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<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<table summary="layout" width="66%" border="0" cellpadding="0" cellspacing="0"><tr><td><table summary="layout" width="100%" border="0" cellpadding="2" cellspacing="1">
<tr><td class="header">LinuxSampler Developers</td><td class="header">C. Schoenebeck</td></tr>
<tr><td class="header">Internet-Draft</td><td class="header">Interessengemeinschaft Software</td></tr>
<tr><td class="header">Expires: May 29, 2007</td><td class="header">Engineering e. V.</td></tr>
<tr><td class="header">&nbsp;</td><td class="header">November 25, 2006</td></tr>
</table></td></tr></table>
<div align="right"><span class="title"><br />LinuxSampler Control Protocol</span></div>
<div align="right"><span class="title"><br />LSCP 1.1</span></div>

<h3>Status of this Memo</h3>
<p>
This document is an Internet-Draft and is
in full conformance with all provisions of Section&nbsp;10 of RFC&nbsp;2026.</p>
<p>
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups.
Note that other groups may also distribute working documents as
Internet-Drafts.</p>
<p>
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any time.
It is inappropriate to use Internet-Drafts as reference material or to cite
them other than as &ldquo;work in progress.&rdquo;</p>
<p>
The list of current Internet-Drafts can be accessed at
<a href='http://www.ietf.org/ietf/1id-abstracts.txt'>http://www.ietf.org/ietf/1id-abstracts.txt</a>.</p>
<p>
The list of Internet-Draft Shadow Directories can be accessed at
<a href='http://www.ietf.org/shadow.html'>http://www.ietf.org/shadow.html</a>.</p>
<p>
This Internet-Draft will expire on May 29, 2007.</p>

<h3>Copyright Notice</h3>
<p>
Copyright &copy; The Internet Society (2006). All Rights Reserved.</p>

<h3>Abstract</h3>

<p>The LinuxSampler Control Protocol (LSCP) is an
            application-level protocol primarily intended for local and
            remote controlling the LinuxSampler backend application, which is a
            sophisticated server-like console application essentially playing
            back audio samples and manipulating the samples in real time to
            certain extent.
</p><a name="toc"></a><br /><hr />
<h3>Table of Contents</h3>
<p class="toc">
<a href="#anchor1">1.</a>&nbsp;
Requirements notation<br />
<a href="#LSCP versioning">2.</a>&nbsp;
Versioning of this specification<br />
<a href="#anchor2">3.</a>&nbsp;
Introduction<br />
<a href="#anchor3">4.</a>&nbsp;
Focus of this protocol<br />
<a href="#anchor4">5.</a>&nbsp;
Communication Overview<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#anchor5">5.1.</a>&nbsp;
Request/response communication method<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#anchor6">5.1.1.</a>&nbsp;
Result format<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#anchor7">5.2.</a>&nbsp;
Subscribe/notify communication method<br />
<a href="#control_commands">6.</a>&nbsp;
Description for control commands<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#anchor8">6.1.</a>&nbsp;
Ignored lines and comments<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#anchor9">6.2.</a>&nbsp;
Configuring audio drivers<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET AVAILABLE_AUDIO_OUTPUT_DRIVERS">6.2.1.</a>&nbsp;
Getting amount of available audio output drivers<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#LIST AVAILABLE_AUDIO_OUTPUT_DRIVERS">6.2.2.</a>&nbsp;
Getting all available audio output drivers<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET AUDIO_OUTPUT_DRIVER INFO">6.2.3.</a>&nbsp;
Getting information about a specific audio
                output driver<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET AUDIO_OUTPUT_DRIVER_PARAMETER INFO">6.2.4.</a>&nbsp;
Getting information about specific audio
                output driver parameter<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#CREATE AUDIO_OUTPUT_DEVICE">6.2.5.</a>&nbsp;
Creating an audio output device<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#DESTROY AUDIO_OUTPUT_DEVICE">6.2.6.</a>&nbsp;
Destroying an audio output device<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET AUDIO_OUTPUT_DEVICES">6.2.7.</a>&nbsp;
Getting all created audio output device count<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#LIST AUDIO_OUTPUT_DEVICES">6.2.8.</a>&nbsp;
Getting all created audio output device list<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET AUDIO_OUTPUT_DEVICE INFO">6.2.9.</a>&nbsp;
Getting current settings of an audio output device<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET AUDIO_OUTPUT_DEVICE_PARAMETER">6.2.10.</a>&nbsp;
Changing settings of audio output devices<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET AUDIO_OUTPUT_CHANNEL INFO">6.2.11.</a>&nbsp;
Getting information about an audio channel<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET AUDIO_OUTPUT_CHANNEL_PARAMETER INFO">6.2.12.</a>&nbsp;
Getting information about specific audio channel parameter<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET AUDIO_OUTPUT_CHANNEL_PARAMETER">6.2.13.</a>&nbsp;
Changing settings of audio output channels<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#anchor10">6.3.</a>&nbsp;
Configuring MIDI input drivers<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET AVAILABLE_MIDI_INPUT_DRIVERS">6.3.1.</a>&nbsp;
Getting amount of available MIDI input drivers<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#LIST AVAILABLE_MIDI_INPUT_DRIVERS">6.3.2.</a>&nbsp;
Getting all available MIDI input drivers<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET MIDI_INPUT_DRIVER INFO">6.3.3.</a>&nbsp;
Getting information about a specific MIDI input driver<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET MIDI_INPUT_DRIVER_PARAMETER INFO">6.3.4.</a>&nbsp;
Getting information about specific MIDI input driver parameter<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#CREATE MIDI_INPUT_DEVICE">6.3.5.</a>&nbsp;
Creating a MIDI input device<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#DESTROY MIDI_INPUT_DEVICE">6.3.6.</a>&nbsp;
Destroying a MIDI input device<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET MIDI_INPUT_DEVICES">6.3.7.</a>&nbsp;
Getting all created MIDI input device count<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#LIST MIDI_INPUT_DEVICES">6.3.8.</a>&nbsp;
Getting all created MIDI input device list<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET MIDI_INPUT_DEVICE INFO">6.3.9.</a>&nbsp;
Getting current settings of a MIDI input device<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET MIDI_INPUT_DEVICE_PARAMETER">6.3.10.</a>&nbsp;
Changing settings of MIDI input devices<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET MIDI_INPUT_PORT INFO">6.3.11.</a>&nbsp;
Getting information about a MIDI port<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET MIDI_INPUT_PORT_PARAMETER INFO">6.3.12.</a>&nbsp;
Getting information about specific MIDI port parameter<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET MIDI_INPUT_PORT_PARAMETER">6.3.13.</a>&nbsp;
Changing settings of MIDI input ports<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#anchor11">6.4.</a>&nbsp;
Configuring sampler channels<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#LOAD INSTRUMENT">6.4.1.</a>&nbsp;
Loading an instrument<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#LOAD ENGINE">6.4.2.</a>&nbsp;
Loading a sampler engine<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET CHANNELS">6.4.3.</a>&nbsp;
Getting all created sampler channel count<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#LIST CHANNELS">6.4.4.</a>&nbsp;
Getting all created sampler channel list<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#ADD CHANNEL">6.4.5.</a>&nbsp;
Adding a new sampler channel<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#REMOVE CHANNEL">6.4.6.</a>&nbsp;
Removing a sampler channel<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET AVAILABLE_ENGINES">6.4.7.</a>&nbsp;
Getting amount of available engines<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#LIST AVAILABLE_ENGINES">6.4.8.</a>&nbsp;
Getting all available engines<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET ENGINE INFO">6.4.9.</a>&nbsp;
Getting information about an engine<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET CHANNEL INFO">6.4.10.</a>&nbsp;
Getting sampler channel information<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET CHANNEL VOICE_COUNT">6.4.11.</a>&nbsp;
Current number of active voices<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET CHANNEL STREAM_COUNT">6.4.12.</a>&nbsp;
Current number of active disk streams<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET CHANNEL BUFFER_FILL">6.4.13.</a>&nbsp;
Current fill state of disk stream buffers<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET CHANNEL AUDIO_OUTPUT_DEVICE">6.4.14.</a>&nbsp;
Setting audio output device<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET CHANNEL AUDIO_OUTPUT_TYP">6.4.15.</a>&nbsp;
Setting audio output type<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET CHANNEL AUDIO_OUTPUT_CHANNEL">6.4.16.</a>&nbsp;
Setting audio output channel<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET CHANNEL MIDI_INPUT_DEVICE">6.4.17.</a>&nbsp;
Setting MIDI input device<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET CHANNEL MIDI_INPUT_TYPE">6.4.18.</a>&nbsp;
Setting MIDI input type<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET CHANNEL MIDI_INPUT_PORT">6.4.19.</a>&nbsp;
Setting MIDI input port<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET CHANNEL MIDI_INPUT_CHANNEL">6.4.20.</a>&nbsp;
Setting MIDI input channel<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET CHANNEL VOLUME">6.4.21.</a>&nbsp;
Setting channel volume<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET CHANNEL MUTE">6.4.22.</a>&nbsp;
Muting a sampler channel<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET CHANNEL SOLO">6.4.23.</a>&nbsp;
Soloing a sampler channel<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#RESET CHANNEL">6.4.24.</a>&nbsp;
Resetting a sampler channel<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#anchor12">6.5.</a>&nbsp;
Controlling connection<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SUBSCRIBE">6.5.1.</a>&nbsp;
Register front-end for receiving event messages<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#UNSUBSCRIBE">6.5.2.</a>&nbsp;
Unregister front-end for not receiving event messages<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SET ECHO">6.5.3.</a>&nbsp;
Enable or disable echo of commands<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#QUIT">6.5.4.</a>&nbsp;
Close client connection<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#anchor13">6.6.</a>&nbsp;
Global commands<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET TOTAL_VOICE_COUNT">6.6.1.</a>&nbsp;
Current number of active voices<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET TOTAL_VOICE_COUNT_MAX">6.6.2.</a>&nbsp;
Maximum amount of active voices<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#RESET">6.6.3.</a>&nbsp;
Reset sampler<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#GET SERVER INFO">6.6.4.</a>&nbsp;
General sampler informations<br />
<a href="#command_syntax">7.</a>&nbsp;
Command Syntax<br />
<a href="#events">8.</a>&nbsp;
Events<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SUBSCRIBE CHANNEL">8.1.</a>&nbsp;
Number of sampler channels changed<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SUBSCRIBE VOICE_COUNT">8.2.</a>&nbsp;
Number of active voices changed<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SUBSCRIBE STREAM_COUNT">8.3.</a>&nbsp;
Number of active disk streams changed<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SUBSCRIBE BUFFER_FILL">8.4.</a>&nbsp;
Disk stream buffer fill state changed<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SUBSCRIBE INFO">8.5.</a>&nbsp;
Channel information changed<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SUBSCRIBE TOTAL_VOICE_COUNT">8.6.</a>&nbsp;
Total number of active voices changed<br />
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SUBSCRIBE MISCELLANEOUS">8.7.</a>&nbsp;
Miscellaneous and debugging events<br />
<a href="#anchor14">9.</a>&nbsp;
Security Considerations<br />
<a href="#anchor15">10.</a>&nbsp;
Acknowledgments<br />
<a href="#rfc.references1">11.</a>&nbsp;
References<br />
<a href="#rfc.authors">&#167;</a>&nbsp;
Author's Address<br />
<a href="#rfc.copyright">&#167;</a>&nbsp;
Intellectual Property and Copyright Statements<br />
</p>
<br clear="all" />

<a name="anchor1"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.1"></a><h3>1.&nbsp;Requirements notation</h3>

<p>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL",
            "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
            and "OPTIONAL" in this document are to be interpreted as
            described in <a class="info" href="#RFC2119">[RFC2119]<span> (</span><span class="info">Bradner, S., &ldquo;Key words for use in RFCs to Indicate Requirement Levels,&rdquo; 1997.</span><span>)</span></a>.
</p>
<p>This protocol is always case-sensitive if not explicitly
            claimed the opposite.
</p>
<p>In examples, "C:" and "S:" indicate lines sent by the client
            (front-end) and server (LinuxSampler) respectively. Lines in
            examples must be interpreted as every line being CRLF
            terminated (carriage return character followed by line feed
            character as defined in the ASCII standard), thus the following
            example:
</p>
<p>
                </p>
<blockquote class="text">
<p>C: "some line"
</p>
<p>&nbsp;&nbsp;&nbsp;"another line"
</p>
</blockquote><p>
            
</p>
<p>must actually be interpreted as client sending the following
            message:
</p>
<p>
                </p>
<blockquote class="text">
<p>"some line&lt;CR&gt;&lt;LF&gt;another
                    line&lt;CR&gt;&lt;LF&gt;"
</p>
</blockquote><p>
            
</p>
<p>where &lt;CR&gt; symbolizes the carriage return character and
            &lt;LF&gt; the line feed character as defined in the ASCII
            standard.
</p>
<p>Due to technical reasons, messages can arbitrary be
            fragmented, means the following example:
</p>
<p>
                </p>
<blockquote class="text">
<p>S: "abcd"
</p>
</blockquote><p>
            
</p>
<p>could also happen to be sent in three messages like in the
            following sequence scenario:
</p>
<p>
                </p>
<ul class="text">
<li>server sending message "a"
</li>
<li>followed by a delay (pause) with
                    arbitrary duration
</li>
<li>followed by server sending message
                    "bcd&lt;CR&gt;"
</li>
<li>again followed by a delay (pause) with arbitrary
                    duration
</li>
<li>followed by server sending the message
                    "&lt;LF&gt;"
</li>
</ul><p>
            
</p>
<p>where again &lt;CR&gt; and &lt;LF&gt; symbolize the carriage
            return and line feed characters respectively.
</p>
<a name="LSCP versioning"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.2"></a><h3>2.&nbsp;Versioning of this specification</h3>

<p>LSCP will certainly be extended and enhanced by-and-by. Each official
            release of the LSCP specification will be tagged with a unique version
            tuple. The version tuple consists at least of a major and minor version
            number like:
            
</p>
<p>
                </p>
<blockquote class="text">
<p>"1.2"
</p>
</blockquote><p>
            
</p>
<p>
            In this example the major version number would be "1" and the minor
            version number would be "2". Note that the version tuple might also
            have more than two elements. The major version number defines a
            group of backward compatible versions. That means a frontend is
            compatible to the connected sampler if and only if the LSCP versions
            to which each of the two parties complies to, match both of the
            following rules:
            
</p>
<p>Compatibility:
</p>
<p>
                </p>
<ol class="text">
<li>The frontend's LSCP major version and the sampler's LSCP
                    major version are exactly equal.
</li>
<li>The frontend's LSCP minor version is less or equal than
                    the sampler's LSCP minor version.
</li>
</ol><p>
            
</p>
<p>
            Compatibility can only be claimed if both rules are true.
            The frontend can use the
            <a class="info" href="#GET SERVER INFO">"GET SERVER INFO"<span> (</span><span class="info">General sampler informations</span><span>)</span></a> command to
            get the version of the LSCP specification the sampler complies with.
            
</p>
<a name="anchor2"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.3"></a><h3>3.&nbsp;Introduction</h3>

<p>LinuxSampler is a so called software sampler application
            capable to playback audio samples from a computer's Random
            Access Memory (RAM) as well as directly streaming it from disk.
            LinuxSampler is designed to be modular. It provides several so
            called "sampler engines" where each engine is specialized for a
            certain purpose. LinuxSampler has virtual channels which will be
            referred in this document as "sampler channels". The channels
            are in such way virtual as they can be connected to an
            arbitrary MIDI input method and arbitrary MIDI channel (e.g.
            sampler channel 17 could be connected to an ALSA sequencer
            device 64:0 and listening to MIDI channel 1 there). Each sampler
            channel will be associated with an instance of one of the available
            sampler engines (e.g. GigEngine, DLSEngine). The audio output of
            each sampler channel can be routed to an arbitrary audio output
            method (ALSA / JACK) and an arbitrary audio output channel
            there.
</p>
<a name="anchor3"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.4"></a><h3>4.&nbsp;Focus of this protocol</h3>

<p>Main focus of this protocol is to provide a way to configure
            a running LinuxSampler instance and to retrieve information
            about it. The focus of this protocol is not to provide a way to
            control synthesis parameters or even to trigger or release
            notes. Or in other words; the focus are those functionalities
            which are not covered by MIDI or which may at most be handled
            via MIDI System Exclusive Messages.
</p>
<a name="anchor4"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.5"></a><h3>5.&nbsp;Communication Overview</h3>

<p>There are two distinct methods of communication between a
            running instance of LinuxSampler and one or more control
            applications, so called "front-ends": a simple request/response
            communication method used by the clients to give commands to the
            server as well as to inquire about server's status and a
            subscribe/notify communication method used by the client to
            subscribe to and receive notifications of certain events as they
            happen on the server. The latter needs more effort to be
            implemented in the front-end application. The two communication
            methods will be described next.
</p>
<a name="anchor5"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.5.1"></a><h3>5.1.&nbsp;Request/response communication method</h3>

<p>This simple communication method is based on
                <a class="info" href="#RFC793">TCP<span> (</span><span class="info">Defense Advanced Research Projects Agency, &ldquo;TRANSMISSION CONTROL PROTOCOL,&rdquo; 1981.</span><span>)</span></a> [RFC793]. The
                front-end application establishes a TCP connection to the
                LinuxSampler instance on a certain host system. Then the
                front-end application will send certain ASCII based commands
                as defined in this document (every command line must be CRLF
                terminated - see "Conventions used in this document" at the
                beginning of this document) and the LinuxSampler application
                will response after a certain process time with an
                appropriate ASCII based answer, also as defined in this
                document. So this TCP communication is simply based on query
                and answer paradigm. That way LinuxSampler is only able to
                answer on queries from front-ends, but not able to
                automatically send messages to the client if it's not asked
                to. The fronted should not reconnect to LinuxSampler for
                every single command, instead it should keep the connection
                established and simply resend message(s) for subsequent
                commands. To keep information in the front-end up-to-date
                the front-end has to periodically send new requests to get
                the current information from the LinuxSampler instance. This
                is often referred to as "polling". While polling is simple
                to implement and may be OK to use in some cases, there may
                be disadvantages to polling such as network traffic overhead
                and information being out of date.
                It is possible for a client or several clients to open more
                than one connection to the server at the same time. It is
                also possible to send more than one request to the server
                at the same time but if those requests are sent over the
                same connection server MUST execute them sequentially. Upon
                executing a request server will produce a result set and
                send it to the client. Each and every request made by the
                client MUST result in a result set being sent back to the
                client. No other data other than a result set may be sent by
                a server to a client. No result set may be sent to a client
                without the client sending request to the server first. On
                any particular connection, result sets MUST be sent in their
                entirety without being interrupted by other result sets. If
                several requests got queued up at the server they MUST be
                processed in the order they were received and result sets
                MUST be sent back in the same order.
</p>
<a name="anchor6"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.5.1.1"></a><h3>5.1.1.&nbsp;Result format</h3>

<p>Result set could be one of the following types:
</p>
<p>
                        </p>
<ol class="text">
<li>Normal
</li>
<li>Warning
</li>
<li>Error
</li>
</ol><p>
                    
</p>
<p>Warning and Error result sets MUST be single line and
                    have the following format:
</p>
<p>
                        </p>
<ul class="text">
<li>"WRN:&lt;warning-code&gt;:&lt;warning-message&gt;"
</li>
<li>"ERR:&lt;error-code&gt;:&lt;error-message&gt;"
</li>
</ul><p>
                    
</p>
<p>Where &lt;warning-code&gt; and &lt;error-code&gt; are
                    numeric unique identifiers of the warning or error and
                    &lt;warning-message&gt; and &lt;error-message&gt; are
                    human readable descriptions of the warning or error
                    respectively.
</p>
<p>Examples:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "LOAD INSTRUMENT '/home/me/Boesendorfer24bit.gig" 0 0
</p>
<p>S: "WRN:32:This is a 24 bit patch which is not supported natively yet."
</p>
</blockquote><p>
                    
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_DRIVER_PARAMETER INFO ALSA EAR"
</p>
<p>S: "ERR:3456:Audio output driver 'ALSA' does not have a parameter 'EAR'."
</p>
</blockquote><p>
                    
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_DEVICE INFO 123456"
</p>
<p>S: "ERR:9:There is no audio output device with index 123456."
</p>
</blockquote><p>
                    
</p>
<p>Normal result sets could be:
</p>
<p>
                        </p>
<ol class="text">
<li>Empty
</li>
<li>Single line
</li>
<li>Multi-line
</li>
</ol><p>
                    
</p>
<p> Empty result set is issued when the server only
                    needed to acknowledge the fact that the request was
                    received and it was processed successfully and no
                    additional information is available. This result set has
                    the following format:
</p>
<p>
                        </p>
<blockquote class="text">
<p>"OK"
</p>
</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "SET AUDIO_OUTPUT_DEVICE_PARAMETER 0 CHANNELS=4"
</p>
<p>S: "OK"
</p>
</blockquote><p>
                    
</p>
<p>Single line result sets are command specific. One
                    example of a single line result set is an empty line.
                    Multi-line result sets are command specific and may
                    include one or more lines of information. They MUST
                    always end with the following line:
</p>
<p>
                        </p>
<blockquote class="text">
<p>"."
</p>
</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_DEVICE INFO 0"
</p>
<p>S: "DRIVER: ALSA"
</p>
<p>&nbsp;&nbsp;&nbsp;"CHANNELS: 2"
</p>
<p>&nbsp;&nbsp;&nbsp;"SAMPLERATE: 44100"
</p>
<p>&nbsp;&nbsp;&nbsp;"ACTIVE: true"
</p>
<p>&nbsp;&nbsp;&nbsp;"FRAGMENTS: 2"
</p>
<p>&nbsp;&nbsp;&nbsp;"FRAGMENTSIZE: 128"
</p>
<p>&nbsp;&nbsp;&nbsp;"CARD: '0,0'"
</p>
<p>&nbsp;&nbsp;&nbsp;"."
</p>
</blockquote><p>
                    
</p>
<p>In addition to above mentioned formats, warnings and
                    empty result sets MAY be indexed. In this case, they
                    have the following formats respectively:
</p>
<p>
                        </p>
<ul class="text">
<li>"WRN[&lt;index&gt;]:&lt;warning-code&gt;:&lt;warning-message&gt;"
</li>
<li>"OK[&lt;index&gt;]"
</li>
</ul><p>
                    
</p>
<p>where &lt;index&gt; is command specific and is used
                    to indicate channel number that the result set was
                    related to or other integer value.
</p>
<p>Each line of the result set MUST end with
                    &lt;CRLF&gt;.
</p>
<p>Examples:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "ADD CHANNEL"
</p>
<p>S: "OK[12]"
</p>
</blockquote><p>
                    
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "CREATE AUDIO_OUTPUT_DEVICE ALSA SAMPLERATE=96000"
</p>
<p>S: "WRN[0]:32:Sample rate not supported, using 44100 instead."
</p>
</blockquote><p>
                    
</p>
<a name="anchor7"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.5.2"></a><h3>5.2.&nbsp;Subscribe/notify communication method</h3>

<p>This more sophisticated communication method is actually
                only an extension of the simple request/response
                communication method. The front-end still uses a TCP
                connection and sends the same commands on the TCP
                connection. Two extra commands are SUBSCRIBE and UNSUBSCRIBE
                commands that allow a client to tell the server that it is
                interested in receiving notifications about certain events
                as they happen on the server. The SUBSCRIBE command has the
                following syntax:
</p>
<p>
                    </p>
<blockquote class="text">
<p>SUBSCRIBE &lt;event-id&gt;
</p>
</blockquote><p>
                
</p>
<p>where &lt;event-id&gt; will be replaced by the respective
                event that client wants to subscribe to. Upon receiving such
                request, server SHOULD respond with OK and start sending
                EVENT notifications when a given even has occurred to the
                front-end when an event has occurred. It MAY be possible
                certain events may be sent before OK response during real
                time nature of their generation. Event messages have the
                following format:
</p>
<p>
                    </p>
<blockquote class="text">
<p>NOTIFY:&lt;event-id&gt;:&lt;custom-event-data&gt;
</p>
</blockquote><p>
                
</p>
<p>where &lt;event-id&gt; uniquely identifies the event that
                has occurred and &lt;custom-event-data&gt; is event
                specific.
</p>
<p>Several rules must be followed by the server when
                generating events:
</p>
<p>
                    </p>
<ol class="text">
<li>Events MUST NOT be sent to any client who has not
                        issued an appropriate SUBSCRIBE command.
</li>
<li>Events MUST only be sent using the same
                        connection that was used to subscribe to them.
</li>
<li>When response is being sent to the client, event
                        MUST be inserted in the stream before or after the
                        response, but NOT in the middle. Same is true about
                        the response. It should never be inserted in the
                        middle of the event message as well as any other
                        response.
</li>
</ol><p>
                
</p>
<p>If the client is not interested in a particular event
                anymore it MAY issue UNSUBSCRIBE command using the following
                syntax:
</p>
<p>
                    </p>
<blockquote class="text">
<p>UNSUBSCRIBE &lt;event-id&gt;
</p>
</blockquote><p>
                
</p>
<p>where &lt;event-id&gt; will be replace by the respective
                event that client is no longer interested in receiving. For
                a list of supported events see <a class="info" href="#events">Section&nbsp;8<span> (</span><span class="info">Events</span><span>)</span></a>.
</p>
<p>Example: the fill states of disk stream buffers have
                changed on sampler channel 4 and the LinuxSampler instance
                will react by sending the following message to all clients
                who subscribed to this event:
</p>
<p>
                    </p>
<blockquote class="text">
<p>NOTIFY:CHANNEL_BUFFER_FILL:4 [35]62%,[33]80%,[37]98%
</p>
</blockquote><p>
                
</p>
<p>Which means there are currently three active streams on
                sampler channel 4, where the stream with ID "35" is filled
                by 62%, stream with ID 33 is filled by 80% and stream with
                ID 37 is filled by 98%.
</p>
<p>Clients may choose to open more than one connection to
                the server and use some connections to receive notifications
                while using other connections to issue commands to the
                back-end. This is entirely legal and up to the
                implementation. This does not change the protocol in any way
                and no special restrictions exist on the server to allow or
                disallow this or to track what connections belong to what
                front-ends. Server will listen on a single port, accept
                multiple connections and support protocol described in this
                specification in it's entirety on this single port on each
                connection that it accepted.
</p>
<p>Due to the fact that TCP is used for this communication,
                dead peers will be detected automatically by the OS TCP
                stack. While it may take a while to detect dead peers if no
                traffic is being sent from server to client (TCP keep-alive
                timer is set to 2 hours on many OSes) it will not be an
                issue here as when notifications are sent by the server,
                dead client will be detected quickly.
</p>
<p>When connection is closed for any reason server MUST
                forget all subscriptions that were made on this connection.
                If client reconnects it MUST resubscribe to all events that
                it wants to receive.
</p>
<a name="control_commands"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6"></a><h3>6.&nbsp;Description for control commands</h3>

<p>This chapter will describe the available control commands
            that can be sent on the TCP connection in detail. Some certain
            commands (e.g. <a class="info" href="#GET CHANNEL INFO">"GET CHANNEL INFO"<span> (</span><span class="info">Getting sampler channel information</span><span>)</span></a>
            or <a class="info" href="#GET ENGINE INFO">"GET ENGINE INFO"<span> (</span><span class="info">Getting information about an engine</span><span>)</span></a>) lead to
            multiple-line responses. In this case LinuxSampler signals the
            end of the response by a "." (single dot) line.
</p>
<a name="anchor8"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.1"></a><h3>6.1.&nbsp;Ignored lines and comments</h3>

<p>White lines, that is lines which only contain space and
                tabulator characters, and lines that start with a "#"
                character are ignored, thus it's possible for example to
                group commands and to place comments in a LSCP script
                file.
</p>
<a name="anchor9"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2"></a><h3>6.2.&nbsp;Configuring audio drivers</h3>

<p>Instances of drivers in LinuxSampler are called devices.
                You can use multiple audio devices simultaneously, e.g. to
                output the sound of one sampler channel using the ALSA audio
                output driver, and on another sampler channel you might want
                to use the JACK audio output driver. For particular audio
                output systems it's also possible to create several devices
                of the same audio output driver, e.g. two separate ALSA
                audio output devices for using two different sound cards at
                the same time. This chapter describes all commands to
                configure LinuxSampler's audio output devices and their
                parameters.
</p>
<p>Instead of defining commands and parameters for each
                driver individually, all possible parameters, their meanings
                and possible values have to be obtained at runtime. This
                makes the protocol a bit abstract, but has the advantage,
                that front-ends can be written independently of what drivers
                are currently implemented and what parameters these drivers
                are actually offering. This means front-ends can even handle
                drivers which are implemented somewhere in future without
                modifying the front-end at all.
</p>
<p>Note: examples in this chapter showing particular
                parameters of drivers are not meant as specification of the
                drivers' parameters. Driver implementations in LinuxSampler
                might have complete different parameter names and meanings
                than shown in these examples or might change in future, so
                these examples are only meant for showing how to retrieve
                what parameters drivers are offering, how to retrieve their
                possible values, etc.
</p>
<a name="GET AVAILABLE_AUDIO_OUTPUT_DRIVERS"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.1"></a><h3>6.2.1.&nbsp;Getting amount of available audio output drivers</h3>

<p>Use the following command to get the number of
                    audio output drivers currently available for the
                    LinuxSampler instance:
</p>
<p>
                        </p>
<blockquote class="text">
<p>GET AVAILABLE_AUDIO_OUTPUT_DRIVERS
</p>
</blockquote><p>
                    
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LinuxSampler will answer by sending the
                            number of audio output drivers.
</p>
</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AVAILABLE_AUDIO_OUTPUT_DRIVERS"
</p>
<p>S: "2"
</p>
</blockquote><p>
                    
</p>
<a name="LIST AVAILABLE_AUDIO_OUTPUT_DRIVERS"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.2"></a><h3>6.2.2.&nbsp;Getting all available audio output drivers</h3>

<p>Use the following command to list all audio output
                    drivers currently available for the LinuxSampler
                    instance:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LIST AVAILABLE_AUDIO_OUTPUT_DRIVERS
</p>
</blockquote><p>
                    
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LinuxSampler will answer by sending comma
                            separated character strings, each symbolizing an
                            audio output driver.
</p>
</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "LIST AVAILABLE_AUDIO_OUTPUT_DRIVERS"
</p>
<p>S: "ALSA,JACK"
</p>
</blockquote><p>
                    
</p>
<a name="GET AUDIO_OUTPUT_DRIVER INFO"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.3"></a><h3>6.2.3.&nbsp;Getting information about a specific audio
                output driver</h3>

<p>Use the following command to get detailed information
                    about a specific audio output driver:
</p>
<p>
                        </p>
<blockquote class="text">
<p>GET AUDIO_OUTPUT_DRIVER INFO
                             &lt;audio-output-driver&gt;
</p>
</blockquote><p>
                    
</p>
<p>Where &lt;audio-output-driver&gt; is the name of the
                    audio output driver, returned by the
                    <a class="info" href="#LIST AVAILABLE_AUDIO_OUTPUT_DRIVERS">"LIST AVAILABLE_AUDIO_OUTPUT_DRIVERS"<span> (</span><span class="info">Getting all available audio output drivers</span><span>)</span></a> command.
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LinuxSampler will answer by sending a
                            &lt;CRLF&gt; separated list. Each answer line
                            begins with the information category name
                            followed by a colon and then a space character
                            &lt;SP&gt; and finally the info character string
                            to that info category. At the moment the
                            following information categories are
                            defined:
</p>
<p>
                              </p>
<blockquote class="text">
<p>DESCRIPTION -
                                    </p>
<blockquote class="text">
<p> character string describing the
                                      audio output driver
</p>
</blockquote>
                                  

<p>VERSION -
                                    </p>
<blockquote class="text">
<p>character string reflecting the
                                      driver's version
</p>
</blockquote>
                                  

<p>PARAMETERS -
                                    </p>
<blockquote class="text">
<p>comma separated list of all
                                      parameters available for the given
                                      audio output driver, at least
                                      parameters 'channels', 'samplerate'
                                      and 'active' are offered by all audio
                                      output drivers
</p>
</blockquote>
                                  

</blockquote>
                            

<p>The mentioned fields above don't have to be
                            in particular order.
</p>
</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                      </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_DRIVER INFO ALSA"
</p>
<p>S: "DESCRIPTION: Advanced Linux Sound
                          Architecture"
</p>
<p>&nbsp;&nbsp;&nbsp;"VERSION: 1.0"
</p>
<p>&nbsp;&nbsp;&nbsp;"PARAMETERS:
                          DRIVER,CHANNELS,SAMPLERATE,ACTIVE,FRAGMENTS,
                          FRAGMENTSIZE,CARD"
</p>
<p>&nbsp;&nbsp;&nbsp;"."
</p>
</blockquote><p>
                    
</p>
<a name="GET AUDIO_OUTPUT_DRIVER_PARAMETER INFO"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.4"></a><h3>6.2.4.&nbsp;Getting information about specific audio
                output driver parameter</h3>

<p>Use the following command to get detailed information
                    about a  specific audio output driver parameter:
</p>
<p>
                        </p>
<blockquote class="text">
<p>GET AUDIO_OUTPUT_DRIVER_PARAMETER INFO &lt;audio&gt; &lt;prm&gt; [&lt;deplist&gt;]
</p>
</blockquote><p>
                    
</p>
<p>Where &lt;audio&gt; is the name of the audio output
                    driver as returned by the <a class="info" href="#LIST AVAILABLE_AUDIO_OUTPUT_DRIVERS">"LIST AVAILABLE_AUDIO_OUTPUT_DRIVERS"<span> (</span><span class="info">Getting all available audio output drivers</span><span>)</span></a> command,
                    &lt;prm&gt; a specific parameter name for which information should be
                    obtained (as returned by the
                    <a class="info" href="#GET AUDIO_OUTPUT_DRIVER INFO">"GET AUDIO_OUTPUT_DRIVER INFO"<span> (</span><span class="info">Getting information about a specific audio                 output driver</span><span>)</span></a> command) and
                    &lt;deplist&gt; is an optional list of parameters on which the sought
                    parameter &lt;prm&gt; depends on, &lt;deplist&gt; is a list of key-value
                    pairs in form of "key1=val1 key2=val2 ...", where character string values
                    are encapsulated into apostrophes ('). Arguments given with &lt;deplist&gt;
                    which are not dependency parameters of &lt;prm&gt; will be ignored, means
                    the front-end application can simply put all parameters into &lt;deplist&gt;
                    with the values already selected by the user.
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LinuxSampler will answer by sending a
                            &lt;CRLF&gt; separated list.
                            Each answer line begins with the information category name
                            followed by a colon and then a space character &lt;SP&gt; and
                            finally
                            the info character string to that info category. There are
                            information which is always returned, independently of the
                            given driver parameter and there are optional information
                            which is only shown dependently to given driver parameter. At
                            the moment the following information categories are defined:
</p>
</blockquote><p>
                    
</p>
<p>
                        </p>
<blockquote class="text">
<p>TYPE -
                              </p>
<blockquote class="text">
<p>either "BOOL" for boolean value(s) or
                                "INT" for integer
                                value(s) or "FLOAT" for dotted number(s) or "STRING" for
                                character string(s)
                                (always returned, no matter which driver parameter)
</p>
</blockquote>
                            

<p>DESCRIPTION -
                              </p>
<blockquote class="text">
<p>arbitrary text describing the purpose of the parameter
                                (always returned, no matter which driver parameter)
</p>
</blockquote>
                            

<p>MANDATORY -
                              </p>
<blockquote class="text">
<p>either true or false, defines if this parameter must be
                                given when the device is to be created with the
                                <a class="info" href="#CREATE AUDIO_OUTPUT_DEVICE">'CREATE AUDIO_OUTPUT_DEVICE'<span> (</span><span class="info">Creating an audio output device</span><span>)</span></a>
                                command (always returned, no matter which driver parameter)
</p>
</blockquote>
                            

<p>FIX -
                              </p>
<blockquote class="text">
<p>either true or false, if false then this parameter can
                                be changed at any time, once the device is created by
                                the <a class="info" href="#CREATE AUDIO_OUTPUT_DEVICE">'CREATE AUDIO_OUTPUT_DEVICE'<span> (</span><span class="info">Creating an audio output device</span><span>)</span></a>
                                command (always returned, no matter which driver parameter)
</p>
</blockquote>
                            

<p>MULTIPLICITY -
                              </p>
<blockquote class="text">
<p>either true or false, defines if this parameter allows
                                only one value or a list of values, where true means
                                multiple values and false only a single value allowed
                                (always returned, no matter which driver parameter)
</p>
</blockquote>
                            

<p>DEPENDS -
                              </p>
<blockquote class="text">
<p>comma separated list of parameters this parameter depends
                                on, means the values for fields 'DEFAULT', 'RANGE_MIN',
                                'RANGE_MAX' and 'POSSIBILITIES' might depend on these
                                listed parameters, for example assuming that an audio
                                driver (like the ALSA driver) offers parameters 'card'
                                and 'samplerate' then parameter 'samplerate' would
                                depend on 'card' because the possible values for
                                'samplerate' depends on the sound card which can be
                                chosen by the 'card' parameter
                                (optionally returned, dependent to driver parameter)
</p>
</blockquote>
                            

<p>DEFAULT -
                              </p>
<blockquote class="text">
<p>reflects the default value for this parameter which is
                                used when the device is created and not explicitly
                                given with the <a class="info" href="#CREATE AUDIO_OUTPUT_DEVICE">'CREATE AUDIO_OUTPUT_DEVICE'<span> (</span><span class="info">Creating an audio output device</span><span>)</span></a> command,
                                in case of MULTIPLCITY=true, this is a comma separated
                                list, that's why character strings are encapsulated into
                                apostrophes (')
                                (optionally returned, dependent to driver parameter)
</p>
</blockquote>
                            

<p>RANGE_MIN -
                              </p>
<blockquote class="text">
<p>defines lower limit of the allowed value range for this
                                parameter, can be an integer value as well as a dotted
                                number, this parameter is often used in conjunction
                                with RANGE_MAX, but may also appear without
                                (optionally returned, dependent to driver parameter)
</p>
</blockquote>
                            

<p>RANGE_MAX -
                              </p>
<blockquote class="text">
<p>defines upper limit of the allowed value range for this
                                parameter, can be an integer value as well as a dotted
                                number, this parameter is often used in conjunction with
                                RANGE_MIN, but may also appear without
                                (optionally returned, dependent to driver parameter)
</p>
</blockquote>
                            

<p>POSSIBILITIES -
                              </p>
<blockquote class="text">
<p>comma separated list of possible values for this
                                parameter, character strings are encapsulated into
                                apostrophes
                                (optionally returned, dependent to driver parameter)
</p>
</blockquote>
                            

</blockquote><p>
                    
</p>
<p>The mentioned fields above don't have to be in particular order.
</p>
<p>Examples:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_DRIVER_PARAMETER INFO ALSA CARD"
</p>
<p>S: "DESCRIPTION: sound card to be used"
</p>
<p>&nbsp;&nbsp;&nbsp;"TYPE: STRING"
</p>
<p>&nbsp;&nbsp;&nbsp;"MANDATORY: false"
</p>
<p>&nbsp;&nbsp;&nbsp;"FIX: true"
</p>
<p>&nbsp;&nbsp;&nbsp;"MULTIPLICITY: false"
</p>
<p>&nbsp;&nbsp;&nbsp;"DEFAULT: '0,0'"
</p>
<p>&nbsp;&nbsp;&nbsp;"POSSIBILITIES: '0,0','1,0','2,0'"
</p>
<p>&nbsp;&nbsp;&nbsp;"."
</p>
</blockquote><p>
                    
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_DRIVER_PARAMETER INFO ALSA SAMPLERATE"
</p>
<p>S: "DESCRIPTION: output sample rate in Hz"
</p>
<p>&nbsp;&nbsp;&nbsp;"TYPE: INT"
</p>
<p>&nbsp;&nbsp;&nbsp;"MANDATORY: false"
</p>
<p>&nbsp;&nbsp;&nbsp;"FIX: false"
</p>
<p>&nbsp;&nbsp;&nbsp;"MULTIPLICITY: false"
</p>
<p>&nbsp;&nbsp;&nbsp;"DEPENDS: card"
</p>
<p>&nbsp;&nbsp;&nbsp;"DEFAULT: 44100"
</p>
<p>&nbsp;&nbsp;&nbsp;"."
</p>
</blockquote><p>
                    
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_DRIVER_PARAMETER INFO ALSA SAMPLERATE CARD='0,0'"
</p>
<p>S: "DESCRIPTION: output sample rate in Hz"
</p>
<p>&nbsp;&nbsp;&nbsp;"TYPE: INT"
</p>
<p>&nbsp;&nbsp;&nbsp;"MANDATORY: false"
</p>
<p>&nbsp;&nbsp;&nbsp;"FIX: false"
</p>
<p>&nbsp;&nbsp;&nbsp;"MULTIPLICITY: false"
</p>
<p>&nbsp;&nbsp;&nbsp;"DEPENDS: card"
</p>
<p>&nbsp;&nbsp;&nbsp;"DEFAULT: 44100"
</p>
<p>&nbsp;&nbsp;&nbsp;"RANGE_MIN: 22050"
</p>
<p>&nbsp;&nbsp;&nbsp;"RANGE_MAX: 96000"
</p>
<p>&nbsp;&nbsp;&nbsp;"."
</p>
</blockquote><p>
                    
</p>
<a name="CREATE AUDIO_OUTPUT_DEVICE"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.5"></a><h3>6.2.5.&nbsp;Creating an audio output device</h3>

<p>Use the following command to create a new audio output device for  the desired audio output system:
</p>
<p>
                        </p>
<blockquote class="text">
<p>CREATE AUDIO_OUTPUT_DEVICE &lt;audio-output-driver&gt; [&lt;param-list&gt;]
</p>
</blockquote><p>
                    
</p>
<p>Where &lt;audio-output-driver&gt; should be replaced by the desired audio
                    output system as returned by the
                    <a class="info" href="#LIST AVAILABLE_AUDIO_OUTPUT_DRIVERS">"LIST AVAILABLE_AUDIO_OUTPUT_DRIVERS"<span> (</span><span class="info">Getting all available audio output drivers</span><span>)</span></a>
                    command and &lt;param-list&gt; by an optional list of driver
                    specific parameters in form of "key1=val1 key2=val2 ...", where
                    character string values should be encapsulated into apostrophes (').
                    Note that there might be drivers which require parameter(s) to be
                    given with this command. Use the previously described commands in
                    this chapter to get this information.
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>"OK[&lt;device-id&gt;]" -
                                </p>
<blockquote class="text">
<p>in case the device was successfully created, where
                                    &lt;device-id&gt; is the numerical ID of the new device
</p>
</blockquote>
                            

<p>"WRN[&lt;device-id&gt;]:&lt;warning-code&gt;:&lt;warning-message&gt;" -
                                </p>
<blockquote class="text">
<p>in case the device was created successfully, where
                                    &lt;device-id&gt; is the numerical ID of the new device, but there
                                    are noteworthy issue(s) related (e.g. sound card doesn't
                                    support given hardware parameters and the driver is using
                                    fall-back values), providing an appropriate warning code and
                                    warning message
</p>
</blockquote>
                            

<p>"ERR:&lt;error-code&gt;:&lt;error-message&gt;" -
                                </p>
<blockquote class="text">
<p>in case it failed, providing an appropriate error code and error message
</p>
</blockquote>
                            

</blockquote><p>
                    
</p>
<p>Examples:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "CREATE AUDIO_OUTPUT_DEVICE ALSA"
</p>
<p>S: "OK[0]"
</p>
</blockquote><p>
                    
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "CREATE AUDIO_OUTPUT_DEVICE ALSA CARD='2,0' SAMPLERATE=96000"
</p>
<p>S: "OK[1]"
</p>
</blockquote><p>
                    
</p>
<a name="DESTROY AUDIO_OUTPUT_DEVICE"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.6"></a><h3>6.2.6.&nbsp;Destroying an audio output device</h3>

<p>Use the following command to destroy a created output device:
</p>
<p>
                        </p>
<blockquote class="text">
<p>DESTROY AUDIO_OUTPUT_DEVICE &lt;device-id&gt;
</p>
</blockquote><p>
                    
</p>
<p>Where &lt;device-id&gt; should be replaced by the numerical ID of the
                    audio output device as given by the
                    <a class="info" href="#CREATE AUDIO_OUTPUT_DEVICE">"CREATE AUDIO_OUTPUT_DEVICE"<span> (</span><span class="info">Creating an audio output device</span><span>)</span></a>
                    or <a class="info" href="#LIST AUDIO_OUTPUT_DEVICES">"LIST AUDIO_OUTPUT_DEVICES"<span> (</span><span class="info">Getting all created audio output device list</span><span>)</span></a>
                    command.
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>"OK" -
                                </p>
<blockquote class="text">
<p>in case the device was successfully destroyed
</p>
</blockquote>
                            

<p>"WRN:&lt;warning-code&gt;:&lt;warning-message&gt;" -
                                </p>
<blockquote class="text">
<p>in case the device was destroyed successfully, but there are
                                    noteworthy issue(s) related (e.g. an audio over ethernet
                                    driver was unloaded but the other host might not be
                                    informed about this situation), providing an appropriate
                                    warning code and warning message
</p>
</blockquote>
                            

<p>"ERR:&lt;error-code&gt;:&lt;error-message&gt;" -
                                </p>
<blockquote class="text">
<p>in case it failed, providing an appropriate error code and
                                    error message
</p>
</blockquote>
                            

</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "DESTROY AUDIO_OUTPUT_DEVICE 0"
</p>
<p>S: "OK"
</p>
</blockquote><p>
                    
</p>
<a name="GET AUDIO_OUTPUT_DEVICES"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.7"></a><h3>6.2.7.&nbsp;Getting all created audio output device count</h3>

<p>Use the following command to count all created audio output devices:
</p>
<p>
                        </p>
<blockquote class="text">
<p>GET AUDIO_OUTPUT_DEVICES
</p>
</blockquote><p>
                    
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LinuxSampler will answer by sending the current number of all
                            audio output devices.
</p>
</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_DEVICES"
</p>
<p>S: "4"
</p>
</blockquote><p>
                    
</p>
<a name="LIST AUDIO_OUTPUT_DEVICES"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.8"></a><h3>6.2.8.&nbsp;Getting all created audio output device list</h3>

<p>Use the following command to list all created audio output devices:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LIST AUDIO_OUTPUT_DEVICES
</p>
</blockquote><p>
                    
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LinuxSampler will answer by sending a comma separated list with
                            the numerical IDs of all audio output devices.
</p>
</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "LIST AUDIO_OUTPUT_DEVICES"
</p>
<p>S: "0,1,4,5"
</p>
</blockquote><p>
                    
</p>
<a name="GET AUDIO_OUTPUT_DEVICE INFO"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.9"></a><h3>6.2.9.&nbsp;Getting current settings of an audio output device</h3>

<p>Use the following command to get current settings of a specific, created audio output device:
</p>
<p>
                        </p>
<blockquote class="text">
<p>GET AUDIO_OUTPUT_DEVICE INFO &lt;device-id&gt;
</p>
</blockquote><p>
                    
</p>
<p>Where &lt;device-id&gt; should be replaced by numerical ID
                    of the audio output device as e.g. returned by the
                    <a class="info" href="#LIST AUDIO_OUTPUT_DEVICES">"LIST AUDIO_OUTPUT_DEVICES"<span> (</span><span class="info">Getting all created audio output device list</span><span>)</span></a> command.
</p>
<p>Possible Answers:
</p>
<p>LinuxSampler will answer by sending a &lt;CRLF&gt; separated list.
                    Each answer line begins with the information category name
                    followed by a colon and then a space character &lt;SP&gt; and finally
                    the info character string to that info category. As some
                    parameters might allow multiple values, character strings are
                    encapsulated into apostrophes ('). At the moment the following
                    information categories are defined (independently of device):
</p>
<p>
                        </p>
<blockquote class="text">
<p>DRIVER -
                                </p>
<blockquote class="text">
<p>identifier of the used audio output driver, as also
                                    returned by the
                                    <a class="info" href="#LIST AVAILABLE_AUDIO_OUTPUT_DRIVERS">"LIST AVAILABLE_AUDIO_OUTPUT_DRIVERS"<span> (</span><span class="info">Getting all available audio output drivers</span><span>)</span></a>
                                    command
</p>
</blockquote>
                            

<p>CHANNELS -
                                </p>
<blockquote class="text">
<p>amount of audio output channels this device currently
                                    offers
</p>
</blockquote>
                            

<p>SAMPLERATE -
                                </p>
<blockquote class="text">
<p>playback sample rate the device uses
</p>
</blockquote>
                            

<p>ACTIVE -
                                </p>
<blockquote class="text">
<p>either true or false, if false then the audio device is
                                    inactive and doesn't output any sound, nor do the
                                    sampler channels connected to this audio device render
                                    any audio
</p>
</blockquote>
                            

</blockquote><p>
                    
</p>
<p>The mentioned fields above don't have to be in particular
                    order. The fields above are only those fields which are
                    returned by all audio output devices. Every audio output driver
                    might have its own, additional driver specific parameters (see
                    <a class="info" href="#GET AUDIO_OUTPUT_DRIVER INFO">Section&nbsp;6.2.3<span> (</span><span class="info">Getting information about a specific audio                 output driver</span><span>)</span></a>)
                    which are also returned by this command.
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_DEVICE INFO 0"
</p>
<p>S: "DRIVER: ALSA"
</p>
<p>&nbsp;&nbsp;&nbsp;"CHANNELS: 2"
</p>
<p>&nbsp;&nbsp;&nbsp;"SAMPLERATE: 44100"
</p>
<p>&nbsp;&nbsp;&nbsp;"ACTIVE: true"
</p>
<p>&nbsp;&nbsp;&nbsp;"FRAGMENTS: 2"
</p>
<p>&nbsp;&nbsp;&nbsp;"FRAGMENTSIZE: 128"
</p>
<p>&nbsp;&nbsp;&nbsp;"CARD: '0,0'"
</p>
<p>&nbsp;&nbsp;&nbsp;"."
</p>
</blockquote><p>
                    
</p>
<a name="SET AUDIO_OUTPUT_DEVICE_PARAMETER"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.10"></a><h3>6.2.10.&nbsp;Changing settings of audio output devices</h3>

<p>Use the following command to alter a specific setting of a created audio output device:
</p>
<p>
                        </p>
<blockquote class="text">
<p>SET AUDIO_OUTPUT_DEVICE_PARAMETER &lt;device-id&gt; &lt;key&gt;=&lt;value&gt;
</p>
</blockquote><p>
                    
</p>
<p>Where &lt;device-id&gt; should be replaced by the numerical ID of the
                    audio output device as given by the
                    <a class="info" href="#CREATE AUDIO_OUTPUT_DEVICE">"CREATE AUDIO_OUTPUT_DEVICE"<span> (</span><span class="info">Creating an audio output device</span><span>)</span></a>
                    or <a class="info" href="#LIST AUDIO_OUTPUT_DEVICES">"LIST AUDIO_OUTPUT_DEVICES"<span> (</span><span class="info">Getting all created audio output device list</span><span>)</span></a>
                    command, &lt;key&gt; by the name of the parameter to change
                    and &lt;value&gt; by the new value for this parameter.
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>"OK" -
                                </p>
<blockquote class="text">
<p>in case setting was successfully changed
</p>
</blockquote>
                            

<p>"WRN:&lt;warning-code&gt;:&lt;warning-message&gt;" -
                                </p>
<blockquote class="text">
<p>in case setting was changed successfully, but there are
                                    noteworthy issue(s) related, providing an appropriate
                                    warning code and warning message
</p>
</blockquote>
                            

<p>"ERR:&lt;error-code&gt;:&lt;error-message&gt;" -
                                </p>
<blockquote class="text">
<p>in case it failed, providing an appropriate error code and
                                    error message
</p>
</blockquote>
                            

</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "SET AUDIO_OUTPUT_DEVICE_PARAMETER 0 FRAGMENTSIZE=128"
</p>
<p>S: "OK"
</p>
</blockquote><p>
                    
</p>
<a name="GET AUDIO_OUTPUT_CHANNEL INFO"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.11"></a><h3>6.2.11.&nbsp;Getting information about an audio channel</h3>

<p>Use the following command to get information about an audio channel:
</p>
<p>
                        </p>
<blockquote class="text">
<p>GET AUDIO_OUTPUT_CHANNEL INFO &lt;device-id&gt; &lt;audio-chan&gt;
</p>
</blockquote><p>
                    
</p>
<p>Where &lt;device-id&gt; is the numerical ID of the audio output device as given by the
                    <a class="info" href="#CREATE AUDIO_OUTPUT_DEVICE">"CREATE AUDIO_OUTPUT_DEVICE"<span> (</span><span class="info">Creating an audio output device</span><span>)</span></a>
                    or <a class="info" href="#LIST AUDIO_OUTPUT_DEVICES">"LIST AUDIO_OUTPUT_DEVICES"<span> (</span><span class="info">Getting all created audio output device list</span><span>)</span></a>
                    command and &lt;audio-chan&gt; the audio channel number.
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LinuxSampler will answer by sending a &lt;CRLF&gt; separated list.
                            Each answer line begins with the information category name
                            followed by a colon and then a space character &lt;SP&gt; and finally
                            the info character string to that info category. At the moment
                            the following information categories are defined:
</p>
<p>
                                </p>
<blockquote class="text">
<p>NAME -
                                        </p>
<blockquote class="text">
<p>arbitrary character string naming the channel, which
                                            doesn't have to be unique (always returned by all audio channels)
</p>
</blockquote>
                                    

<p>IS_MIX_CHANNEL -
                                        </p>
<blockquote class="text">
<p>either true or false, a mix-channel is not a real,
                                            independent audio channel, but a virtual channel which
                                            is mixed to another real channel, this mechanism is
                                            needed for sampler engines which need more audio
                                            channels than the used audio system might be able to offer
                                            (always returned by all audio channels)
</p>
</blockquote>
                                    

<p>MIX_CHANNEL_DESTINATION -
                                        </p>
<blockquote class="text">
<p>numerical ID (positive integer including 0)
                                            which reflects the real audio channel (of the same audio
                                            output device) this mix channel refers to, means where
                                            the audio signal actually will be routed / added to
                                            (only returned in case the audio channel is mix channel)
</p>
</blockquote>
                                    

</blockquote>
                            

</blockquote><p>
                    
</p>
<p>The mentioned fields above don't have to be in particular
                    order. The fields above are only those fields which are
                    generally returned for the described cases by all audio
                    channels regardless of the audio driver. Every audio channel
                    might have its own, additional driver and channel specific
                    parameters.
</p>
<p>Examples:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_CHANNEL INFO 0 0"
</p>
<p>S: "NAME: studio monitor left"
</p>
<p>&nbsp;&nbsp;&nbsp;"IS_MIX_CHANNEL: false"
</p>
<p>&nbsp;&nbsp;&nbsp;"."
</p>
</blockquote><p>
                    
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_CHANNEL INFO 0 1"
</p>
<p>S: "NAME: studio monitor right"
</p>
<p>&nbsp;&nbsp;&nbsp;"IS_MIX_CHANNEL: false"
</p>
<p>&nbsp;&nbsp;&nbsp;"."
</p>
</blockquote><p>
                    
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_CHANNEL INFO 0 2"
</p>
<p>S: "NAME: studio monitor left"
</p>
<p>&nbsp;&nbsp;&nbsp;"IS_MIX_CHANNEL: true"
</p>
<p>&nbsp;&nbsp;&nbsp;"MIX_CHANNEL_DESTINATION: 1"
</p>
<p>&nbsp;&nbsp;&nbsp;"."
</p>
</blockquote><p>
                    
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_CHANNEL INFO 1 0"
</p>
<p>S: "NAME: 'ardour (left)'"
</p>
<p>&nbsp;&nbsp;&nbsp;"IS_MIX_CHANNEL: false"
</p>
<p>&nbsp;&nbsp;&nbsp;"JACK_BINDINGS: 'ardour:0'"
</p>
<p>&nbsp;&nbsp;&nbsp;"."
</p>
</blockquote><p>
                    
</p>
<a name="GET AUDIO_OUTPUT_CHANNEL_PARAMETER INFO"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.12"></a><h3>6.2.12.&nbsp;Getting information about specific audio channel parameter</h3>

<p>Use the following command to get detailed information about specific audio channel parameter:
</p>
<p>
                        </p>
<blockquote class="text">
<p>GET AUDIO_OUTPUT_CHANNEL_PARAMETER INFO &lt;dev-id&gt; &lt;chan&gt; &lt;param&gt;
</p>
</blockquote><p>
                    
</p>
<p>Where &lt;dev-id&gt; is the numerical ID of the audio output device as returned by the
                    <a class="info" href="#CREATE AUDIO_OUTPUT_DEVICE">"CREATE AUDIO_OUTPUT_DEVICE"<span> (</span><span class="info">Creating an audio output device</span><span>)</span></a>
                    or <a class="info" href="#LIST AUDIO_OUTPUT_DEVICES">"LIST AUDIO_OUTPUT_DEVICES"<span> (</span><span class="info">Getting all created audio output device list</span><span>)</span></a>
                    command, &lt;chan&gt; the audio channel number
                    and &lt;param&gt; a specific channel parameter name for which information should
                    be obtained (as returned by the <a class="info" href="#GET AUDIO_OUTPUT_CHANNEL INFO">"GET AUDIO_OUTPUT_CHANNEL INFO"<span> (</span><span class="info">Getting information about an audio channel</span><span>)</span></a> command).
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LinuxSampler will answer by sending a &lt;CRLF&gt; separated list.
                            Each answer line begins with the information category name
                            followed by a colon and then a space character &lt;SP&gt; and finally
                            the info character string to that info category. There are
                            information which is always returned, independently of the
                            given channel parameter and there is optional information
                            which is only shown dependently to the given audio channel. At
                            the moment the following information categories are defined:
</p>
<p>
                                </p>
<blockquote class="text">
<p>TYPE -
                                        </p>
<blockquote class="text">
<p>either "BOOL" for boolean value(s) or "INT" for integer
                                            value(s) or "FLOAT" for dotted number(s) or "STRING" for
                                            character string(s)
                                            (always returned)
</p>
</blockquote>
                                    

<p>DESCRIPTION -
                                        </p>
<blockquote class="text">
<p>arbitrary text describing the purpose of the parameter (always returned)
</p>
</blockquote>
                                    

<p>FIX -
                                        </p>
<blockquote class="text">
<p>either true or false, if true then this parameter is
                                            read only, thus cannot be altered
                                            (always returned)
</p>
</blockquote>
                                    

<p>MULTIPLICITY -
                                        </p>
<blockquote class="text">
<p>either true or false, defines if this parameter allows
                                            only one value or a list of values, where true means
                                            multiple values and false only a single value allowed
                                            (always returned)
</p>
</blockquote>
                                    

<p>RANGE_MIN -
                                        </p>
<blockquote class="text">
<p>defines lower limit of the allowed value range for this
                                            parameter, can be an integer value as well as a dotted
                                            number, usually used in conjunction with 'RANGE_MAX',
                                            but may also appear without
                                            (optionally returned, dependent to driver and channel
                                            parameter)
</p>
</blockquote>
                                    

<p>RANGE_MAX -
                                        </p>
<blockquote class="text">
<p>defines upper limit of the allowed value range for this
                                            parameter, can be an integer value as well as a dotted
                                            number, usually used in conjunction with 'RANGE_MIN',
                                            but may also appear without
                                            (optionally returned, dependent to driver and channel
                                            parameter)
</p>
</blockquote>
                                    

<p>POSSIBILITIES -
                                        </p>
<blockquote class="text">
<p>comma separated list of possible values for this
                                            parameter, character strings are encapsulated into
                                            apostrophes
                                            (optionally returned, dependent to driver and channel
                                            parameter)
</p>
</blockquote>
                                    

</blockquote>
                            

<p>The mentioned fields above don't have to be in particular order.
</p>
</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AUDIO_OUTPUT_CHANNEL_PARAMETER INFO 1 0 JACK_BINDINGS"
</p>
<p>S: "DESCRIPTION: bindings to other JACK clients"
</p>
<p>&nbsp;&nbsp;&nbsp;"TYPE: STRING"
</p>
<p>&nbsp;&nbsp;&nbsp;"FIX: false"
</p>
<p>&nbsp;&nbsp;&nbsp;"MULTIPLICITY: true"
</p>
<p>&nbsp;&nbsp;&nbsp;"POSSIBILITIES: 'PCM:0','PCM:1','ardour:0','ardour:1'"
</p>
<p>&nbsp;&nbsp;&nbsp;"."
</p>
</blockquote><p>
                    
</p>
<a name="SET AUDIO_OUTPUT_CHANNEL_PARAMETER"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.2.13"></a><h3>6.2.13.&nbsp;Changing settings of audio output channels</h3>

<p>Use the following command to alter a specific setting of an audio output channel:
</p>
<p>
                        </p>
<blockquote class="text">
<p>SET AUDIO_OUTPUT_CHANNEL_PARAMETER &lt;dev-id&gt; &lt;chn&gt; &lt;key&gt;=&lt;value&gt;
</p>
</blockquote><p>
                    
</p>
<p>Where &lt;dev-id&gt; should be replaced by the numerical ID of the audio output device as returned by the
                    <a class="info" href="#CREATE AUDIO_OUTPUT_DEVICE">"CREATE AUDIO_OUTPUT_DEVICE"<span> (</span><span class="info">Creating an audio output device</span><span>)</span></a>
                    or <a class="info" href="#LIST AUDIO_OUTPUT_DEVICES">"LIST AUDIO_OUTPUT_DEVICES"<span> (</span><span class="info">Getting all created audio output device list</span><span>)</span></a>
                    command, &lt;chn&gt; by the audio channel number, &lt;key&gt; by the name of the
                    parameter to change and &lt;value&gt; by the new value for this parameter.
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>"OK" -
                                </p>
<blockquote class="text">
<p>in case setting was successfully changed
</p>
</blockquote>
                            

<p>"WRN:&lt;warning-code&gt;:&lt;warning-message&gt;" -
                                </p>
<blockquote class="text">
<p>in case setting was changed successfully, but there are
                                   noteworthy issue(s) related, providing an appropriate
                                   warning code and warning message
</p>
</blockquote>
                            

<p>"ERR:&lt;error-code&gt;:&lt;error-message&gt;" -
                                </p>
<blockquote class="text">
<p>in case it failed, providing an appropriate error code and
                                   error message
</p>
</blockquote>
                            

</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "SET AUDIO_OUTPUT_CHANNEL PARAMETER 0 0 JACK_BINDINGS='PCM:0'"
</p>
<p>S: "OK"
</p>
</blockquote><p>
                    
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "SET AUDIO_OUTPUT_CHANNEL PARAMETER 0 0 NAME='monitor left'"
</p>
<p>S: "OK"
</p>
</blockquote><p>
                    
</p>
<a name="anchor10"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.3"></a><h3>6.3.&nbsp;Configuring MIDI input drivers</h3>

<p>Instances of drivers in LinuxSampler are called devices. You can use
                multiple MIDI devices simultaneously, e.g. to use MIDI over ethernet as
                MIDI input on one sampler channel and ALSA as MIDI input on another sampler
                channel. For particular MIDI input systems it's also possible to create
                several devices of the same MIDI input type. This chapter describes all
                commands to configure LinuxSampler's MIDI input devices and their parameters.
</p>
<p>Instead of defining commands and parameters for each driver individually,
                all possible parameters, their meanings and possible values have to be obtained
                at runtime. This makes the protocol a bit abstract, but has the advantage, that
                front-ends can be written independently of what drivers are currently implemented
                and what parameters these drivers are actually offering. This means front-ends can
                even handle drivers which are implemented somewhere in future without modifying
                the front-end at all.
</p>
<p>Commands for configuring MIDI input devices are pretty much the same as the
                commands for configuring audio output drivers, already described in the last
                chapter.
</p>
<p>Note: examples in this chapter showing particular parameters of drivers are
                not meant as specification of the drivers' parameters. Driver implementations in
                LinuxSampler might have complete different parameter names and meanings than shown
                in these examples or might change in future, so these examples are only meant for
                showing how to retrieve what parameters drivers are offering, how to retrieve their
                possible values, etc.
</p>
<a name="GET AVAILABLE_MIDI_INPUT_DRIVERS"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.3.1"></a><h3>6.3.1.&nbsp;Getting amount of available MIDI input drivers</h3>

<p>Use the following command to get the number of
                    MIDI input drivers currently available for the
                    LinuxSampler instance:
</p>
<p>
                        </p>
<blockquote class="text">
<p>GET AVAILABLE_MIDI_INPUT_DRIVERS
</p>
</blockquote><p>
                    
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LinuxSampler will answer by sending the
                            number of available MIDI input drivers.
</p>
</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "GET AVAILABLE_MIDI_INPUT_DRIVERS"
</p>
<p>S: "2"
</p>
</blockquote><p>
                    
</p>
<a name="LIST AVAILABLE_MIDI_INPUT_DRIVERS"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.3.2"></a><h3>6.3.2.&nbsp;Getting all available MIDI input drivers</h3>

<p>Use the following command to list all MIDI input drivers currently available
                    for the LinuxSampler instance:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LIST AVAILABLE_MIDI_INPUT_DRIVERS
</p>
</blockquote><p>
                    
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LinuxSampler will answer by sending comma separated character
                            strings, each symbolizing a MIDI input driver.
</p>
</blockquote><p>
                    
</p>
<p>Example:
</p>
<p>
                        </p>
<blockquote class="text">
<p>C: "LIST AVAILABLE_MIDI_INPUT_DRIVERS"
</p>
<p>S: "ALSA,JACK"
</p>
</blockquote><p>
                    
</p>
<a name="GET MIDI_INPUT_DRIVER INFO"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="bug" align="right"><tr><td class="bug"><a href="#toc" class="link2">&nbsp;TOC&nbsp;</a></td></tr></table>
<a name="rfc.section.6.3.3"></a><h3>6.3.3.&nbsp;Getting information about a specific MIDI input driver</h3>

<p>Use the following command to get detailed information about a specific MIDI input driver:
</p>
<p>
                        </p>
<blockquote class="text">
<p>GET MIDI_INPUT_DRIVER INFO &lt;midi-input-driver&gt;
</p>
</blockquote><p>
                    
</p>
<p>Where &lt;midi-input-driver&gt; is the name of the MIDI input driver as returned
                    by the <a class="info" href="#LIST AVAILABLE_MIDI_INPUT_DRIVERS">"LIST AVAILABLE_MIDI_INPUT_DRIVERS"<span> (</span><span class="info">Getting all available MIDI input drivers</span><span>)</span></a> command.
</p>
<p>Possible Answers:
</p>
<p>
                        </p>
<blockquote class="text">
<p>LinuxSampler will answer by sending a &lt;CRLF&gt; separated list.
                            Each answer line begins with the information category name
                            followed by a colon and then a space character &lt;SP&gt; and finally
                            the info character string to that info category. At the moment
                            the following information categories are defined:
</p>
<p>
                                </p>
<blockquote class="text">
<p>DESCRIPTION -
                                        </p>
<blockquote class="text">
<p>arbitrary description text about the MIDI input driver
</p>
</blockquote>
                                    

<p>VERSION -
                                        </p>
<blockquote class="text">
<p>arbitrary character string regarding the driver's version
</p>