Open Sound Control (OSC) is a protocol for communication among programs, computers, and hardware, like synthesizers or multimedia devices, via networking protocols such as UDP or TCP. It can be thought of as a replacement for the MIDI protocol with rich benefits, like supporting symbolic and high-resolution numerical argument data, providing an URL-style naming scheme in combination with a pattern matching language, and allowing to bundle messages for a better handling of timing and simultaneous processing.
Hydrogen is able to receive and send OSC messages. This allows you to control it using various devices, like hardware OSC controllers, smartphones, tablets, or any PC. For Linux-based systems you can use or test these interactions using the command line program oscsend.
$oscsend localhost 9000 /Hydrogen/NEW_SONG s /tmp/new.h2song
To enable OSC support in Hydrogen, open the OSC tab in the Preferences dialog. Make sure that the "Enable OSC support" checkbox is activated, otherwise Hydrogen will not listen for incoming OSC messages.
Hydrogen's port number defaults to
oscsend should only be used for sparse interactive testing and control via a command-line. Using it in scripts is not recommended since every time it sends a command it will registers a new client at the OSC server. If the Enable OSC feedback option in the OSC tab of the Preferences dialog is checked, Hydrogen will send its current state to all registered clients causing it to become slower and slower with every oscsend command sent. Soon you will experience visual lags. When unchecking this option, however, using oscsend is fine.