The MIDI 1.0 specification was released in 1984 in an attempt to end the Babel of proprietary interfaces that dominated the early days of electronic synthesis. This product of the MIDI Manufacturers Association (MMA), a consortium of large and small manufacturers of electronic musical gear, has been the backbone of live music performance for over 2 decades now. This is a testament to it's foresight and a clear acknowledgement of the need that it filled. Initially it specified only the basic interconnection of gear and a simple data protocol. The application layers were left to the manufacturers to define. This still made interconnection of gear from multiple manufacturers a challenge and patch and controller assignments had to be re-learned with each new piece of gear that one added to a rig. Eventually, separate application layers were defined; General MIDI and GM2, MIDI Machine Control, Standard MIDI Files, and MIDI Show control allowed true integration of equipment from multiple manufacturers to automate studios and live performance. This did not prevent proprietary extensions such as Roland's GS and Yamaha's XG extended GM sets.

MIDI's 31.25 Kbit/sec. data rate was originally set by the fact that it could be derived by a simple division of the 8048 microprocessors clock out signal and it was sufficient to support the technology of the time and all of the applications that were then conceivable. As MIDI's use has extended beyond simple keyboard control of external sound modules, The data rate and number of devices supported has become limiting. These limitations have been partially skirted by computers with multiple MIDI interfaces, and external devices like mergers and multiplexers. But the limits of MIDI are real and the standard is reaching the end of it's extensibility if not it's useful life. So where does the industry go from here.

There have been several attempts to adapt the MIDI protocol to higher speed hardware and transport protocols with the three best known being IEEE-P1639, MIDI-LAN, and IETF RTP-MIDI. RTP-MIDI by the Internet Engineering Task Force has become the front runner and has been incorporated in Mac OS-X. The Real Time Protocol is compatible with both UDP and TCP transport layers. The MIDI messages are unaltered within the RTP. And multiple MIDI streams are supported. Apple has implemented their own version of the Session Control Protocol and it has been adopted my other manufacturers and is being look at by the IETF as a possible standard. Only one company has released a windows XP implementation of RTP-MIDI for their own products, a Dutch company named Kiss-Box.

Another contender for next generation MIDI is Open Sound Control (OSC) developed by the Center for New Music and Audio Technology (CNMAT). It has been used in the Reaktor software synthesizer and other cutting edge projects but has not been adopted by any major applications and no stand alone instrument currently supports this protocol.

Yamaha has mLan based on IEEE 1394 more readily know as the fire wire standard. It supports multiple MIDI channels but is patented and proprietary to Yamaha and requires licensing for implementation by other manufacturers.

HD Protocol or HD MIDI has been in development since 2005 by the MIDI Manufacturers Association. Designed to carry multiple channels and high speed transports it is also planned to have higher granularity, ie. more than 128 levels, and allows for new message types. Various tranports are being considered including Architecture for Control Networks which is a theatrical automation standard that has widespread use in theatre. And while RTP-MIDI in the apple OS-X implementation is the current leader in next-gen MIDI applications, final release of the HD Protocol could cause this standard to leap frog the RTP-MIDI protocol as the industry standard due to the wide participation from musical equipment manufacturers of all sizes.

So the bottom line is that while MIDI continues to press the boundaries of it's current implementation several contenders are on the horizon for the next-gen MIDI standard. There is not yet a clear winner but rather two strong contenders and a handful of also-ran's. It is clear though that next-gen MIDI will support high speed transport, multiple channels, and extensibility for applications that are still yet to be conceived and could be the standard for next several decades.