Double Check Me Here: Shooting a Music Video at 30fps to Slow to 24

[kevstauss]

I'm shooting a music video at 30fps and slowing it down to 24 in post. Double check my math here: I speed up the song by 25% to use as a reference track for lip syncing, shoot at 30fps, slow the video down by 20% in post, and the original song syncs perfectly, yes?

 

[clang]

Using an example 5 minute song just to keep the maths easy, you'd definitely need a 4 minute reference track, which you'll later slow down in post by playing the 30fps footage at 24fps to make it 5 minutes again...

But as to the percentages to enter into your software, that may even depend on your specific software. Percentage of native frame rate or percentage of normal frame rate? - my head hurts

Strongly recommend simply creating a reference track (perhaps even a video version with just someone tapping the rhythm), and then experimenting with the percentages. You sure don't want to discover you were wrong after the shoot

 

[kevstauss]

For anyone who finds themselves in the same position, here's what worked for me:

I sped up the music by 25%, played that on set while shooting on my Canon T2i (this obviously applies to any Canon DSLR) at 29.97fps. I brought the footage into Premiere, conformed it down to 23.976fps, and synced it with the original song. Bingo, perfect match!