Problem during export of composition

[ApexSoundMusic]

Hi all,

I've took the step to purchase Mulab past weekend and already have a new track done with it. Thus far I'm happy while using it.

Unfortunately though I encountered a problem while exporting. I use the export composition as audio file option to render the track, after which the progress bar shows up. The render seems to be successful untill roughly 2/3 of the process. At this point the progress bar just comes to a stand still/freezes. I've tried aborting the eport using the esc button to no avail, also when I click somewhere in either the Mulab UI or the progress bar pop-up the whole program just shuts down. Leaving me with an audio file in which no audio is present.

I suppose the point on which the export freezes corresponds with the same time based point in the track, although the VST's I used and sequences I've built are all used earlier than that 2/3 mark. So I'm not sure what is causing the problem.

Has anyone encountered a similar issue and knows what to do to resolve it?

Also, I would gladly try myself to pinpoint the problem (if it is a third-party VST), by trying to export the track without some parts. But in order to do this: Is it sufficient to just disable a composition track or a plugin on the mixer rack? Or do I need to remove the plugins one by one completely to track down the issue?

Thanks in advance for the help!

[MuTools]

First of all:

Which MuLab version?
Which OS and version?

Also, I would gladly try myself to pinpoint the problem (if it is a third-party VST), by trying to export the track without some parts. But in order to do this: Is it sufficient to just disable a composition track or a plugin on the mixer rack? Or do I need to remove the plugins one by one completely to track down the issue?

Well it depends on the problem, but i'd surely first start with simply disabling tracks and that way try to find the track that is causing the problem.

[ApexSoundMusic]

I'm currently running Mulab 8.5.4 on Windows 10 build 18362.778. I can also try updating Mulab since I saw a new version is released just today.

[MuTools]

FYI: The new M8.6.9 version still is a beta version, though very close to release so you can give it a try indeed.

[ApexSoundMusic]

Okay, good to know. When do you expect it to be released?

With regards to my tests: I've succesfully exported the kick, bass, other percussion tracks. So I started to add other tracks in my export and it went sideways immediately on the following track.
So I tried exporting that specific track isolated, which was unsuccesfull of course. Then I tried another export on which I removed all effec plugins from the mixer rack, also unsuccesfully.
This leads me to suspect that the Synth vst for that track is the issue, the weird thing however is that that same VST is also used on other tracks, among which also a bass layer (which I exported successfully).

Perhaps I need to check the synth parameters to see if something is off...

The synth in question is 2GetherAudio's G8tor synth by the way.

[ApexSoundMusic]

Okay, little update: Just now I was able to export that specific track... The trick was muting the automation sub channel underneath that track. The automation was applied to the synth's filter cutoff. Have you encountered something similar before?

[dakkra]

Are you automating the parameter directly or via MIDI? It seems like the synth in question doesn't like automation during export. It may be worthwhile to check it other parameter automations will cause hangs during render. Also may be worth checking to see if the similar setup will crash in another DAW (Cakewalk by Bandlab or Tracktion Free would be decent ways to test this for free). This way you can isolate if it's the VST synth itself that's causing the issue during render, or the interaction between the synth and Mulab.

[ApexSoundMusic]

Thanks for the Reply Dakkra. I was indeed thinking of this myself and wanted to test it out in FL Studio (Which I also have installed). This way I can check whether the problem only happens in Mulab or not. Didn't get to it yesterday though, but will try it out asap!

Your idea of trying automation on other parameters is one I didn't think of yet! Will try that out also. I feel these are things I can also pass back to the plugin developer.

Also, since I now am fairly sure that it is the automation, I might also be able to work around it by adding effect filters on the racks and automating them. Surely not the fanciest solution but it might 'unblock' this project for now.

[MuTools]

I've not received any similar reports about the MuLab Export to audio file functions. If it only happens with that single VST, then i'm suspicious it's a specific issue with that VST. Indeed best to isolate the issue as much as possible and try it in other hosts as well, but take care using the very same samplerate, blocksize and multicore setup in all test cases! Also good suggestion of Dakkra to also try automating other parameters.

[ApexSoundMusic]

So I did some new tests.
Firstly I added the plugin to FL Studio. Used the same preset and made a loop with an automation curve on the filter going from 0%-100%. I then did 2 exports.
Both were with 16-bit, the same as the setting in Mulab. Then I tried with my default buffer size as well as a much shorter buffer size since I understood this is related to the block size. Either way the exports succeeded without problems. With regards to the multicore setup, I'm not entirely sure how to change these settings. But if I'm correct then Mulab makes use of this, while in FL Studio the check on 'multi threaded processing' on the plugin is on. Hope this applies to the same.
Anyway my conclusion based on this test is that I cannot reproduce the issue in FL Studio.

Then a new test in Mulab itself: I again isolated the G8tor track and removed the automation sub-track. Then I added a new automation track, this time just automating an OSC level. Then, upon exporting, the process again 'hangs' just as it was the case with the cutoff automation.
So it seems that the problem isn't limited to just 1 plugin parameter.

I cannot say that this problem has entirely something to do with Mulab, my technical knowledge about the program is to limited to make such a statement, but based on these test I would say it is something between the interaction of the plugin with Mulab specifically. Is this information you can do anything with?

In the meantime I also notified the developer of the plugin so that they can also have a look into it. I'll make a copy of the project and see if I can replace the automations by using effect plugins.

[MuTools]

Then a new test in Mulab itself: I again isolated the G8tor track and removed the automation sub-track. Then I added a new automation track, this time just automating an OSC level. Then, upon exporting, the process again 'hangs' just as it was the case with the cutoff automation.
So it seems that the problem isn't limited to just 1 plugin parameter.

Please do this test:

1) Make sure you have a reloadable project so that when you export that project to audio file, it hangs.

2) Restart MuLab and reload that project.

3) Now simply replace that G8tor VST by another VST. It doesn't matter which VST, you also don't have to check whether it sounds fine. Just replace it via right-click on that G8tor -> Replace -> then choose any other VST from a different manufacturer.

4) Retry the export.

Does it hang?
If it doesn't hang then it's G8tor.

[Big Tick]

@ApexSoundMusic I just tried with G8TOR and Mulab 8.5.4 on Win10 - recorded one note, added automation of filter cutoff, export to audio. No hang here.

You might need to send us (at sales@2getheraudio.com ) your Mulab project (ideally streamlined to use G8TOR only) so we can have a look what's going on.

[MuTools]

Thx for joining this topic Big Tick

[Big Tick]

No problem. I thought maybe Mulab does something funky with threading during export, but so far no luck reproducing the issue here.

[MuTools]

To exclude any threading issues: ApexSoundMusic pls go into MuLab Audio Setup and set Num Audio Processor Threads to 1. Then do that same export that repeatedly hangs. Does it still hang when only using a single audio processor thread?