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/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2015, Alexander Traud
*
* Alexander Traud <pabstraud@compuserve.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 VP8 format attribute interface
*
* \author Alexander Traud <pabstraud@compuserve.com>
*
* \note http://tools.ietf.org/html/draft-ietf-payload-vp8
*/
/*** MODULEINFO
<support_level>core</support_level>
***/
#include "asterisk.h"
#include "asterisk/module.h"
#include "asterisk/format.h"
#include "asterisk/logger.h" /* for ast_log, LOG_WARNING */
#include "asterisk/strings.h" /* for ast_str_append */
#include "asterisk/utils.h" /* for MIN, ast_malloc, ast_free */
struct vp8_attr {
unsigned int maximum_frame_rate;
unsigned int maximum_frame_size;
};
static struct vp8_attr default_vp8_attr = {
.maximum_frame_rate = UINT_MAX,
.maximum_frame_size = UINT_MAX,
};
static void vp8_destroy(struct ast_format *format)
{
struct vp8_attr *attr = ast_format_get_attribute_data(format);
ast_free(attr);
}
static int vp8_clone(const struct ast_format *src, struct ast_format *dst)
{
struct vp8_attr *original = ast_format_get_attribute_data(src);
struct vp8_attr *attr = ast_malloc(sizeof(*attr));
if (!attr) {
return -1;
}
if (original) {
*attr = *original;
} else {
*attr = default_vp8_attr;
}
ast_format_set_attribute_data(dst, attr);
return 0;
}
static struct ast_format *vp8_parse_sdp_fmtp(const struct ast_format *format, const char *attributes)
{
struct ast_format *cloned;
struct vp8_attr *attr;
const char *kvp;
unsigned int val;
cloned = ast_format_clone(format);
if (!cloned) {
return NULL;
}
attr = ast_format_get_attribute_data(cloned);
if ((kvp = strstr(attributes, "max-fr")) && sscanf(kvp, "max-fr=%30u", &val) == 1) {
attr->maximum_frame_rate = val;
} else {
attr->maximum_frame_rate = UINT_MAX;
}
if ((kvp = strstr(attributes, "max-fs")) && sscanf(kvp, "max-fs=%30u", &val) == 1) {
attr->maximum_frame_size = val;
} else {
attr->maximum_frame_size = UINT_MAX;
}
return cloned;
}
static void vp8_generate_sdp_fmtp(const struct ast_format *format, unsigned int payload, struct ast_str **str)
{
struct vp8_attr *attr = ast_format_get_attribute_data(format);
int added = 0;
if (!attr) {
/*
* (Only) cached formats do not have attribute data assigned because
* they were created before this attribute module was registered.
* Therefore, we assume the default attribute values here.
*/
attr = &default_vp8_attr;
}
if (UINT_MAX != attr->maximum_frame_rate) {
if (added) {
ast_str_append(str, 0, ";");
} else if (0 < ast_str_append(str, 0, "a=fmtp:%u ", payload)) {
added = 1;
}
ast_str_append(str, 0, "max-fr=%u", attr->maximum_frame_rate);
}
if (UINT_MAX != attr->maximum_frame_size) {
if (added) {
ast_str_append(str, 0, ";");
} else if (0 < ast_str_append(str, 0, "a=fmtp:%u ", payload)) {
added = 1;
}
ast_str_append(str, 0, "max-fs=%u", attr->maximum_frame_size);
}
if (added) {
ast_str_append(str, 0, "\r\n");
}
}
static struct ast_format *vp8_getjoint(const struct ast_format *format1, const struct ast_format *format2)
{
struct vp8_attr *attr1 = ast_format_get_attribute_data(format1);
struct vp8_attr *attr2 = ast_format_get_attribute_data(format2);
struct ast_format *jointformat;
struct vp8_attr *attr_res;
if (!attr1) {
attr1 = &default_vp8_attr;
}
if (!attr2) {
attr2 = &default_vp8_attr;
}
jointformat = ast_format_clone(format1);
if (!jointformat) {
return NULL;
}
attr_res = ast_format_get_attribute_data(jointformat);
attr_res->maximum_frame_rate = MIN(attr1->maximum_frame_rate, attr2->maximum_frame_rate);
attr_res->maximum_frame_size = MIN(attr1->maximum_frame_size, attr2->maximum_frame_size);
return jointformat;
}
static struct ast_format *vp8_set(const struct ast_format *format, const char *name, const char *value)
{
struct ast_format *cloned;
struct vp8_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, "maximum_frame_rate")) {
attr->maximum_frame_rate = val;
} else if (!strcasecmp(name, "maximum_frame_size")) {
attr->maximum_frame_size = val;
} else {
ast_log(LOG_WARNING, "unknown attribute type %s\n", name);
}
return cloned;
}
static struct ast_format_interface vp8_interface = {
.format_destroy = vp8_destroy,
.format_clone = vp8_clone,
.format_get_joint = vp8_getjoint,
.format_attribute_set = vp8_set,
.format_parse_sdp_fmtp = vp8_parse_sdp_fmtp,
.format_generate_sdp_fmtp = vp8_generate_sdp_fmtp,
};
static int load_module(void)
{
if (ast_format_interface_register("vp8", &vp8_interface)) {
return AST_MODULE_LOAD_DECLINE;
}
return AST_MODULE_LOAD_SUCCESS;
}
static int unload_module(void)
{
return 0;
}
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "VP8 Format Attribute Module",
.support_level = AST_MODULE_SUPPORT_CORE,
.load = load_module,
.unload = unload_module,
.load_pri = AST_MODPRI_CHANNEL_DEPEND,
);
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