }
   attr = ast_format_get_attribute_data(cloned);

   if (!strcasecmp(name, "max_bitrate")) {
      attr->maxbitrate = val;
   } else if (!strcasecmp(name, "dtx")) {
      attr->dtx = val;
   } else if (!strcasecmp(name, "fec")) {
      attr->fec = val;
   } else if (!strcasecmp(name, "packetloss_percentage")) {
      attr->packetloss_percentage = val;
   } else {
      ast_log(LOG_WARNING, "unknown attribute type %s\n", name);
   }

   return cloned;
}

unload_module()

static int unload_module ( void  )

static

Definition at line 257 of file res_format_attr_silk.c.

References AST_MODFLAG_LOAD_ORDER, AST_MODPRI_CHANNEL_DEPEND, AST_MODULE_INFO(), AST_MODULE_SUPPORT_CORE, ASTERISK_GPL_KEY, and load_module().

{
   return 0;
}

Variable Documentation

__mod_info

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_ORDER , .description = "SILK Format Attribute Module" , .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 = "30ef0c93b36035ec78c9cfd712d36d9b" , .support_level = AST_MODULE_SUPPORT_CORE, .load = load_module, .unload = unload_module, .load_pri = AST_MODPRI_CHANNEL_DEPEND, }

static

Definition at line 267 of file res_format_attr_silk.c.

ast_module_info

const struct ast_module_info* ast_module_info = &__mod_info

static

Definition at line 267 of file res_format_attr_silk.c.

silk_interface

struct ast_format_interface silk_interface

static

Definition at line 237 of file res_format_attr_silk.c.