diff options
Diffstat (limited to 'formats/format_attr_silk.c')
| -rw-r--r-- | formats/format_attr_silk.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/formats/format_attr_silk.c b/formats/format_attr_silk.c new file mode 100644 index 000000000..49122fe80 --- /dev/null +++ b/formats/format_attr_silk.c @@ -0,0 +1,215 @@ +/* + * 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, +); |