# Edge cases in analysis frames

**URL:** <https://discourse.flucoma.org/t/edge-cases-in-analysis-frames/524>\
**Category:** Usage Questions\
**Created:** [June 16, 2020, 9:00pm UTC](https://discourse.flucoma.org/t/edge-cases-in-analysis-frames/524 "2020-06-16T21:00:27Z")\
**Posts on this page:** 1\
**Showing post:** 28

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**Author:** ![rodrigo.constanzo](https://discourse.flucoma.org/user_avatar/discourse.flucoma.org/rodrigo.constanzo/32/12_2.png) [@rodrigo.constanzo](https://discourse.flucoma.org/u/rodrigo.constanzo)\
**Post date:** [November 3, 2020, 1:53pm UTC](https://discourse.flucoma.org/t/edge-cases-in-analysis-frames/524/28 "2020-11-03T13:53:19Z")

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Perhaps not surprisingly, this “envelope extraction” works better on longer stretches of audio.

Here is 100ms windows (my longer “[predicted](https://discourse.flucoma.org/t/regression-classification-regressification/547/8)” bit of analysis). At the moment I’m using the same analysis/fft settings (256 64 512), but with a larger overall analysis window (4410).

 ![Screenshot 2020-11-03 at 1.48.10 pm](https://discourse.flucoma.org/uploads/default/original/1X/2e1e5442a1a9b98a8dab81d86ea8b05402be4c7a.png)

 ![Screenshot 2020-11-03 at 1.47.22 pm](https://discourse.flucoma.org/uploads/default/original/1X/eaef2e9ee5233a59cbc13547c74c0d7aef78e57e.png)

 ![Screenshot 2020-11-03 at 1.47.12 pm](https://discourse.flucoma.org/uploads/default/original/1X/45482390099bf74bf69dd53933151d24a95b23e5.png)

 ![Screenshot 2020-11-03 at 1.47.05 pm](https://discourse.flucoma.org/uploads/default/original/1X/1549cd458a1cd03de7936dfe50d9d30eb30081c2.png)

In this context, I think the mean-per-frame is better than the peak-per-frame. Also with so many frames, I think the overall gesture/contour is the same, with the peak version just being a bit step-ier.

What’s also somewhat surprising is how the centroid behaves over time. I expected a bit more of a rolloff or some kind of change over that analysis window, but it appears to be largely flat. I checked other spectral descriptors as well (not massively thoroughly), but most show similar (lack of) contours. I guess that’s the nature of this being a single “attack” or “moment”, as opposed to some kind of morphology that changes centroid/timbre over time in a more overt way.

There’s also more meat on these bones as well, which could serve well for the kind of [contour/envelope analysis discussed in this thread](https://discourse.flucoma.org/t/categories-descriptors-for-contours-envelopes-and-morphology/693/9).

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