[LAU] what's up with midi clock

Atte André Jensen atte.jensen at gmail.com
Fri May 29 13:50:29 EDT 2009


Hi

Long story short: I'm writing a osc2midi_clock script in chuck for 
controlling sooperlooper from incomming osc messages. I have no 
experience with midi clock so I had to play around with it. The 
following seems to work (T for time messges (0xf8), S for start (0xfa), 
x23 means "repeat 23 times"):

S  Tx23 S Tx23 S etc.

It even works to the point that I can throw in clients at any time, 
since the start messages resets the clock every quarter note. The two 
clients I checked with are sooperlooper and renoise.

*However* the specifications I looked at are:
http://www.harmony-central.com/MIDI/Doc/table4.html
http://www.blitter.com/~russtopia/MIDI/~jglatt/tech/midispec/seq.htm

They both suggests that it should actually be

S  Tx24 S Tx24 S etc, with little or no time between S and the following T.

However here the clients (again sooperlooper and renoise) doesn't show 
the test tempo 112 but somewhere between 116 and 117.

Anyone has any idea what the right way?

Also; I've been discussing this with Jesse Chappell (author of 
sooperlooper) and he says that he looked at his code and thinks there's 
a bug (which makes it work correctly with my wrong midi clock, since 
that's actually written targetting sooperlooper). Now it would be very 
interresting to look at other clients and masters of midi clock, however 
not having worked with midi clock before, what would be the first 
clients to cross check with?

-- 
Atte

http://atte.dk   http://modlys.dk   http://virb.com/atte



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