SLOMO Syncing with audio help!

[agentjonny]

alright, planning on doing alot of slomo for a music video shoot. need to know how fast to speed up the audio track so it will sync up in post. 60p slomo into a 24p timeline. i'm using Soundtrack to do my audio editing, so i know that 60p slomo is 60% speed, but how do i do the math for the audiofile speed up?
i haven't taken a math class in years, someone should do a chart about this!

[Luis Caffesse]

Well, if you're shooting 60P and you're playing back at 24p....
that means that you're slowing your footage down by 2.5 times.
(60/24 = 2.5)

So you'll have to speed your audio up on set 2.5 times for it to match up (or 250%).

[agentjonny]

so, is the math framerate/24=speed up?
seems easy enough!

[Barry_Green]

NO!

Only for certain frame rates, being 24, 30, and 60. That math will not work for any other frame rate combinations. You have to search for the thread where I did all the calculations and laid out what the speed percentages need to be.

[THX-1138]

A very smart man helped me out with this on cinematography.com

For a 24 fps base:

24 / n
n = frames per second you want to shoot

So if you want to shoot at 32fps = 24/32 = .75 or 75% -> so you'll want to reduce the length (speed up) of your music to 75% is real time length. So if you have a 4 minute song (240 seconds), you'll want to reduce (or speed up) the song to 3 minutes (or 180 seconds). 240x.75=180

The main things to remember are that frame rates may be and are slightly different on the HVX

IE: 24fps is actually 23.98

The manual gives all the real frame rates



One easy way I do this is add the click track at the begining of the song - so the band knows where to come in playing.

Make that one whole audio file

Then I use the total seconds of that new file for all my calculations.

Also... get the 48 or 60 files to the band for practice. Blindsiding them with that speed on a pop song usually gives poor results.