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Syncronisation via Midi Clock works just fine

Dear Rui Nuno Capela,

the sync feature (Midi Clock) of qtractor 0.4.7 works very fine on my system. Thank you very much for sharing qtractor with me/us!

Greetings from Austria,

rncbc's picture

I should make it clear that Qtractor listens to MIDI clock just to set its current session tempo (BPM). That and SPP (Song Position Pointer) might be the couple which makes it sync altogether (no quite sync'ing, but beat matching, sort of)

Cheers && Thanks

Does MIDI Clock also work with MIDI out?

Can qtractor send MIDI Clock to work as master?

rncbc's picture

well, answer to that was implicit right on the OP.

just check whether View/Options..../MIDI/Playback/Clock is set to "Output" or "Duplex" (the later will make it also behave as slave).


Hi Rui, Does Qtractor time lock to Midi Clock ? as I can't seem to get it to lock onto my Alesis SR16 midi clock out. It does see Midi Start but after that it seems to free wheel with no sync.

Oh, I am running the Alesis SR16 as master via m-audio interface into QjackCtl 0.5.0 routed to Qtractor 0.9.5 with "Midi Control" set to Duplex or Input.

rncbc's picture

strictly speaking, qtractor dos not sync/*lock* to MIDI Clock...
as said quite earlier in this topic, it just and only reads the tempo (BPM) from it and sets it accordingly to the current tempo map location bar (usually the main session BPM).


ps. qtractor v0.9.5 is ugly old and decommissioned :) as is also the case for qjackctl v0.5.0. please consider a major update to both accounts. byee

Hi Rui, Firstly I am a big fan of your work :-) I moved 30 songs from Tascam Reel to Reel into Ardour. When synchronising Ardour 6.5 (master) to Qtractor 0.9.20 (slave) via "midi clock" (as the tape speed drifted over time), Qtractor progressively looses sync with Ardour. By approx 3 minutes into the song Qtractor jumps bar/clock position and runs at half tempo. Setting both Qtractor and Ardour to show samples/frames and Ardour sending MMC. Stopping Ardour, and moving Ardour's playhead (cursor) to any bar around the 3 minute mark shows a difference in sample position of approx 400+ samples between the two DAWs. Is there a better way to sync the two packages. I am willing to help with coding if needed :-)

rncbc's picture

hi, thanks

as said before, please remember that qtractor won't exactly sync to incoming MIDI clock whatsoever: it just reads the tempo (BPM) from it and sets it as current tempo.

if MMC is in use for ardour -> qtractor communication, which is not a sync protocol either, please check in qtractor's messages window for receiving MMC events... check if there are any MMC Locate event: as the MMC location is allegedly specified in SMPTE format (hh::mm:ss.ff) with frames (ff) ranging from 0 to 29 or 30, there is the the real possibility to err in 48000/29=1600 frames at most and in the worst case (and assuming 48000 is the sample-rate in charge).

in conclusion: don't ever trust MIDI clock or MMC to pursue any sample accurate syncing, because the former won't do it at all and the later will do it quite badly.

the best you may have in this regard to qtractor is probably JACK Transport.


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