Library: automatic/MIDI-triggered combined-filter; contextual to current track (good mixing BPM/key)?

[mxmilkiib]

Feature Description

Current there is no keyboard/mouse-free method to find/highlight tracks that are suitable to mix with the currently playing track(s) in both tempo and harmonic registers.

If filters could be combined, the mechanism could be used on-the-fly to filter down a list of library/crate tracks that are suitable.

See #12211

"A MIDI bind, which, when triggered, makes the library view change to show search results from within the library/current crate that have a BPM and key that are appropriate to mix into from the currently playing track."

This could hopefully be an easier stop-gap method before a visual system to aid harmonic mixing arrives (see #5655).