Sound Design Stack Exchange is a question and answer site for sound engineers, producers, editors, and enthusiasts. It only takes a minute to sign up.
Sign up to join this community
I'm working on a project for a music video where we're attempting to record video with a sped up version of the song, and then slowing down the video to match the original recording.
anybody have any experience with this? i'm looking for insight on how much to adjust the speed of the edited song to match up with the change in frame rate or time code.
If you are going to be slowing down the video by 2x, you speed up the click track/music by 2x.
So let's say the video is shot at 60 fps, then it's slowed down to 30 fps. Since the final framerate is 30fps, that's also what the music will be synced to at normal speed. Let's say the music is 120 bpm normally. It's rate has a 1:1 relationship with the music video's final framerate, in this case a clean 30 fps. So if you are shooting at 60 fps: 30/60 = 0.5
That's the ratio, so to get the bpm you want to use when shooting, just divide your starting bpm (120) by the ratio. 120/ 0.5 = 240
If your final framerate is 29.97, but you are shooting at 60 fps: 29.97 / 60 = .4995 So with a 120 bpm track: 120 / .4995 = 240.24024
It's a linear relationship. You just need to know A) The original framerate B) The final framerate C) The original bpm
EDIT: From the comments
[new bpm] / [old bpm] = [original framerate] / [final framerate]
Solve for [new bpm]
a / b = c / d
a = bc / d
I haven't personally had any experience with this but it sounds like something one of my lecturers from the easy rollers talked about what they did in the film Lock Stock & Two Smoking Barrels. check it out on youtube and contact them they might be able to help!
We just did this for my bands music video - we filmed at 50fps and slowed it down to 30fps. it might be worth considering how tricky the song will be to play at 1.6 or 2 times the speed- we were rather struggling at 1.6! The end results are really great though, gives a very serene glossy look to everything :-)
