It would probably not be practical just because you'd need extremely long Fourier transform windows. At 100bom and 44.1khz, downbeats are 26000+ samples between

It would probably not be practical just because you'd need extremely long Fourier transform windows. At 100bom and 44.1khz, downbeats are 26000+ samples between downbeats. It may work with shorter windows for music that is rhythmically complex (more subdivisions would be analogous to more harmonics in the typical pitch detection application) but would certainly fall apart at lower tempos.