The Remote Control of the Future: OSC
Shared By John Flores
Open Sound Control is a communication protocol among computers and multimedia devices which enables you to control them remotely. OSC is often an intermediary protocol sending messages to other devices on the same network which can interface with specific hardware.
We've been totally digging Open Sound Control lately.
Originally developed by the UC Berkeley Center for New Music and Audio Technology (CNMAT), OSC introduced a robust communications method to remotely control media and other digital processes. OSC is built on the User Datagram Protocol (UDP), which uses “connectionless communication" as a way to transmit information. By sending data as its own unit, each data unit is identified and routed based on the information contained within each unit. This is different from "connection-oriented communication", which relies on a predetermined fixed data channel. This means that applications can send data using UDP to other hosts on an IP network without prior set-up of specific channels or paths, making OSC inherently networkable and so very easy to use via local networks and the Internet.
OSC vs. MIDI
We are now using OSC on projects where, in the past, we would have used MIDI. OSC is infinitely granular and bundled UDP messages occur simultaneously, continuously, and nonstop; where MIDI is limited to steps and divisions because it supports a very limited range of values. With OSC you can transmit multiple data types like 32-bit integers, floating point numbers, strings and more; while MIDI only transmits 1-byte integers 0-255. MIDI uses a compact binary message format with a limited number of fields. OSC uses a human readable, URL-style address format and can send data in forms of words or numbers. OSC also includes a picosecond-resolution timestamp while the MIDI beat-clock is low-resolution with a precision of about 20,833 microseconds. To boot, the OSC data rate is Gigabit speed while the MIDI data rate is only around 31,250 bits per second!
We've successfully utilized OSC in many of our projects. We use OSC with a variety of compatible applications such as Lemur, Unity, and Resolume. Recently, we used OSC at the Hollywood Film Awards, the American Music Awards, and the American Country Countdown Awards. Utilizing OSC via Touch Designer, we were able to send commands from a mobile tablet to remotely display clips, and to trigger animations and transitions based on pre-set show cues. We've used OSC at a number of other events to remotely control dynamic installations, change parameters for different visual displays and filters in real-time, and to control intelligent lighting, all with amazingly quick and precise results.