[sdiy] Bunching of MIDI clock messages
21pointy at tpg.com.au
Wed Sep 11 14:04:32 CEST 2013
David from Innerclock has looked at this extensively, at least
empirically, in his quest to improve timing accuracy between computer
DAWs and hardware instruments.
for some real world numbers
On 11/09/2013, at 9:32 PM, rburnett at richieburnett.co.uk wrote:
> How common is "bunching up" of MIDI clock messages due to erratic
> transmission out of sequencers?
> For example, if I check for the reception of a MIDI clock message
> every 2 millisconds in a receiving instrument is that sufficient?
> (In theory 2ms polling rate should be sufficient to support tempo up
> to 1250 BPM provided the clock events arrive with even spacing!) Or
> do you think I should cater for the possibility of receiving as many
> as seven MIDI clock events transmitted "nut to butt" over my 2
> millisecond polling period!?!?
> I know the MIDI specifications says that MIDI clock messages are to
> be transmitted with even spacing at the average tempo rate, but I
> don't think i've ever seen a maximum jitter specification anywhere?
> (I can just imagine sequencer software getting preempted in a
> Windows environment, and later transmitting all of the overdue MIDI
> data in an intense burst.)
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