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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 Put a jitterbuffer on the read side of a channel
*
* \author David Vossel <dvossel@digium.com>
*
* \ingroup functions
*/
/*** MODULEINFO
<support_level>core</support_level>
***/
#include "asterisk.h"
#include "asterisk/module.h"
#include "asterisk/channel.h"
#include "asterisk/framehook.h"
#include "asterisk/frame.h"
#include "asterisk/pbx.h"
#include "asterisk/abstract_jb.h"
#include "asterisk/timing.h"
#include "asterisk/app.h"
/*** DOCUMENTATION
<function name="JITTERBUFFER" language="en_US">
<synopsis>
Add a Jitterbuffer to the Read side of the channel. This dejitters the audio stream before it reaches the Asterisk core. This is a write only function.
</synopsis>
<syntax>
<parameter name="jitterbuffer type" required="true">
<optionlist>
<option name="fixed">
<para>Set a fixed jitterbuffer on the channel.</para>
</option>
<option name="adaptive">
<para>Set an adaptive jitterbuffer on the channel.</para>
</option>
<option name="disabled">
<para>Remove a previously set jitterbuffer from the channel.</para>
</option>
</optionlist>
</parameter>
</syntax>
<description>
<para>Jitterbuffers are constructed in two different ways.
The first always take three arguments: <replaceable>max_size</replaceable>,
<replaceable>resync_threshold</replaceable>, and <replaceable>target_extra</replaceable>.
Alternatively, a single argument of <literal>default</literal> can be provided,
which will construct the default jitterbuffer for the given
<replaceable>jitterbuffer type</replaceable>.</para>
<para>The arguments are:</para>
<para><replaceable>max_size</replaceable>: Length in milliseconds of the buffer.
Defaults to 200 ms.</para>
<para><replaceable>resync_threshold</replaceable>: The length in milliseconds over
which a timestamp difference will result in resyncing the jitterbuffer.
Defaults to 1000ms.</para>
<para>target_extra: This option only affects the adaptive jitterbuffer. It represents
the amount time in milliseconds by which the new jitter buffer will pad its size.
Defaults to 40ms.</para>
<example title="Fixed with defaults" language="text">
exten => 1,1,Set(JITTERBUFFER(fixed)=default)
</example>
<example title="Fixed with 200ms max size" language="text">
exten => 1,1,Set(JITTERBUFFER(fixed)=200)
</example>
<example title="Fixed with 200ms max size, resync threshold 1500" language="text">
exten => 1,1,Set(JITTERBUFFER(fixed)=200,1500)
</example>
<example title="Adaptive with defaults" language="text">
exten => 1,1,Set(JITTERBUFFER(adaptive)=default)
</example>
<example title="Adaptive with 200ms max size, 60ms target extra" language="text">
exten => 1,1,Set(JITTERBUFFER(adaptive)=200,,60)
</example>
<example title="Set a fixed jitterbuffer with defaults; then remove it" language="text">
exten => 1,1,Set(JITTERBUFFER(fixed)=default)
exten => 1,n,Set(JITTERBUFFER(disabled)=)
</example>
<note><para>If a channel specifies a jitterbuffer due to channel driver configuration and
the JITTERBUFFER function has set a jitterbuffer for that channel, the jitterbuffer set by
the JITTERBUFFER function will take priority and the jitterbuffer set by the channel
configuration will not be applied.</para></note>
</description>
</function>
***/
static int jb_helper(struct ast_channel *chan, const char *cmd, char *data, const char *value)
{
struct ast_jb_conf jb_conf;
if (!chan) {
ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
return -1;
}
/* Initialize and set jb_conf */
ast_jb_conf_default(&jb_conf);
/* Now check user options to see if any of the defaults need to change. */
if (!ast_strlen_zero(data)) {
if (strcasecmp(data, "fixed") &&
strcasecmp(data, "adaptive") &&
strcasecmp(data, "disabled")) {
ast_log(LOG_WARNING, "Unknown Jitterbuffer type %s. Failed to create jitterbuffer.\n", data);
return -1;
}
ast_copy_string(jb_conf.impl, data, sizeof(jb_conf.impl));
}
if (!ast_strlen_zero(value) && strcasecmp(value, "default")) {
char *parse = ast_strdupa(value);
int res = 0;
AST_DECLARE_APP_ARGS(args,
AST_APP_ARG(max_size);
AST_APP_ARG(resync_threshold);
AST_APP_ARG(target_extra);
);
AST_STANDARD_APP_ARGS(args, parse);
if (!ast_strlen_zero(args.max_size)) {
res |= ast_jb_read_conf(&jb_conf,
"jbmaxsize",
args.max_size);
}
if (!ast_strlen_zero(args.resync_threshold)) {
res |= ast_jb_read_conf(&jb_conf,
"jbresyncthreshold",
args.resync_threshold);
}
if (!ast_strlen_zero(args.target_extra)) {
res |= ast_jb_read_conf(&jb_conf,
"jbtargetextra",
args.target_extra);
}
if (res) {
ast_log(LOG_WARNING, "Invalid jitterbuffer parameters %s\n", value);
}
}
ast_jb_create_framehook(chan, &jb_conf, 0);
return 0;
}
static struct ast_custom_function jb_function = {
.name = "JITTERBUFFER",
.write = jb_helper,
};
static int unload_module(void)
{
return ast_custom_function_unregister(&jb_function);
}
static int load_module(void)
{
int res = ast_custom_function_register(&jb_function);
return res ? AST_MODULE_LOAD_DECLINE : AST_MODULE_LOAD_SUCCESS;
}
AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Jitter buffer for read side of channel.");
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