MIDI file tempo?

I occasionally convert sequenced video game music formats, to do arrangements/remixes and whatnot. But I can’t seem to replicate the exact tempo of some songs (doing a direct side-by-side comparison completely within Renoise reveals a de-sync eventually).

When you import MIDI files into Renoise, it writes the BPM into the actual song pattern (a rounded tempo). Is this the value that’s actually used internally, or is Renoise in fact using the exact MPQN (microseconds per quarter-note) tempo specified in the MIDI files “behind the scenes”?

The tempo may be quite exact in some cases, so just lowering or raising the BPM by 1 doesn’t help.

You can enter fractional BPM in Renoise.

If you want to tap the tempo of some song, try to tap 4 beats or even more to get a more exact figure. Then multiply accordingly.

Another thought off hand is if you know the microseconds per quarter-note value tempo from the midi file, manually convert to BPM, delete the rounded tempo pattern commands and then set the BPM to say 100.23 or whatever fractional number the calculation comes out. I suppose if there are tempo changes during the song however, things can get more awkward. Maybe write the midi file tempo (as an option) changes in the BPM automation lane.