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jack transport problem
Hello, I have some problems using hydrogen and qtractor synced with jack transport. Of course initially I thought it was a hydrogen problem ;) but with rosegarden replacing qtractor it seems to work ok (not with hydrogen set as master, but that AFAIK has allways been buggy with hydrogen) ...
basically when the song starts from the beggining everything is ok, but as soon as I move the playhead around in qtractor (manually or when it hits a loop range) the playhead in hydrogen jumps to somewhere else. Only way to resync them is to bring the playhead back at the beginning of the song.
I'm I the only one with this issue? I found a mail on LAU of Rosea from about a year ago where he was having similar issues, and Rui you said that it could well be a qtractor problem... so this is known?
BTW this was tested with qtractor svn revision 1711 and hydrogen 0.9.5
cheers
renato
re. jack transport problem
well, a year ago, iirc. qtractor and hydrogen were more finicky re. jack transport positioning--not anymore, at least on the qtractor side :)
anyway i've just tested with hydrogen 0.9.6svn trunk and it doesn't show any of the behavior you're reporting.
care to try again or please explain in more detail what seems to be the problem?
which of the programs (qtractor, hydrogen or even qjackctl if you happen to be running it too) shows a wrong transport position (time) ? from the above report it seems it's hydrogen but i repeat i could not reproduce the issue with the latest svn trunk.
cheers
well, yes, it seems a
well, yes, it seems a hydrogen problem - just checked out hydrogen svn and problem persists.
both qtractor's playhead and qjackctl's bar number behave as expected. I noticed now that it suffices to pause and resume playback (either in h2o, qtractor or qjackctl) to have the playhead in hydrogen jump around, i.e. when I resume playback about 50% of the times the playhead jumps somewhere else in the track and plays from there.
so I'll be reporting it to hydrogen devs...
EDIT: link to post on h2o forums
thanks
renato
so the problem was that it
so the problem was that it seems it's ATM not possible to have say a tempo of 4/4 set in qtractor and patterns of length other than 8 in hydrogen... I had a 4/4 tempo in qtractor and patterns of lenght 16 in h2o, and changing the tempo to 8/4 in qtractor seems to solve the issues I was having.
You may be interested in the explanation Wolke gave me of the reasons behind this behaviour - here
cheers
renato
re. so the problem was ...
i've read the explanations and i don't buy them :)
jack transport absolute position is primarily expressed in frames, not in musical metrics (bar.beat.tick aka. bbt).
hydrogen should read and convert that position (in frames) to its own metrics (in bbt) even though qtractor does supply its own conversion as a transport master. iow. hydrogen shouldn't rely on the bbt information supplied by qtractor when it has a song metric (beats per bar) and/or resolution (ticks per beat aka. ppqn) of its own.
i guess that's the root of the problem: in general, all sequencers participating in a jack transport session should agree to follow the tempo, bbt position and resolution of the master. otherwise they should just follow absolute transport frame position, no less.
hth.
cheers
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