BPM Math
Posted: Sun Apr 06, 2014 20:51
What math is used to determine a clip's default beat length when switching from Timeline to BPM Sync transport mode?
This is a tricky one:
It takes the current length of the clip, and then tries to come as close to playback at normal speed as possible, rounding off to multiples of 4 beats (1, 2, 4, 8, 16, 32, 64, etc), assuming a default master BPM of 120.
So when your original clip length is 8 sec, it would play back at the same speed in 16 beats at 120 BPM ( 1 beat at 120 BPM is 0.5 seconds). So the setting defaults to 16 beats when you switch to BPM Sync.
When your original clip is 9 seconds, it also 'snaps' to 16 beats, because multiples of four just make more sense for modern dance music. So it will play slightly faster. But if you have beat-based animation or edits in your clip, and you made sure they're set to a 4/4 time measure, it will still sync up.
Does that make sense?