PCs effects work during playback but not during rendering

[anosci]

hi there, I'm trying to make my own VST

however I've encountered quite a problem: any automation (PCs effects) I add will not work during the render.
it sounds fine during playback, but when rendered, the last known value for each parameter becomes constant.

I've tried stripping down my plugin to see if it was a problem on the coding side and...no such luck.

here's a link to the relevant files, and references:
https://dl.dropboxusercontent.com/u/149306395/why%20does%20this%20not%20work.zip

strangely, only some parameters are affected. (the attack seems to work fine in playback and render...but it's no different from the Sub volume, as best I can tell.)

any ideas what's going wrong here?

/sci

[Saga Musix]

You are using FlowStone / SynthMaker, right? Funny timing, because I have just discussed this issue with other people this weekend and came to the conclusion that it's a plugin bug and not a host bug - this only happens with very few wrongly coded plugins and it also happens in Reaper. Maybe this topic helps you: http://www.kvraudio.com/forum/viewtopic.php?p=5578209#5578209

[anosci]

indeed I am.

huh.

that topic isn't quite as helpful as I'd like for it to be, but I think this guy is on to something:

I suspect it has something to do with the interaction of 'stream',
which does render flawless-
and the green pins(float,int etc.)
The green stuff doesn't run at samplerate.

I've been tinkering with my schematic a bit since reading through that thread and...that seems like it might just be the problem. >_<

edit: confirmed for problem.
a "de-zipper" module seems to trip everything up in my VST.

remove that and the paramaters are automated!
...but that was basically an interpolation device. so that's a bit of a concern now.

[Saga Musix]

Well, I am not familiar with SynthMaker, so I cannot help you with the details here. But basically what you want is to be independent of any system timers and only interpolate based on the stream position, or the time within one rendered frame (depending on what you want to interpolate). Otherweise, you could of course participate in that thread and ask how to do it properly.

[anosci]

yeah I'm not sure how to tackle it, but I did discover something nice:
the "smooth" part of "Parameter Control smooth" actually bypasses the interpolation problem for the most part!

it's not ideal, but it's good enough for me.

what concerns me, though, is that the problem piece was actually a pre-built module included by default within flowstone. that seems like it could become a recurring problem.

I hopped in the discussion on KVR, so let's see what I can learn from there.

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just as an aside: thanks for the speedy reply and for the software in general. openMPT has been my main DAW for 8 years now. I appreciate all that you've done for the program.