I have a track that I'd like to create an animation for. I'm creating the animation dynamically with code, so I need to know the intervals between beats to sync the video with the audio. I opened up Audacity and ran
Analyze > Beat Finder..., and then calculated the milliseconds between two of the labels it generated, which turned out to be around 500 milliseconds, or 120 beats per minute. The problem is that when I try to animate something in my video to match this tempo, after a while it becomes visibly out of sync.
So my question is: how can I determine if it's my animation that's out of sync or if the audio's tempo is "shifted"; i.e, the tempo remains the same but there is a pause that's not a factor of 500 ms? For example, if each of the two dots below represent 500 milliseconds, how can I determine if a break like the one in the middle occurs?
Edit: Or put another way: if I animated a square to flash every 500 milliseconds from the first beat of a 120 BPM track, and at some point the flashing went out of sync, how could I determine where in the track the sync was broken?