Sun May 20 06:37:03 2012

Asterisk developer's documentation

res_format_attr_silk.c File Reference

SILK format attribute interface. More...

#include "asterisk.h"
#include "asterisk/module.h"
#include "asterisk/format.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)
static int load_module (void)
static enum ast_format_cmp_res silk_cmp (const struct ast_format_attr *fattr1, const struct ast_format_attr *fattr2)
static int silk_get_val (const struct ast_format_attr *fattr, int key, void *result)
static int silk_getjoint (const struct ast_format_attr *fattr1, const struct ast_format_attr *fattr2, struct ast_format_attr *result)
static int silk_isset (const struct ast_format_attr *fattr, va_list ap)
static void silk_set (struct ast_format_attr *fattr, va_list ap)
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 = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .load_pri = AST_MODPRI_CHANNEL_DEPEND, }
static struct ast_module_info * ast_module_info = &__mod_info
static struct
ast_format_attr_interface 		silk_interface

Detailed Description

SILK format attribute interface.

Author:
David Vossel <dvossel@digium.com>

Definition in file res_format_attr_silk.c.

Function Documentation

static void __reg_module ( void   )  [static]

Definition at line 219 of file res_format_attr_silk.c.

static void __unreg_module ( void   )  [static]

Definition at line 219 of file res_format_attr_silk.c.

static int load_module ( void   )  [static]

Definition at line 200 of file res_format_attr_silk.c.

References ast_format_attr_reg_interface(), AST_MODULE_LOAD_DECLINE, and AST_MODULE_LOAD_SUCCESS.

00201 {
00202    if (ast_format_attr_reg_interface(&silk_interface)) {
00203       return AST_MODULE_LOAD_DECLINE;
00204    }
00205 
00206    return AST_MODULE_LOAD_SUCCESS;
00207 }

static enum ast_format_cmp_res silk_cmp ( const struct ast_format_attr *  fattr1,
const struct ast_format_attr *  fattr2 
) [static]

Definition at line 50 of file res_format_attr_silk.c.

References AST_FORMAT_CMP_EQUAL, AST_FORMAT_CMP_NOT_EQUAL, and silk_attr::samplerate.

00051 {
00052    struct silk_attr *attr1 = (struct silk_attr *) fattr1;
00053    struct silk_attr *attr2 = (struct silk_attr *) fattr2;
00054 
00055    if (attr1->samplerate == attr2->samplerate) {
00056       return AST_FORMAT_CMP_EQUAL;
00057    }
00058    return AST_FORMAT_CMP_NOT_EQUAL;
00059 }

static int silk_get_val ( const struct ast_format_attr *  fattr,
int  key,
void *  result 
) [static]

Definition at line 61 of file res_format_attr_silk.c.

References ast_log(), silk_attr::dtx, silk_attr::fec, LOG_WARNING, silk_attr::maxbitrate, silk_attr::packetloss_percentage, silk_attr::samplerate, SILK_ATTR_KEY_DTX, SILK_ATTR_KEY_FEC, SILK_ATTR_KEY_MAX_BITRATE, SILK_ATTR_KEY_PACKETLOSS_PERCENTAGE, and SILK_ATTR_KEY_SAMP_RATE.

00062 {
00063    const struct silk_attr *attr = (struct silk_attr *) fattr;
00064    int *val = result;
00065 
00066    switch (key) {
00067    case SILK_ATTR_KEY_SAMP_RATE:
00068       *val = attr->samplerate;
00069       break;
00070    case SILK_ATTR_KEY_MAX_BITRATE:
00071       *val = attr->maxbitrate;
00072       break;
00073    case SILK_ATTR_KEY_DTX:
00074       *val = attr->dtx;
00075       break;
00076    case SILK_ATTR_KEY_FEC:
00077       *val = attr->fec;
00078       break;
00079    case SILK_ATTR_KEY_PACKETLOSS_PERCENTAGE:
00080       *val = attr->packetloss_percentage;
00081       break;
00082    default:
00083       ast_log(LOG_WARNING, "unknown attribute type %d\n", key);
00084       return -1;
00085    }
00086    return 0;
00087 }

static int silk_getjoint ( const struct ast_format_attr *  fattr1,
const struct ast_format_attr *  fattr2,
struct ast_format_attr *  result 
) [static]

Definition at line 131 of file res_format_attr_silk.c.

References silk_attr::dtx, silk_attr::fec, MAX, silk_attr::maxbitrate, MIN, silk_attr::packetloss_percentage, and silk_attr::samplerate.

00132 {
00133    struct silk_attr *attr1 = (struct silk_attr *) fattr1;
00134    struct silk_attr *attr2 = (struct silk_attr *) fattr2;
00135    struct silk_attr *attr_res = (struct silk_attr *) result;
00136    int joint = -1;
00137 
00138    attr_res->samplerate = attr1->samplerate & attr2->samplerate;
00139    /* sample rate is the only attribute that has any bearing on if joint capabilities exist or not */
00140    if (attr_res->samplerate) {
00141       joint = 0;
00142    }
00143    /* Take the lowest max bitrate */
00144    attr_res->maxbitrate = MIN(attr1->maxbitrate, attr2->maxbitrate);
00145 
00146    /* Only do dtx if both sides want it. DTX is a trade off between
00147     * computational complexity and bandwidth. */
00148    attr_res->dtx = attr1->dtx && attr2->dtx ? 1 : 0;
00149 
00150    /* Only do FEC if both sides want it.  If a peer specifically requests not
00151     * to receive with FEC, it may be a waste of bandwidth. */
00152    attr_res->fec = attr1->fec && attr2->fec ? 1 : 0;
00153 
00154    /* Use the maximum packetloss percentage between the two attributes. This affects how
00155     * much redundancy is used in the FEC. */
00156    attr_res->packetloss_percentage = MAX(attr1->packetloss_percentage, attr2->packetloss_percentage);
00157    return joint;
00158 }

static int silk_isset ( const struct ast_format_attr *  fattr,
va_list  ap 
) [static]

Definition at line 89 of file res_format_attr_silk.c.

References AST_FORMAT_ATTR_END, ast_log(), silk_attr::dtx, silk_attr::fec, LOG_WARNING, silk_attr::maxbitrate, silk_attr::packetloss_percentage, silk_attr::samplerate, SILK_ATTR_KEY_DTX, SILK_ATTR_KEY_FEC, SILK_ATTR_KEY_MAX_BITRATE, SILK_ATTR_KEY_PACKETLOSS_PERCENTAGE, and SILK_ATTR_KEY_SAMP_RATE.

00090 {
00091    enum silk_attr_keys key;
00092    const struct silk_attr *attr = (struct silk_attr *) fattr;
00093 
00094    for (key = va_arg(ap, int);
00095       key != AST_FORMAT_ATTR_END;
00096       key = va_arg(ap, int))
00097    {
00098       switch (key) {
00099       case SILK_ATTR_KEY_SAMP_RATE:
00100          if (attr->samplerate != (va_arg(ap, int))) {
00101             return -1;
00102          }
00103          break;
00104       case SILK_ATTR_KEY_MAX_BITRATE:
00105          if (attr->maxbitrate != (va_arg(ap, int))) {
00106             return -1;
00107          }
00108          break;
00109       case SILK_ATTR_KEY_DTX:
00110          if (attr->dtx != (va_arg(ap, int))) {
00111             return -1;
00112          }
00113          break;
00114       case SILK_ATTR_KEY_FEC:
00115          if (attr->fec != (va_arg(ap, int))) {
00116             return -1;
00117          }
00118          break;
00119       case SILK_ATTR_KEY_PACKETLOSS_PERCENTAGE:
00120          if (attr->packetloss_percentage != (va_arg(ap, int))) {
00121             return -1;
00122          }
00123          break;
00124       default:
00125          ast_log(LOG_WARNING, "unknown attribute type %d\n", key);
00126          return -1;
00127       }
00128    }
00129    return 0;
00130 }

static void silk_set ( struct ast_format_attr *  fattr,
va_list  ap 
) [static]

Definition at line 160 of file res_format_attr_silk.c.

References AST_FORMAT_ATTR_END, ast_log(), silk_attr::dtx, silk_attr::fec, LOG_WARNING, silk_attr::maxbitrate, silk_attr::packetloss_percentage, silk_attr::samplerate, SILK_ATTR_KEY_DTX, SILK_ATTR_KEY_FEC, SILK_ATTR_KEY_MAX_BITRATE, SILK_ATTR_KEY_PACKETLOSS_PERCENTAGE, and SILK_ATTR_KEY_SAMP_RATE.

00161 {
00162    enum silk_attr_keys key;
00163    struct silk_attr *attr = (struct silk_attr *) fattr;
00164 
00165    for (key = va_arg(ap, int);
00166       key != AST_FORMAT_ATTR_END;
00167       key = va_arg(ap, int))
00168    {
00169       switch (key) {
00170       case SILK_ATTR_KEY_SAMP_RATE:
00171          attr->samplerate = (va_arg(ap, int));
00172          break;
00173       case SILK_ATTR_KEY_MAX_BITRATE:
00174          attr->maxbitrate = (va_arg(ap, int));
00175          break;
00176       case SILK_ATTR_KEY_DTX:
00177          attr->dtx = (va_arg(ap, int));
00178          break;
00179       case SILK_ATTR_KEY_FEC:
00180          attr->fec = (va_arg(ap, int));
00181          break;
00182       case SILK_ATTR_KEY_PACKETLOSS_PERCENTAGE:
00183          attr->packetloss_percentage = (va_arg(ap, int));
00184          break;
00185       default:
00186          ast_log(LOG_WARNING, "unknown attribute type %d\n", key);
00187       }
00188    }
00189 }

static int unload_module ( void   )  [static]

Definition at line 209 of file res_format_attr_silk.c.

References ast_format_attr_unreg_interface().

00210 {
00211    ast_format_attr_unreg_interface(&silk_interface);
00212    return 0;
00213 }

Variable Documentation

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 = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .load_pri = AST_MODPRI_CHANNEL_DEPEND, } [static]

Definition at line 219 of file res_format_attr_silk.c.

struct ast_module_info* ast_module_info = &__mod_info [static]

Definition at line 219 of file res_format_attr_silk.c.

struct ast_format_attr_interface silk_interface [static]

Definition at line 191 of file res_format_attr_silk.c.

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