[linux-audio-dev] Re: MIDI over WiFi

On Mar 31, 2007, at 5:26 AM, Jens M Andreasen wrote: If you access to two OS X machines for a few minutes, run the Network MIDI Driver over Airport (Network MIDI Driver described here: http://www.soundonsound.com/sos/jul05/articles/tiger.htm#3 You'll see it works OK, even with the 1-2% packet loss that the IP layer sees on a typical WiFi network. Apple's implementation uses IETF RFC 4695 (a.k.a. RTP MIDI) as the transport layer, which includes a resiliency system (the recovery journal) for handling an arbitrary number of lost packets with only transient artifacts. More on RTP MIDI here: http://www.cs.berkeley.edu/~lazzaro/rtpmidi/index.html Note that there are actually third-party products now compatible with Apple's protocol, although these products are for wired networks. And, last time I checked didn't implement the recovery journal part of the RTP MIDI (and so can't be trusted over switches that lose packets -- although my info on the product might be out of date): http://www.kiss-box.com/products.pdf I haven't looked into the issue in detail, but for my own use wireless only makes sense if I don't have to be constantly worrying about the battery life of the device. At the moment, what I see in the state of the art in portable WiFi chips -- the chip in the Sony PSP and the chip in the Microsoft Zune -- is not too encouraging in this regard. But hopefully in a few generations of chip designs this will get better. This review: http://emusician.com/midi/emusic_maudio_midair/ make the point well of how limiting the battery life can be for a MIDI wireless controller right now. --- John Lazzaro http://www.cs.berkeley.edu/~lazzaro lazzaro [at] cs [dot] berkeley [dot] edu ---