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/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2011, Digium, Inc.
*
* David Vossel <dvossel@digium.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
/*!
* \file
* \brief SILK format attribute interface
*
* \author David Vossel <dvossel@digium.com>
*/
#include "asterisk.h"
ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#include "asterisk/module.h"
#include "asterisk/format.h"
/*!
* \brief SILK attribute structure.
*
* \note The only attribute that affects compatibility here is the sample rate.
*/
struct silk_attr {
unsigned int samplerate;
unsigned int maxbitrate;
unsigned int dtx;
unsigned int fec;
unsigned int packetloss_percentage;
};
static enum ast_format_cmp_res silk_cmp(const struct ast_format_attr *fattr1, const struct ast_format_attr *fattr2)
{
struct silk_attr *attr1 = (struct silk_attr *) fattr1;
struct silk_attr *attr2 = (struct silk_attr *) fattr2;
if (attr1->samplerate == attr2->samplerate) {
return AST_FORMAT_CMP_EQUAL;
}
return AST_FORMAT_CMP_NOT_EQUAL;
}
static int silk_get_val(const struct ast_format_attr *fattr, int key, void *result)
{
const struct silk_attr *attr = (struct silk_attr *) fattr;
int *val = result;
switch (key) {
case SILK_ATTR_KEY_SAMP_RATE:
*val = attr->samplerate;
break;
case SILK_ATTR_KEY_MAX_BITRATE:
*val = attr->maxbitrate;
break;
case SILK_ATTR_KEY_DTX:
*val = attr->dtx;
break;
case SILK_ATTR_KEY_FEC:
*val = attr->fec;
break;
case SILK_ATTR_KEY_PACKETLOSS_PERCENTAGE:
*val = attr->packetloss_percentage;
break;
default:
return -1;
ast_log(LOG_WARNING, "unknown attribute type %d\n", key);
}
return 0;
}
static int silk_isset(const struct ast_format_attr *fattr, va_list ap)
{
enum silk_attr_keys key;
const struct silk_attr *attr = (struct silk_attr *) fattr;
for (key = va_arg(ap, int);
key != AST_FORMAT_ATTR_END;
key = va_arg(ap, int))
{
switch (key) {
case SILK_ATTR_KEY_SAMP_RATE:
if (attr->samplerate != (va_arg(ap, int))) {
return -1;
}
break;
case SILK_ATTR_KEY_MAX_BITRATE:
if (attr->maxbitrate != (va_arg(ap, int))) {
return -1;
}
break;
case SILK_ATTR_KEY_DTX:
if (attr->dtx != (va_arg(ap, int))) {
return -1;
}
break;
case SILK_ATTR_KEY_FEC:
if (attr->fec != (va_arg(ap, int))) {
return -1;
}
break;
case SILK_ATTR_KEY_PACKETLOSS_PERCENTAGE:
if (attr->packetloss_percentage != (va_arg(ap, int))) {
return -1;
}
break;
default:
return -1;
ast_log(LOG_WARNING, "unknown attribute type %d\n", key);
}
}
return 0;
}
static int silk_getjoint(const struct ast_format_attr *fattr1, const struct ast_format_attr *fattr2, struct ast_format_attr *result)
{
struct silk_attr *attr1 = (struct silk_attr *) fattr1;
struct silk_attr *attr2 = (struct silk_attr *) fattr2;
struct silk_attr *attr_res = (struct silk_attr *) result;
int joint = -1;
attr_res->samplerate = attr1->samplerate & attr2->samplerate;
/* sample rate is the only attribute that has any bearing on if joint capabilities exist or not */
if (attr_res->samplerate) {
joint = 0;
}
/* 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 joint;
}
static void silk_set(struct ast_format_attr *fattr, va_list ap)
{
enum silk_attr_keys key;
struct silk_attr *attr = (struct silk_attr *) fattr;
for (key = va_arg(ap, int);
key != AST_FORMAT_ATTR_END;
key = va_arg(ap, int))
{
switch (key) {
case SILK_ATTR_KEY_SAMP_RATE:
attr->samplerate = (va_arg(ap, int));
break;
case SILK_ATTR_KEY_MAX_BITRATE:
attr->maxbitrate = (va_arg(ap, int));
break;
case SILK_ATTR_KEY_DTX:
attr->dtx = (va_arg(ap, int));
break;
case SILK_ATTR_KEY_FEC:
attr->fec = (va_arg(ap, int));
break;
case SILK_ATTR_KEY_PACKETLOSS_PERCENTAGE:
attr->packetloss_percentage = (va_arg(ap, int));
break;
default:
ast_log(LOG_WARNING, "unknown attribute type %d\n", key);
}
}
}
static struct ast_format_attr_interface silk_interface = {
.id = AST_FORMAT_SILK,
.format_attr_cmp = silk_cmp,
.format_attr_get_joint = silk_getjoint,
.format_attr_set = silk_set,
.format_attr_isset = silk_isset,
.format_attr_get_val = silk_get_val,
};
static int load_module(void)
{
if (ast_format_attr_reg_interface(&silk_interface)) {
return AST_MODULE_LOAD_DECLINE;
}
return AST_MODULE_LOAD_SUCCESS;
}
static int unload_module(void)
{
ast_format_attr_unreg_interface(&silk_interface);
return 0;
}
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "SILK Format Attribute Module",
.load = load_module,
.unload = unload_module,
.load_pri = AST_MODPRI_CHANNEL_DEPEND,
);
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