manual/_manual/22_using-control-surfaces/01_controlling-ardour-with-osc/02_feedback-in-osc.html

---
layout: default
title: OSC Feedback With Ardour
---                        
  
<p>
  Feedback from the Ardour to the the control surface is very useful for
  a number of things. Motor faders need to know where the the track
  they have been attached to is at before they were assigned otherwise
  they will jump to where the local fader is. Likewise, the buttons on
  each strip need to know what there value is so they can light there LED
  correctly. Transport controls should let you know if they are active
  too. This is what feedback is all about.
</p>
<p>
  Ardour does feedback by sending the same path back that is used to
  control the same function. As such any controls that have feedback
  have a parameter that is the value of the control or it's state
  (on or off). In the case of OSC paths listed on the main OSC page
  as having no parameter, if they have feedback, they will also work
  with a 1 for button press and 0 for button release. This is because
  many OSC controllers will only use exactly the same path for feedback
  as for control. For example:
</p>

<dl class="bindings">
  <dt><kbd class="osc">/transport_stop</kbd></dt>
  <dd></dd>
</dl>
<p>can be used also in the form:</p>

<dl class="bindings">
  <dt><kbd class="osc">/transport_stop <em>press</em></kbd></dt>
  <dd>where <em>press</em> is an int/bool indicating if the button is pressed or not.</dd>
</dl>

<p>
  The feedback does not have the same meaning as the control message.
  Rather, the feedback will be:
</p>

<dl class="bindings">
  <dt><kbd class="osc">/transport_stop <em>state</em></kbd></dt>
  <dd>where <em>state</em> is an int/bool indicating if the transport is stopped or not.</dd>
</dl>

<h2>List of OSC feedback messages</h2>

<h3>Transport Control</h3>
<dl class="bindings">
  <dt><kbd class="osc">/transport_stop <em>state</em></kbd></dt>
  <dd></dd>
  <dt><kbd class="osc">/transport_play <em>state</em></kbd></dt>
  <dd></dd>
  <dt><kbd class="osc">/ffwd <em>state</em></kbd></dt>
  <dd></dd>
  <dt><kbd class="osc">/rewind <em>state</em></kbd></dt>
  <dd></dd>
  <!--dt><kbd class="osc">/loop_toggle</kbd></dt>
  <dd></dd-->
</dl>


<h3>Recording control</h3>
<dl class="bindings">
  <!--dt><kbd class="osc">/toggle_punch_in</kbd></dt>
  <dd></dd>
  <dt><kbd class="osc">/toggle_punch_out</kbd></dt>
  <dd></dd-->
  <dt><kbd class="osc">/rec_enable_toggle <em>state</em></kbd></dt>
  <dd></dd>
</dl>

<h3>Master and monitor strips</h3>
<p>
  Master and monitor strips are similar to track strips but do not use
  the SSID. Rather they use their name as part of the path:
</p>
<dl class="bindings">
  <dt><kbd class="osc">/master/gain <em>dB</em></kbd></dt>
  <dd>where <em>dB</em> is a float ranging from -193 to +6 representing the actual gain of master in dB</dd>
  <dt><kbd class="osc">/master/fader  <em>position</em></kbd></dt>
  <dd>where <em>position</em> is an int ranging from 0 to 1023 representing the fader control position</dd>
  <dt><kbd class="osc">/master/trimdB <em>dB</em></kbd></dt>
  <dd>where <em>dB</em> is a float ranging from -20 to +20 representing the actual trim for master in dB</dd>
  <dt><kbd class="osc">/master/pan_stereo_position <em>position</em></kbd></dt>
  <dd>where <em>position</em> is a float ranging from 0 to 1 representing the actual pan position for master</dd>
  <dt><kbd class="osc">/master/mute  <em>yn</em></kbd></dt>
  <dd>where <em>yn</em> is a bool/int representing the actual mute state of the Master strip</dd>
  <dt><kbd class="osc">/monitor/gain <em>dB</em></kbd></dt>
  <dd>where <em>dB</em> is a float ranging from -193 to 6 representing the actual gain of monitor in dB</dd>
  <dt><kbd class="osc">/monitor/fader  <em>position</em></kbd></dt>
  <dd>where <em>position</em> is an int ranging from 0 to 1023 representing the fader control position</dd>
</dl>

<h3>Track specific operations</h3>
<p>
  For each of the following, <em>ssid</em> is the surface strip ID for the track
</p>
<dl class="bindings">
  <dt><kbd class="osc">/strip/name <em>ssid</em> <em>track_name</em></kbd></dt>
  <dd>where <em>track_name</em> is a string representing the name of the track 
  (note there is no coresponding command to set the track name)</dd>
  <dt><kbd class="osc">/strip/mute <em>ssid</em> <em>mute_st</em></kbd></dt>
  <dd>where <em>mute_st</em> is a bool/int representing the actual mute state of the track</dd>
  <dt><kbd class="osc">/strip/solo <em>ssid</em> <em>solo_st</em></kbd></dt>
  <dd>where <em>solo_st</em> is a bool/int representing the actual solo state of the track</dd>
  <dt><kbd class="osc">/strip/recenable <em>ssid</em> <em>rec_st</em></kbd></dt>
  <dd>where <em>rec_st</em> is a bool/int representing the actual rec state of the track</dd>
  <dt><kbd class="osc">/strip/gain <em>ssid</em> <em>gain</em></kbd></dt>
  <dd>where <em>gain</em> is a float ranging from -193 to 6 representing the actual gain of the track in dB.</dd>
  <dt><kbd class="osc">/strip/fader <em>ssid</em>  <em>position</em></kbd></dt>
  <dd>where <em>position</em> is an int ranging from 0 to 1023 representing the actual gain of the track in dB.</dd>
  <dt><kbd class="osc">/strip/trimdB <em>ssid</em>  <em>trim_db</em></kbd></dt>
  <dd>where <em>trim_db</em> is a float ranging from -20 to 20 representing the actual trim of the track in dB.</dd>
  <dt><kbd class="osc">/strip/pan_stereo_position <em>ssid</em> <em>position</em></kbd></dt>
  <dd>where <em>position</em> is a float ranging from 0 to 1 representing the actual pan position of the track</dd>
</dl>

<h3>Menu actions</h3>
<p>
  Every single menu item in Ardour's GUI is accessible via OSC. However,
  there is no provision for returning the state of anything set this way.
  This is not a bad thing as most menu items either do not have an on/off
  state or that state is quite visible. Binding that affect other parameters
  that OSC does track will show on those OSC controls. Examples of this
  might be track record enable for tracks 1 to 32, play or stop.
</p>