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Notes moved when loop recording MIDI

Image icon qtr_loop_record.png80.88 KB


I have a drum track (using Calf Fluidsynth and a GM set).

I recorded the hihats. The pattern is 4 bars.

Then I record enabled the clip to do a MIDI "merge recording".

I set playback to loop, prime Record and press play.

I listen to the first 2 bars to get the tempo, then start playing the bass drum och snare using a connected MIDI keyboard on bars 3 and 4.

When the clip loops the newly recorded drum hits appear on bar 1 and 2! (When I really want to record on these two bars next.)

I stop the recording, and find the newly recorded hits on bar 1 and 2, like they are shiftet from bars 3 and 4.

Is there a setting to fix this, ie not letting qtractor shift anything? Or is my workflow wrong?



rncbc's picture

hi, maybe you've found a bug ;)

though, what do you mean exactly with "merge recording"? what steps do you take to get into there? afaics. there's no such thing in qtractor... new recorded clips will overlap existing ones so that you may yes merge them afterwards... Or is it about the special MIDI clip "overdub" mode that you may set on menu Clip > Record ?

eagerly awaiting for your clarification and feedback :)

thanks && cheers

Yes, I mean that Clip "overdub" mode (read about it on a YouTube comment from you :) ). Do you want the song file to test?

rncbc's picture

ok. now we're in same page :) no need for the song file... at least for now.

just try again and again as much you possibly can and try to find some pattern or something... try to start record/play on several locations within the loop, count the loop cycles, anything else that sounds reasonable to find the culprit...

does it move on all "overdubbed" notes? does it move only after a certain time or cycle? does it happen all the time and place?

i've tested again and again and can't get to reproduce anything strange here: all "overdubbed" notes must stay put in the precise location the play-head is, no matter how and where recording started or on which loop turnaround it is rolling at the moment--of course that's the correct behavior. moving notes around is a bug and a nasty one i'm afraid.

still waiting for s'more feedback.

thanks again.

OK, so I opened a new song and tested different variants on Clip > Record and looping and recording and all works fine.

Returned to my original file and noticed that the midi clip was offset (by 4/time units, ie 2 bars). I don't know how it got offset (and does it mean how much the MIDI data in the clip is moved relative to the start of the clip?), I didn't touch it! :) And if you look at the originl image (can't attach a new one in this comment), MIDI data starts at 0 in the drum track. But maybe this is in the clip, not the MIDI data/file?

So i opened the clip in the piano roll, set offset to 0, moved the MIDI data back into the right place (as it shifted when I changed offset). And now CLip > Record works just fine!



BTW Moving from Reason on Windows (my last reasons to use Windows) to QTractor on Debian, and it is a lot of fun, but I have to find a new workflow, and shift my own paradigms about how I work. This "connection" between MIDI clips and MIDI files is new to me. DS

rncbc's picture

spot on! you found the culprit!

ouch! overdub recording on clips that have an offset is the issue! as far as i can see, the notes get moved back or displaced in the same amount as the offset length.

fyi. clip offsets are of course fundamental and generic in qtractor timeline non-destructive editing model and they may kick in on several occasions: the most obvious one maybe when you cut or resize the beginning or the left edge of a clip.

unfortunately there's no current option setting to fix this bugger at the moment but in the source; it is probably one example of an overlooked day-zero bug i'm sure :)

so, to workaround, make sure you only overdub on uncut, pristine (offset=0) clips for the time being.

many thanks again,
for all the patience and for all the time that has been lost on this bummer; changing workflows is quite often far from easy, simple or painless, i'm sure of that ;).

[UPDATE:] good news: maybe fixed on git head master (qtractor >=

I can confirm it is working now with the latest code -- tested with Clip > Record on offset clips.

Thank you!

Great! I will compile and test it!

Well, changing workflow once in a while is (for me) often a very creative process, so I am in more ways than one very happy for qtractor in particular and Linux Audio in general. Like now, when I, thanks to your replies, truly understand what you mean by non-destructive MIDI (keeping the recorded MIDI-files, working with clips). It makes sense and will be very useful.

I think qtractor (and qjackctl) is an amazing combo, as are the Vee One synths. Yesterday I made some choirs with padthv1. Awesome plugin. Many thanks Rui!

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