Change BPM: fraction bpm-change result preview

[Milkii Brewster]

So far, it appears to me that if Mixxx gets the tempo incorrect, it gets it incorrect at some fraction of the actual bpm.

This is why the 'Change BPM' submenu has entries to adjust the number by some fraction.

But I would suggest that many cannot think in these terms and could compound the problem, something stressful whilst trying to mix.

My suggestion would be an option in the 'Change BPM' submenu for 'Tap to detect fraction change' or something; because whilst a tap tempo might (probably won't imho) give the correct bpm, it will (most likely) give a bpm near one of the resultant bpms from the fraction change options that are available, thus alleviating that choice from the user.

[ronso0 (ronso0)]

Are you actually askinf for a 'Round BPM' action button?

related: lp:1882776 "increase BPM tap filter length"

[Milkii Brewster (mxmilkiib)]

Not here, though I did recently make a specific UI suggestion for "Round scanned BPM values" lp:1796262

I'm more meaning that, if I want to play a track, but the bpm is wrong, (and assuming Mixxx bpm detection is only off by a ratio) I think there is a middle UX possibility between a) having to work my brain about what bpm change ratio I should be applying (and maybe how to reverse/reset/fix if I get it wrong) and b) hoping that I can precisely enough tap out a "bpm" that'll get me to the middle/end of the track.

A sort of relate-taps-algo-bpm-with-feature-detection-algo-detected-bpm-to-fix-bpm thing.

[ronso0 (ronso0)]

okay, now I understand.

I see two ways to fix the situation:
A) in the track context menu > BPM submenu, have a BPM conversion preview next to the conversion factors like 2/3 (174 BPM)
B) add a 'Tap correction' action to the track context menu > BPM submenu that opens a dialog that
* allows to tap
* multiplies BPM with all available fractions [2/3, 3/2, 4/5, 5/4]
* picks the one that comes closest to the tapped BPM)

( detected BPM )
[ TAP button ]
( tapped BPM )
( assumed target BPM )
[ Apply ]

I think we should go with the BPM preview ;)
Imo the fractions we have available produce BPMs that are easy enough to distinguish, right?

From the library table, this would work for single tracks only though.

[Milkii Brewster (mxmilkiib)]

> I think we should go with the BPM preview ;)

Haha, you make a very good point :)

> Imo the fractions we have available produce BPMs that are easy enough to distinguish, right?

Sure, it appears a fair balance for humans.

[Milkii Brewster (mxmilkiib)]

Having thought about it and tried some more, the next logical question after "what if you don't understand the fraction?" is "what if you don't understand the bpm?", as in, the user doesn't know what that bpm number "means". So, to channel some Bret Victor, would it be too much to have the lines in the change-previews submenu finish visually with a dot that flashes at that bpm?

[Daniel Schürmann (daschuer)]

How about just add a checkbox
[ ] pick closest fraction when tapping.

[ronso0 (ronso0)]

"what if you don't understand the bpm?"

Is it not sufficient to see/hear the relation of vertical strokes on the waveform to peaks in the waveform shape?
If a user doesn't know what the BPM number means why would s/he want to change it?
Whenever I introduce formerly non-DJs to Mixxx and they don't know about BPM, they usually also don't care about it and don't touch the pitch slider, let alone Sync or Quantize controls.

"would it be too much to have the lines in the change-previews submenu finish visually with a dot that flashes at that bpm?"
That would make sense IF the respective deck is playing, but IMO it should then also be aligned with the 'real' downbeats, which _probably_ hard to achieve if Mixxx detected the wrong BPM in the first place.

Let's go with the BPM number preview first.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/10128