33  Beat and Tempo Estimation in Capo

When Capo analyzes your song files, it’s not just calculating a BPM value and applying that evenly to the song. Rather, it tries to map out the eighth note (or triplet) pulse over the recording, allowing it to handle a little bit of drift over time—very handy in live recordings.

The detected Tempo that’s reported in the speed controls is calculated based on the average space between beat marks, and it is unlikely to match your own tempo measurements calculated over a few bars using a “tap tempo” metronome.

Each beat mark that Capo detects is stored in the project, and when you use the metronome and count-in features, the click track you hear is playing those values at the precise time they’re stored, and the click is accurate to the recording. By contrast, if Capo had simply “run a metronome” alongside the playback at a constant BPM, it would drift in and out of time with the recording.

After the beats are detected, Capo runs a downbeat estimation process separately to determine the start of each measure. Unfortunately, Capo’s method of downbeat estimation is unable to work with odd or changing time signatures. That’s why we offer comprehensive beat editing tools to let you override the detected grid.