How To: Sync Slow-Motion With Audio???

[Aram Rian]

hi guys.

a first-time EX3 user here. just about to shoot a slow-motion music video with an EX3. i fully understand (i hope i do! :)) ) all that the manual says about the procedure. however, how do i synchronize the picture with the audio track? i mean - how do i figure out what speed the audio track should exactly be set to, when shooting a slow-motion video ("over-cranking"), so that it plays back correctly when the video is played back at its normal speed? for example, if i shoot the video at HQ 720/60P, how fast should the audio track be (1.5 or 2 or 3... times faster), so that it sounds right when the video is played back at 720/24p or 720/25p ?

thanks in advance.

[Denise Wall]

I'm not certain what you mean by changing the audio speed (won't that distort the music?) but back in the 80s The Police did a slo mo video with Wrapped Around Your Finger:

YouTube - The Police - Wrapped Around Your Finger

It wasn't the audio they changed but instead Sting mouthed the words at twice the speed of normal. Then when slowed down, it roughly synced with the audio, which was played at normal speed.

[Aram Rian]

i meant the procedure commonly known as slow-motion lip synchronization.

[Steve Pond]

Well, if you're overcranking, the camera doesn't record audio. You have to set the frame rate at 60p in order to capture the audio, and it will be in sync with the video in post as long as you leave the audio track linked to the video. If you record at 60p and simply render the video in post at 24p or 25p, the audio will remain in sync and at the proper pitch. If you're not intending to use the clip in question for slow motion, I would suggest recording it at the same frame rate as you intend to use in the final rendered video. If you ARE using it for slow motion and you cut the speed in half, then keeping a voice synced becomes just a little more tricky. The pitch changes and sounds a little funky, so you'll need to adjust the pitch in post so it sounds more normal. It will still be really slow, but a pitch adjustment will keep a woman from sounding like a 280 pound linebacker. Hope that helps.

[Aram Rian]

thanks a lot, Steve, much appreciated, but i actually meant that popular effect in commercial music videos, when everything is in slow motion, while the performer's lips move at a normal speed - that's AS IF, because when shooting the video the performer would actually be miming to the sped-up version of the audio. so my question was - if i shoot the video at 50p or 60p, how much am i supposed to speed up the audio on a separate audio-player, so that the mentioned effect is achieved during playback?

[Hiram Yates]

it depends on the frame rate of you're timeline... For example, if you're shooting 60p and dropping into a 24p timeline, 60/24 = 2.5 times faster... or in a 30p timeline, 60/30 = 2 times faster, and so on.

[Aram Rian]

so for 50p/25 - that would be 2 times faster.
and how about 50 / 24 ?

[Bo Skelmose]

Hi
That will be 208.3333. Why not 60/24 - that will be 250% - I guess....