I use the ACW in RealBand to tempo map live drums
you then write the metronome to a midi track
drag the mid into Reaper import the tempo map
drag the drum wav file in and you have it
to go one step further
insert stretch markers at each beat
remove the tempo map from the master track
and snap stretch markers to grid
this will give you quantized drumming.

The vst will have an export midi chords tempo map midi drag export to give the DAW a tempo map and midi chords for virtual instruments.
It will also have in import midi tempo map from the DAW.
The midi will also give the time signature changes.

The old ACW will be easy as it's there now and will popup with one command to bbw4.exe

Biab box don't have decimal point tempos so it's always changing
see first pic import tempo from RealBand, the second pic is manually inserting changes into the plug:

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BiabVST-Import-RB-SGU.png (158.04 KB, 99 downloads)
BiabVST-Save-Decimal-Tempo.png (161.63 KB, 100 downloads)