Automation Bug, Spikes at the beginning of a line, with an Instr. MIDI Control device linked to a VST3 plugin

Hello everybody,
I’m pretty sure I discovered an envelope automation bug in renoise.
This bug happens only if an automation point is exactly at the beginning of a line AND at least one other automation point is placed before the next line begins.

Current (buggy) playback behaviour seems to be like this:
At the beginning of each line, Renoise scans what is the automation value at the end of this line, sets this automation value for the duration of one tick (at a beginning of the line), then contiues the other ticks with the correct values.

Correct behavior would be like this:
Renoise would not set the automation value of the end of the line at the beginning of the line (for one tick).

It’s hard to describe, so I will upload a xrns file.
It has a VST3 dependency (Surge XT), but you can replace it with another synth.

Please open the envelope curve of Doofer Macro1, watch the line numbers, the placement of automation points, and listen to the pitchbend automation.

Thank you!

My System:
Debian AMD64
Renoise 3.4.4

BUG_Spikey_Automation.xrns (16.0 KB)

I’ve now bumped your forum user permissions, so this should be possible.

Would be nice to hear/see some examples here.

Thank you, taktik. I uploaded an example xrns in the original post.

Thanks for the example. There is indeed something fishy going on here.
If you place the target point on a full line (line 5 in your example) it will work correctly.

Working on a fix…


Problem found. Will be fixed in the next update.

If you need a workaround for now, use an “Instr. Automation” device instead of an “Instr. MIDI Control” device. The error only happens in the MIDI Control device.

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Thank you! :grinning: Waiting for the next update.