I remember some time ago complaining about the jitter in Pd's output timing and someone, maybe Miller, indicated a change I could do to the source to improve the timing, I'm guessing it wasn't something that ever got merged into the source. I forget what it was though.
Hi, you can reduce the jitter editing s_midi.c, changing:
if (midi_outqueue[midi_outtail].q_time <= midirealtime)
to
if (1)
and
if (midi_inqueue[midi_intail].q_time <= logicaltime)
to
if (1)
it works for midi note and ctl, so I think it will works even with MTC