OSC - Open Sound Control Protocol

Even if you only own one piece of music hardware, there's a very good chance it's equipped with MIDI. The connection protocol has become so ubiquitous that it's almost impossible to find new synths, controllers or even software that don't support it. However, the skeptics would have us believe that Its days are numbered thanks to new protocols arriving on the market.

While such alarmist attitudes are probably unfounded, it seems that there's an increasing demand of something slightly more advanced the long-established industry standard. In this article we are looking at Open Sound Control (OSC), one of the protocols vying to steal MIDI's crown. We'll see what it's all about and why you might expect to hear a lot more over the next few years.

osc software

The downsides of MIDI


A discussion of OSC is practically impossible without first understanding why MIDI might not be up to the job for today's electronic musicians. The MIDI protocol which has become an industry standard for transmitting note data, timing signals and controller information between Electronic music hardware and software. It contains no sound signals whatsoever, just the information required to allow pieces of equipment or software to generate and process sounds. For most everyday purposes, MIDI does a perfectly satisfactory job- it's no surprise that it's been a mainstay of hardware manufacturers and musicians since its arrival in the early 80s. We almost all use it to control synths, get note information into our plug-ins or store patterns in our DAWs and sequencers. However, it's quite possible that you've already run into some of the protocol's limitations if you've tried to do anything more advanced.

The problems mainly stem from the fact that MIDI employs what has now become a slightly outdated approach to data transmission. In the MIDI protocol, messages are sent in real-time down a serial connection and processed the instant they're received by a device. MIDI's 31,250 baud rate (the number of pulses per second in the digital signal) equates to roughly 1,300 messages per second along a given MIDI cable (which may be carrying signals on up to 16 different channels simultaneously). If we quickly move a MIDI control from its minimum to rnaxirnurn, we generate 127 messages in the space of a fraction of a second. Automate two or three parameters simultaneously and we soon start to approach the limits of the bandwidth.

An inherent problem here is that no two messages can be sent synchronously (at precisely the same time), so attempting to send high volumes of messages down a MIDI cable results in timing imprecision. As a result, tile more information we attempt to send down a MIDI cable, the less accurate the timing becomes. If you've ever tried to daisy-chain several MIDI devices on the same output from your interface, you've probably experienced the sloppy timing that can arise from it.

A further weakness of the protocol is that the MIDI specification limits the amount of data to be transmitted by allowing just 128 values (0-127) for parameters such as velocity, note value, pitch bend, modulation and so on. Send a MIDI controller value to a synth's filler cutoff frequency or oscillator pitch, gradually adjust the setting and you'll soon hear a digital stepping sound (often referred to as a 'zipper effect') as the controller moves from one discrete value to the next rather than sliding smoothly from one point to another.

Technological advancements


It should go without saying that electronic technology has advanced almost immeasurably in the three decades since MIDI was first developed. High bandwidth data interfaces are now commonplace - everything from USB and FireWire to home wireless networks and broadband internet connections. As a result, the potential for a high bandwidth musical instrument protocol is far greater than it was back in the early '80s. At one point in the mid-1990s, all eyes were on the ZIPI (Zeta Instrument Processor Interface) protocol to replace MIDI altogether, but the technology was never widely adopted despite its improved bandwidth and apparent benefits over the older standard. For the foreseeable future, rumors of MIDI's demise are greatly exaggerated. Plenty of us still use apparently obsolete technology such as CV/gate and DIN sync to control our vintage hardware, so the chances of the music world immediately ditching MIDI for a newer standard seem slim at best. Instead, it seems that there's an increasing demand for a control protocol that can co-exist with MIDI, offering more powerful and flexible options where they're needed but not necessarily attempting to replace the old standard.

While it's always difficult to predict the Mure of music technology, the most likely contender seems to be Open Sound Control (OSC), a protocol developed (like ZIPI) by researchers at the University of California, Berkeley's Center for New Music and Audio Technologies (CNMAT).

What is OSC?


The Open Sound Control protocol was first developed in the mid-1990s and a full specification was published in 1997, but the majority of Widespread Interest m OSC has emerged in the last four or five years. Rather than being a rigidly defined transmission format like the original MIDI protocol, OSC messages can be sent over a variety of interfaces. OSC transmits data in packets, a standard approach to networking widely used in local area networks and internet connections. As such, the technology primarily lends itself to connection via local Ethernet and WiFi networks. In the case of OSC, each packet contains either a single message or a bundle of messages, each of which includes an address pattern (the details of where it's being sent), a type tag string (a description of what the message is) and an argument (the data contained In the message, such as a parameter value).

Perhaps the crucial difference between MIDI and OSC is that OSC allows a lot more information to be sent between devices. Not only can arguments contain floating point values (as opposed to MIDI's 128 discrete values), but the higher bandwidth means that there's a much higher limit to the number of messages the connection can handle. Whereas MIDI messages are sent in real-time and executed as soon as they're received, OSC packets include time tags that define when the arguments they contain should be implemented. As such, the protocol's timing is inherently far more precise and stable than MIDI.

Most importantly, though, OSC is simply much more versatile and flexible than MIDI. Networks can be expanded via widely available, cheap Ethernet switches rather than expensive multi-port MIDI Interfaces and developers can implement a variety of different control parameters depending on the needs of a given piece of hardware or software. The protocol can be implemented into existing hardware and run alongside MIDI devices without any compatibility issues. OSC doesn't necessarily need to replace MIDI altogether - it you've got MIDI devices which work perfectly then there's no need to worry about them becoming obsolete just yet - but manufacturers are becoming increasingly aware of the advantages it can offer.

Practical applications


It would be misleading to suggest that OSC has been widely adopted at this stage, but a handful of high-profile products have started to bring the technology into the mainstream. Most notably, hardware controllers such as the JazzMutant Lemur and the Monome range, released in 2007 and 2008 respectively, adopted the protocol for transmitting data. Software support is slightly less widespread for the time being, although OSC has been adopted by Native Instruments (for their Traktor OJ package and Reaktor modular synth software) and is supported by a vanety of less mainstream music applications such as Plogue Bidule, SuperCollider and MaX/MSP. Even if your software or hardware doesn't currently support OSC, utilities such as OSCulatorPure Data and MIDI Yoke allow OSC to be integrated neatly with just about any existing setup. It should come as absolutely no surprise if plenty more developers and manufacturers start to adopt OSC over the next few years.

Ignore the hype about the death of MIDI - the industry standard is here to stay for the foreseeable future. But the Open Sound Control protocol seems likely to be very important in the next few years. as hardware and software manufacturers look to take advantage of its accurate, versatile and powerful features. OSC is already gaining ground in commercial products, rather than being restricted to the more esoteric programming environments like MaX/MSP and SuperCollider. The great news is that it's unlikely to make your existing equipment obsolete - your music computer probably already has Ethernet ports and/or WiFi, so integrating OSC hardware shouldn't be a problem. The advantages of the protocol are clear, now it's time tor manufacturers to step up and adopt it.