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<?xml version="1.0" encoding="ISO-8859-1"?>
<refentry id="stdin" xmlns="http://docbook.org/ns/docbook" version="5.0">
<!--
Header
-->
<refmeta>
<refentrytitle>glasscoder-ipc</refentrytitle>
<manvolnum>7</manvolnum>
<refmiscinfo class='source'>October 2019</refmiscinfo>
<refmiscinfo class='manual'>Linux Audio Manual</refmiscinfo>
</refmeta>
<refnamediv>
<refname>glasscoder-ipc</refname>
<refpurpose>IPC methods for the GlassCoder stream encoder</refpurpose>
</refnamediv>
<info>
<author>
<personname>
<firstname>Fred</firstname>
<surname>Gleason</surname>
<email>fredg@paravelsystems.com</email>
</personname>
<contrib>Application Author</contrib>
</author>
</info>
<!--
Body
-->
<refsynopsisdiv id='synopsis'>
<cmdsynopsis>
<command>glasscoder</command>
<arg choice='opt'><replaceable>OPTIONS</replaceable></arg>
<sbr/>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1 id='description'><title>Description</title>
<para>
<command>glasscoder</command><manvolnum>1</manvolnum> is an audio encoder
that is capable of generating live streams using a variety of formats and
sending them to an Icecast or Shoutcast audio streaming server or posting
them as HTTP Live Streams [HLS]. For more information regarding its
overall capabilities, see the
<command>glasscoder</command><manvolnum>1</manvolnum> man page.
</para>
<para>
A running <command>glasscoder</command><manvolnum>1</manvolnum>
instance can be monitored and controlled by means of two different IPC
methods: its standard input/output streams and HTTP calls.
</para>
</refsect1>
<refsect1 id='stdoout-control'><title>Monitoring via Standard Output</title>
<para>
<command>glasscoder</command><manvolnum>1</manvolnum> can output
realtime information about current operating state via its standard
output and/or error streams. The location and format in which this
information is generated is controlled by means of the
<option>--errors-to</option> and <option>--meter-data</option> options.
</para>
<para>
When <userinput>--errors-to=STDOUT</userinput> is specified,
<command>glasscoder</command><manvolnum>1</manvolnum> will output
error messages on standard output in the following machine-readable
format:
</para>
<para>
<synopsis>
ER <arg><replaceable>priority</replaceable></arg> <arg><replaceable>msg</replaceable></arg>
</synopsis>
</para>
<para>
where <arg><replaceable>priority</replaceable></arg> is an
integer the indicates the priority level of the error as defined by
the <command>syslog</command><manvolnum>3</manvolnum> interface and
<arg><replaceable>msg</replaceable></arg> is a text
string describing the error. Each message is terminated by a newline
character.
</para>
<para>
When <userinput>--meter-data</userinput> is specified,
<command>glasscoder</command><manvolnum>1</manvolnum> will output
realtime audio level information suitable for being rendered as an
audio meter display in the following format:
</para>
<para>
<synopsis>
ME <arg><replaceable>left-lvl</replaceable><replaceable>right-lvl</replaceable></arg>
</synopsis>
</para>
<para>
where each argument is the current audio level of the corresponding
channel in hexidecimal, referenced to 0 dBFS. Each message is terminated
by a newline character.
</para>
</refsect1>
<refsect1 id='stdin-control'><title>Control via Standard Input</title>
<para>
<command>glasscoder</command><manvolnum>1</manvolnum> supports the
following command, sent via standard input:
</para>
<para>
<synopsis>
MD <arg><replaceable>text</replaceable></arg>
</synopsis>
</para>
<para>
Send the metadata
<arg choice='opt'><replaceable>text</replaceable></arg> to the stream.
The command should be terminated by newline.
</para>
</refsect1>
<refsect1 id='http-control'><title>Control via HTTP</title>
<para>
If the <option>--metadata-port=<replaceable>port</replaceable></option>
option is given a non-zero value, metadata updates can be sent to the
stream by means of HTTP calls. For details, see the METADATA section of
the <command>glasscoder</command><manvolnum>1</manvolnum> man page.
</para>
</refsect1>
<refsect1 id='http-control'><title>Proxy Connections</title>
<para>
It is possible to implement proxy connectors for
<command>glasscoder</command><manvolnum>1</manvolnum>'s IceStreamer server
through use of the <option>--server-pipe</option> command switch. This
switch will create a UNIX socket which can be used to pipe in open
descriptors for player connections by means of ancilliary socket messages
with the <userinput>SCM_RIGHTS</userinput> message type. See the
<command>unix</command><manvolnum>7</manvolnum> man page for more
information. A fully worked-out example is also available in the
GlassCoder source package in the 'src/tests/' subdirectory.
</para>
</refsect1>
<refsect1 id='author'><title>Author</title>
<para>
Fred Gleason <fredg@paravelsystems.com>
</para>
</refsect1>
<refsect1 id='see_also'><title>See Also</title>
<para>
<citerefentry>
<refentrytitle>glasscoder</refentrytitle><manvolnum>1</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>cmsg</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>sendmsg</refentrytitle><manvolnum>2</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>unix</refentrytitle><manvolnum>7</manvolnum>
</citerefentry>
</para>
</refsect1>
</refentry>
|
