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Sents are lost after reopening project
Hello,
First I want to thank you for all the work you put into qtractor. It works great except for the issues below ;)
I have an issue with qtractor when projects are [re]opened all sends (to other tracks) are lost and not recoverable.
Perhaps I do something which is not meant to be used in this way.
For reverb I try to use or create a sent/return bus. A kind of fx bus to which audio is sent for adding reverb
My routing is as follows:
1 audio track with insert and reverb plugin (name FX2)
1 normal track with (which tracks audio files) with an insert to the FX track above (name Track 1)
Insert Track 1 sents to FX2
FX2 returns to Track 1 (?)
This works. But when the project is reopened the next time, the audio doesn't stream anymore to the FX bus.
The connections in the connections window are still there. When disconnect and reconnect nothing changes.
So basically all sents are lost and have to be done from scratch.
I'm not sure this is the right way to do it in qtractor but initially it works and seems the only way to do this.
(The issue is the same on Arch linux as on Fedora (distributed version qtractor or self compiled))
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Another issue, but it's not specifically related to qtractor because Ardour has the same problem.
I'm using firewire audio (Saffire pro i/o 26) via FFado and a RT kernel. A self compiled kernel, FFado and Jack on Arch Linux and the Planet CCRMA RT kernel on Fedora. Both systems have the same behavior.
When exporting audio (or a single range edit) the Saffire shuts down and the connection gets lost. In qjackctl the cpu goes to 100%. Mostly the connection is corrupted and everything has to be restarted again. In some cases the connection is reestablished automatically (not in Ardour). In qtractor the audio get rendered, in some cases it doesn't.
It doesn't matter if there are a lot of processing fx involved or none. Even a singe export of a single range of an audio track (with no fx) evokes this problem.
Could there be a reason for this, I don't see how the firewire connnection is involved in an export of audio. If the same is done on a crappy sound card there is no problem in exporting.
Thanks
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re. Sents are lost after reopening project
re. I'm not sure this is the right way to do it in qtractor but initially it works and seems the only way to do this.
unfortunately, due to it's internal processing flow, connecting qtractor outs (sends) to any of its own ins (returns) directly is a no show.
in those situations behavior is undefined. fact is, it depends on each track/bus internal processing order which is not deterministic to be exactly the across sessions. yes, it might work once you're doing connections first time but might fail miserably next time you open that very session--evidence is no signal whatsoever passing through, going nowhere but dead silence.
please note that the send/return inserts are provided mostly for you to connect ports to/from external jack clients and not (ever) qtractor own ports--that's the big reason for your case.
re. how the firewire connnection is involved in an export of audio.
both ardour and qtractor make use of a special jack processing mode, so called freewheeling mode, when exporting audio. switching back and forward (internally) from that frewheeling mode might have issues with some drivers (firewire) and not with the vast majority of others (alsa).
all that to say the trouble might be on jack internals and firewire driver specifically, when in face to freewheeling mode switching. i'll advise you to report this issue to the jackaudio.org devs. either via jack-devel maillist or #jack irc channel at freenode.net.
i don't have a single firewire device any near me (never had tbh.) for me to test and repro.the issue, so that please accept my apologies.
cheers
No internal busses
Thanks for your explanation.
If I understand correctly there is no internal system for making fx sent/return busses? All the fx have to be used as inserts then.
I read about the freewheeling, and can see it in the verbose messages. Is there a reason or necessity for switching to freewheeling. Is it a sort of temporary detachment of the audio driver?
The problem only occurs with firewire devices. I'll post it on Jack's mailing list.
Can I ask you what audio devices you use, because all [external]audio devices I used till now (all firewire) - except for the internal pc sound devices or some pci sound cards like m-audio's delta - needing a lot of experimentation and trial/error to get them working.
Thanks again.
re. No internal busses
re. there is no internal system for making fx sent/return busses? All the fx have to be used as inserts then.
kind of. yes. buses in qtractor are not the same as you find on other DAWs;
buses in qtractor are internal mix-down interface devices with no complete resemblance with those of analog studio mixer consoles which all the other DAWs try to mimic. and to great extent succeeded. but not in qtractor, sorry. buses in qtractor have somewhat restricted semantics, so to speak ;)
of course you can have fx inserts in qtractor, either inline (plugins) or external (ie. standalone jack clients), the later being the purpose of qtractor send/return inserts (aka. pseudo-plugins, got that?)
tbh. what's at stake here is one of the qtractor shortcomings, silent limitations, if it makes it sound more softly--you are just advised to not connect any of its (jack) audio output ports to any of its own audio input ports. results of doing that depends too deeply on implementation (ie. code path). and that, my friend, is subject to change by the minute :)
bottom line says there's a contingent from current qtractor DSP flow internal design. yada yada. it might get fixed eventually, circumvented in some near future or never will... but now, i'm sure to tell you that it is not.
re, what audio devices you use?
all that are alsa supported ie. pci, usb and mostly anything else but firewire.
sorry :)
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