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Qtractor : routing problem

Hello everyone,
I have a problem with routing QTractor ... My goal is to use the mixer QTractor as a "digital" mixer ,
coupled with a sound card.
Here is the routing, defective, simplified to the extreme :

input1 bus, with input / output
return1 bus with input / output
return-master bus with input / output .

The signal enter in the input1 bus. The signal is routed via insertion / auxiliary input on return1 activated , gain 1.
Here, the signal is visible on the meter of return1 - out. Everything is fine.

I then redirect the signal via return1 - out "output" , on return-master in.
And here, there is no signal on the input of return-master , and I do not understand ...

With a diagram, it looks like this :
The input signal ---> in input1 (ok)--> aux send return1 (ok) --> return1 output (ok)---> return-master input --> (not ok, no signal !)


Thank you to the Qtractors experts !

rncbc's picture


this is a known and rather old problem of qtractor and jack clients in general: connecting outputs to own inputs do seldom work at all for single jack client instances and qtractor always runs as a single jack client.

all this has been reported and discussed to death many times and years before and things just don't, won't get magically solved anyway.

again, qtractor does run as a single jack client and thus it will incidentally suffer from so called jack's "zero-copy optimization" on port buffers. sometimes it works (signal appears on input), some other times and cases do not (just silence)--it's all deeply dependent on internal process flow and (re)creation order--so, for instance, you may get it working for a while on an initial editing and then it just stops working after you (re)open the session some time later (and/or vice-versa).

in general, it is NOT advisable to connect any jack-client--and qtractor in particular--outputs directly into any of its own inputs.

however, note the "directly" saying above, if you resort to insert one other simple jack-client in between, things will start working though with additional period of latency. or, in some other cases, by connecting at least one additional source to the intended input things might work as well.

alas. you're not doing anything wrong, i must say. it's just that you were assuming it could on intuition, but unfortunately there's a reason why it doesn't. sorry.


thanks for the reply !

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