[ubuntu-studio-users] Tempo changes in qTractor

Ralf Mardorf ralf.mardorf at alice-dsl.net
Thu Sep 15 09:19:09 UTC 2016

Hi David,

I posted this reply to qtractor devel, too.

Hi qtractor devel subscribers, hi Rui,

there's a thread at Ubuntu Studio users,
and I'm unable to help anymore.

On Thu, 15 Sep 2016 09:03:41 +0100, David Sumbler wrote:
>In case you're wondering why the midi beats are irrelevant, what I have
>done (and want to do with quite a lot of other music) is to enter
>tracks from a midi keyboard, with all the subtleties of timing that a
>live performance can have and should have for certain types of music.
> I can then tweak details.  The actual "beats" in the midi file are
>irrelevant except as a means of controlling the timing of the output -
>the actual notes will only be approximately with those beats, or
>perhaps not at all.

What you are doing is the same as just not quantising, since changing
from bars to time doesn't improve the MIDI resolution. This is done by
increasing the ticks per quarter note. I don't know if Qtractor allows
to change the value for ticks-per-quarter-note, but it anyway most
likely would be unimportant, since nearly all PCs suffer from that
much MIDI jitter, that even an Atari ST and even a C64 with less
ticks-per-quarter-note are closer to what you played, due to quasi zero
MIDI jitter. Regarding the tempo changes it will be inaudible, if it
starts a few ticks before or after the note on event, while the exact
position of the note on event, indeed is important, but unfortunately
getting rid of MIDI jitter is impossible with many PCs.

IOW simply keep bars and just don't quantise. There shouldn't be a
difference to choosing time instead of beats. Again, to get a higher
resolution you would need to increase the ticks and when doing this,
you shouldn't expect that your PC has that good hard-real-time for
MIDI, that the jitter doesn't affect your recorded playing.

However, as already pointed out earlier, better send a request to the
coder at the qtractor mailing list. I already provided the link earlier
in this thread.


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