Add heuristic BPM fix depending on song genre

[spotlesscoder]

Feature Description

Sometimes, when I add new trance tracks with 140 bpm to my library and analyze them, they are detected as 93.3 BPM I want mixxx to show me a dialog after analyzing when tracks are below 122 BPM and either the genre in the Audio Info fields of the files contains "Trance" or the crate I added them too contains the word trance. I want to select these tracks from a list and have some buttons with very common tempos on buttons to re-assign the tempo for the selected songs E.g. 124 BPM, 136 BPM, 138BPM, 140BPM This way I can bulk-fix wrongly detected tempos

This could be done for other genres where such errors which follow a certain pattern are often occurring

[daschuer]

I think we can do it already. Just use the search field to filter you library for: "genre:Trance bpm:80-120" Than you can Ctrl+A and right click to apply a BPM multiplayer. After that you may lock the BPM to indicate verification.

Does that solve this issue for you?

[spotlesscoder]

yeah it think that could solve it. However it would be great to have a very prominent indicator for what is likely to be the correct multiplier for "common missdetections" - for example I added some psytrance to my library and there some tracks were detected with 98.7 BPM and I am still struggling to find out what BPM is actually correct

[daschuer]

Not sure if this is possible.

Can you provide a GUI mock up/edited screen shot for it and the set of rules you have in mind?

[spotlesscoder]

So I realized that 3/2 BPM is usually the correct fix for the misdetections. Maybe it would be enough to highlight that menu entry with an accent color?

[daschuer]

When exactly should it be highlighted?

[spotlesscoder]

The menu entry "3/2 BPM" when I right click the track and go to the "Adjust BPM" menu

[Swiftb0y]

Fyi, the most common misdetection I have are DnB tracks, where the typical rhythm gets detected as 116Bpm (3/2 fixes that) and misalignment by exactly half a bar on house tracks where the grid gets placed on the offbeat hihats instead of the kicks.

[spotlesscoder]

Yes, same for me for Trance, Psytrance, Hardstyle etc. It's usually 3/2 BPM

[daschuer]

When exactly should it be highlighted?

Let me rephrase: To highlight a specific multiplier, Mixxx needs to guess the most likely one. For that we need a set of if -onditions. They should works for most tracks in a reasonable way. What could be the set? Please propose a pseudo code we can use to start with.

[spotlesscoder]

Mixxx could look into the track metadata for the genre or the file path (e.g. when the folder the file is from is called Trance Hits 20xx)

[Swiftb0y]

Most dance music usually has integer BPM, so mixxx could consider doubling BPMs like 87.5 (175 BPM DnB track detected at half speed) or maybe 116 as I pointed out previously...

[ronso0]

So if the detected (constant) BPM have a remainder of .5 (or .6666), Mixxx should try to double it (or multiply with 3/2) and check if the result is in a reasonable range?

[Swiftb0y]

Thats a possibility yes, though I'm not sure if I would let mixxx do these automatically. This was more about just highlighting suggested actions.

[daschuer]

This sounds like a consideration the beat detector should do. I will have a look. We already have a priority on integer bpms and a certain BPM range. Maybe it possible to shift it a bit.

@spotlesscoder in terms of a general purpose rule, we have not one that we can turn into code. Can you give some explicit examples?

[spotlesscoder]

pseudocode:

if genre.toLowerCase().contains("trance") && bpm < 100; then multiply bpm with 3/2; fi