Fluid.bufampslice~ not working correctly (when using numframes)

Bug Reports and Issues
1

Putting this on here (rather than directly onto github) as I’m not entirely sure if I"m overlooking something silly.

So I’m building a cascading onset detection thing using fluid.bufonsetslice~ followed by fluid.bufampslice~ and when testing things in context, I’m noticing that fluid.bufampslice~ is rarely returning valid values when I use the @numframes attribute.

In this example if I analyze the whole buffer (jongly.aif) I get a bunch of onsets detected (notably not including the first onset), but the moment I add @numframes 1024 I don’t get any onsets at all anymore. Only when I change @numframes to a huge number (8192) do I start getting onsets again.

It seems like this is broken to me?

The only thing I can think of is there’s some window being applied when using @numframes, but even with that, I would think that adding a @startframe offset would compensate for that, but still nothing.

Screenshot 2023-07-11 at 11.01.04 PM
Screenshot 2023-07-11 at 11.01.04 PM1469×620 81.8 KB 


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2

In thinking about this a bit more I remember way way back when I was first wanting to make sense of fluid.ampslice~ that there was something about the envelope followers getting pulled towards -INF with synthetic signals so normal-ish thresholds would take a really long time to respond. I don’t know what change was made but it was eventually addressed in a fluid.ampslice~ update and I’ve been using it since. Perhaps this wasn’t ported over to the offline .buf version?

This would make sense since when analyzing the whole buffer that it would behave reasonably, but when doing isolated bits it doesn’t have enough time to respond. This would also explain why the first onset is being missed in jongly when analyzing the whole buffer.

3

(turned this into an issue on the git)