Beatmap (non const) 3/4 and 2/3 error in calculation

[Daniel Schürmann]

The algorithm to calculate the new beat position works only for * 2 and * 1/2
Unit tests are missing at well for 3/4 and 2/3 scale, so the issue was not catched,

[Daniel Schürmann (daschuer)]

https://github.com/mixxxdj/mixxx/pull/812

[junglistric (ericzhang)]

Is this a tempo extraction bug or time signature bug?

[Daniel Schürmann (daschuer)]

This issue is about the right click on a track bpm menu and the track preferences.
It might happen that the auto detected beat grid is of by a fixed factor.
You can multiply the bpm value and move the beat markers by the selected values.

This works for constant BeatGrids, but not for BeatMaps with individual marked beats.

Yo can select which type Mixxx will generated with the "Assume constant tempo" checkbox in the beat detection preferences.

[Be (be.ing)]

Can you clarify what goes wrong when scaling by 3/4 and 2/3?

[Daniel Schürmann (daschuer)]

I have just had a second look on the original code, but I cannot confirm my original assumption.
The original code should work for any value. Why did it fail during my test .. ?

But however linear scaling a beat map this way is wrong at all, since if you double the BPMs only the first half of the track has beats.
And if the Track ends with a slow passage, it is moved to the middle of the track.

[Daniel Schürmann (daschuer)]

https://github.com/mixxxdj/mixxx/pull/882

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/8375