Qtractor - plugins that combine audio and midi

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thebutant
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Qtractor - plugins that combine audio and midi

Postby thebutant » Tue Sep 11, 2018 8:50 am

Some plugins have an audio input and a midi input, for instance Zita-AT1.
You can play the autotuned audio with a midi keyboard.
But is there a way of using this in Qtractor?

When set on an audio track, I don't know how to connect midi to it. When set on a midi track, there is no audio to play.

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rncbc
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Re: Qtractor - plugins that combine audio and midi

Postby rncbc » Wed Sep 12, 2018 6:30 pm

on qtractor, you can only do both audio and MIDI on a MIDI track.

audio tracks can only do audio pcm and that's final.

however, MIDI tracks are hybrid, if you prefer to call that way; MIDI tracks may convey both MIDI _and_ audio pcm in its plugin chain;

for instance, you can have audio (internal pseudo-plugin) inserts (aka. send/return) in a MIDI track; audio is processed ins through outs, as always;
this kind of side-chaining is possible and take care that is sorts of an external loop contraption (via jack-audio graph, obviously); delays (aka latency) ensues :)

take care

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Re: Qtractor - plugins that combine audio and midi

Postby thebutant » Thu Sep 13, 2018 7:54 pm

Thanks for you answer!
I wasn't aware of midi tracks' hybrid nature, so it's a good thing you pointed it out.
Still, after trying for a long time, I'm just not able to make any use of it.

When dealing with a vocoder or Zita-AT1, I have so far used an external plugin host (well, Carla), routing the vocal and the midi from Qtractor -> via the plugin (vocoder or Zita-AT1) in the external host -> the vocoded or autotuned sound back into a new track in Qtractor.

I'm not sure that you're saying there is a way of doing this inside of Qtractor. Are you? With internal inserts?
I would be delighted, as it would make the whole thing a lot easier to deal with.

But I do think you're saying it's only possible to mix audio and midi with inserts the other way around. Audio into midi plugins (in midi tracks).
But I cannot think of any plugin where this would be useful. Can you please tell me the name of one or a few, and I'd be happy to explore it! :)

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rncbc
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Re: Qtractor - plugins that combine audio and midi

Postby rncbc » Thu Sep 13, 2018 9:28 pm

look to some few vocoder and sidechaining YT tutorials out there... it's exactly what i'm saying.

byee

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Re: Qtractor - plugins that combine audio and midi

Postby bluebell » Fri Sep 14, 2018 6:00 am

thebutant wrote:Some plugins have an audio input and a midi input, for instance Zita-AT1.
You can play the autotuned audio with a midi keyboard.
But is there a way of using this in Qtractor?

When set on an audio track, I don't know how to connect midi to it. When set on a midi track, there is no audio to play.


I placed CALF Vocoder in an Audio Bus and it worked fine.

To get perfect timing especially with big buffer sizes note that both CALF Vocoder and the routing to a bus add the latency of one buffer – audible with buffer sizes of 512 and more.

So my setup in general is:

TRACKa - BUS1 - STAGINGBUS - MASTER
TRACKb - BUS1 - STAGINGBUS - MASTER
TRACKc - BUS2 - STAGINGBUS - MASTER

No track goes directly to MASTER or to STAGINGBUS to ensure the same processing latency.

CALF Vocoder adds one buffer of latency so it has to be placed in a BUS that's connected to MASTER, not to STAGING.

4-Channel-BUS_WITH_CALF-Vocoder - MASTER (only output 1 and 2 of the Vocoder bus are needed)

Feed CALF Vocoder with the output of tracks or with AUX/INSERT SENDs.


If you don't use a Vocoder then I recommend a simpler layout:

REVERBBUS1 - MASTER
REVERBBUS2 - MASTER
ECHOBUS - MASTER
TRACKa - BUS1 - MASTER
TRACKb - BUS1 - MASTER
TRACKc - BUS2 - MASTER

or even

TRACKa - MASTER
TRACKb - MASTER
TRACKc - MASTER

but never ever

REVERBBUS - MASTER
TRACKa - BUS1 - MASTER
TRACKb - MASTER
TRACKc - BUS2 - MASTER

As soon as you use buses for reverb, echo and so on you should route all tracks to a bus that goes to master, not directly to master. So the effect signal has the same latency as the tracks' signal.

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Re: Qtractor - plugins that combine audio and midi

Postby thebutant » Fri Sep 14, 2018 6:50 pm

Hey again.
It was silly of me to drag vocoders into this, it just made it all confusing.
(The reason is that I've lately been fiddling with TAL vocoder, which has a built-in carrier you can choose to use.)
So forget about vocoders. 'Cause vocoding and sidechaining I can do internally in Qtractor. No problem.

What I cannot figure out is how to use audio effects with midi inputs, midi control.
Such as Zita-AT1. Plugins that when opened in Carla show up as audio clients, but which also have an "events in" midi client.
The point is that Zita-AT1 (or TAL vocoder) uses midi to control their audio input. Key control, if you like.
And I'm not able to make a connection in Qtractor that lets such a plugin process the audio, and then use midi to control this audio. Autotuning with midi, for instance. Playing the autotuned audio with a midi keyboard or make a midi track to control the tones.

If it's not possible, then it's ok. Then at least I'll stop trying. But I don't think it's the same as sidechaining, as this involves midi control of an audio plugin. At least I'm not able to do it the same way as I sidechain (or use a vocoder).

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rncbc
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Re: Qtractor - plugins that combine audio and midi

Postby rncbc » Sat Sep 15, 2018 12:16 pm

have some step-by-step instructions :)

1. on a MIDI track, add an audio insert pseudo-plugin (plugin-menu: Inserts > Audio > Add Insert) _before_ the zita-at1; the MIDI track stream will be the _control signal_ in there (you can have it in sequence of MIDI clips or you can have the (live) feed from a MIDI keyboard while on (auto-)monitor;

2. connect the desired audio signal input(s) to the audio insert *Returns* ports; that may be the outputs of an(y) audio output bus or any other (external) JACK client, not necessarily qtractor;

3. leave all the audio insert *Sends* ports dangling/open or not connected to anything; you won't need them anyway, as the "return" audio signal is the one that feeds the chained zita-at1 plugin as input;

4. the zita1-at1 processed (auto-tuned') audio signal flows out just like a normal MIDI instrument plugin output would: the audio signal is streamed to the next audio_fx plugin in chain and/or ultimately to the designated audio output bus for that plugin chain (default is "Master Out", but you can choose any other existing audio output bus or even have dedicated audio output ports; see plugin-menu "Audio > ...").

hth.
cheers

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Re: Qtractor - plugins that combine audio and midi

Postby thebutant » Sun Sep 16, 2018 8:56 am

Thank you so much!
This recipe is gold. I really appreciate it! :D

So the sad thing now is that I simply can't get any output from this method.
But then I guess my problem lies elsewhere than the method itself, because this is really pretty straightforward.
As a matter of fact audio inserts give me no sound whatsoever, whether they're put on audio or midi tracks. I can route as much sound to them as I like, they're nevertheless silent as oysters.

Well, I attach a screenshot just to show you that I've actually understood the procedure.

I'll try and research the audio insert silence a bit on my own.
Thanks again!
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rncbc
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Re: Qtractor - plugins that combine audio and midi

Postby rncbc » Sun Sep 16, 2018 10:03 am

i forget to tell you there's a catch:

in general, it is NOT advisable to connect any qtractor outputs to any of its own inputs like it's being suggested on step 2. above. qtractor runs as a single JACK client and for that matter it might suffer from the so called JACK's zero-copy optimization on same client port buffers. technically, with regard to internal qtractor processing and signal flow, this is same as short-circuit (shunt) onto a buffer that hasn't been filled in yet.

the issue issue is one kinda pretty old and the only workaround/solution that i remember for this is about having another JACK client connected between the output bus ports and the insert input ports (ie. returns); an all-pass/thru/meter/etc. JACK client in between will do.

sorry for that;
hth.
cheers

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bluebell
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Re: Qtractor - plugins that combine audio and midi

Postby bluebell » Sun Sep 16, 2018 4:57 pm

rncbc wrote:i forget to tell you there's a catch:

in general, it is NOT advisable to connect any qtractor outputs to any of its own inputs like it's being suggested on step 2. above. qtractor runs as a single JACK client and for that matter it might suffer from the so called JACK's zero-copy optimization on same client port buffers. technically, with regard to internal qtractor processing and signal flow, this is same as short-circuit (shunt) onto a buffer that hasn't been filled in yet.


It depends. Connecting a bus' outputs with master input works. Connecting a bus's output with another bus' input works here, too, if I don't create loops.

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bluebell
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Re: Qtractor - plugins that combine audio and midi

Postby bluebell » Sun Sep 16, 2018 5:31 pm

bluebell wrote:
rncbc wrote:i forget to tell you there's a catch:

in general, it is NOT advisable to connect any qtractor outputs to any of its own inputs like it's being suggested on step 2. above. qtractor runs as a single JACK client and for that matter it might suffer from the so called JACK's zero-copy optimization on same client port buffers. technically, with regard to internal qtractor processing and signal flow, this is same as short-circuit (shunt) onto a buffer that hasn't been filled in yet.


I think with "own inputs" you mean a track's or bus' own inputs.

Connecting a bus' outputs with master input works. Connecting a bus's output with another bus' input works here, too, if I don't create loops.

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Re: Qtractor - plugins that combine audio and midi

Postby thebutant » Sun Sep 16, 2018 7:33 pm

rncbc wrote:the issue issue is one kinda pretty old and the only workaround/solution that i remember for this is about having another JACK client connected between the output bus ports and the insert input ports (ie. returns); an all-pass/thru/meter/etc. JACK client in between will do.

THIS!
Then it all works really nicely. Thanks!
I really didn't know Qtractor was able to to this.
You are a gem, rnbc! As is your software.

So now the only issue left is exporting such a track. So far I get only noise, not what I'm hearing.
Better to record to Audacity than try exporting?


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