Open Sound Control ROS

This repository contains several packages for ROS 2 Jazzy intended to interact with Open Sound Control.

What is Open Sound Control?

Open Sound Control (OSC) is an open-source data transport specification for realtime communication between applications and hardware. Similar to MIDI, OSC is indended for use with electronic musical instruments primarily, but can have other applications.

OSC, by default, uses UDP packets to transmit encoded data from one application to another. Each packet consists of an address (similar in principle to a ROS topic) and one or more variables of specific types.

For details on the OSC 1.0 and 1.1 specifications, see the official documentation at the links below:

• 1.0 specification
• 1.1 specification

OSC to/from ROS

The open_sound_control_msgs package contains the ROS message definitions needed for handling OSC packets in ROS.

The open_sound_control_bridge package contains a ROS node that will accept OSC messages and translate them into the corresponding ROS messages, or accept ROS messages and translate them into their corresponding OSC messages.

The open_sound_control_bridge node publishes all received OSC messages as open_sound_control_msgs/msg/OscMessage messages on its osc_raw topic. Additionally, the brige node will publish each individual variable inside the OSC payload on an individual ROS topic whose name corresponds to the OSC address followed by the type and a numbered suffix.

For example, this OSC message

  2f (/)  66 (f)  6f (o)  6f (o)

  00 ()   00 ()   00 ()   00 ()

  2c (,)  69 (i)  69 (i)  73 (s)

  66 (f)  66 (f)  00 ()   00 ()

  00 ()   00 ()   03 ()   e8 (è)

  ff (ÿ)  ff (ÿ)  ff (ÿ)  ff (ÿ)

  68 (h)  65 (e)  6c (l)  6c (l)

  6f (o)  00 ()   00 ()   00 ()

  3f (?)  9d ()   f3 (ó)  b6 (¶)

  40 (@)  b5 (µ)  b2 (”)  2d (-)

containing the address /foo, the integer -1, the string hello, the float 1.234, and the float 5.678 would be republished as the following topics:

• osc_raw: open_sound_control_msgs/msg/OscMessage – the raw OSC data re-encoded as a ROS message
• /foo/int_0: std_msgs/msg/Integer containing the value -1
• /foo/str_0: std_msgs/msg/String containing the value hello
• /foo/float_0: std_msgs/msg/Float32 containing the value 1.234
• /foo/float_1: std_msgs/msg/Float32 containing the value 5.678

The following table shows the OSC types, the ROS topic name, and ROS message type:

where _N is a 0-based index indicating the relative order of variables of that type.

To configure ROS -> OSC conversions, the bridge node must be properly configured. See bridge configuration, below.

OSC address and ROS topic naming standards

OSC does not strictly enforce many standards on the address. ROS topic namespaces on the other hand follow stricter conventions:

• topic names may only contain lower-case letters, numbers, and underscore (_) characters
• no portion of the namespace may have a leading integer
• leading _ characters cause the ROS topic to become hidden

When generating the ROS topic name from the OSC address, the following modifications will

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