Shooting Video - Slo-Motion to Normal Motion - rate?

PlasmicSteve

PlasmicSteve

Member
Hello. I'm going to be shooting a video of my band, and for the performance part I'm going to shoot the band in slow-motion on my HVX-200a, but performing to a sped-up version of the song being played back, so we're in sync but our motions are slowed down (I know I'm not inventing this).

I've been doing some tests on speeding up the song, but I can't get it right.

At first I thought the slow-mo speed on the HVX-200a was exactly 200 percent, so I sped up the song that much, but the test was way off.

Then I read that the frame rate of the slow-mo was 50 fps - and I thought, 50 over 30 (normal frame rate) = 166.66 - so I sped the song up by that percent, but I was still way out of sync.

So before I spend more time on this, I wanted to see if anyone had the answer - the percent I'd have to speed up an audio track to make it match a slo-mo video track (I hope that's clear).

Also, I'm shooting in 24p, though I didn't think that would make any difference.

Thanks!
 
ok, lets go step by step on this one,

Hello. I'm going to be shooting a video of my band, and for the performance part I'm going to shoot the band in slow-motion on my HVX-200a
Click to expand...

by shooting the band in slow motion:

A - your going to shoot the band in a higher frame rate(like 48, 60, 72, 96, 120)
B - your going to slow time and shoot in normal frame rate(like 24, 30)
C - your going to shoot in normal or high frame rate and tell the band to speed up or slow down(their movement) to make it look like they are slowed down or sped up when the video file is played in normal speed or also slowed down to increase the effect.

but performing to a sped-up version of the song being played back, so we're in sync but our motions are slowed down
Click to expand...

if your going the 24fps, speed up the song 2x, and shoot the band at 48fps. put it on a 24fps timeline and slow it down 50%, remove blending.

test that with a small sample first, see if that was your desired output.

p.s.: try to be more clear so members can help you out.
 
Here's a great example of the method you're talking about by sean mcleod who's here on the forums...

http://www.sean-mcleod.com/smc/work_videos_pd.html

The process mentioned above is correct. However, "slow motion" is not any specific frame rate. It simply means that the content is played back at a slower rate than it was recorded.

First choose your target frame rate that your final production will be - Probably 24 (23.97) or 30 (29.976).

Let's just say your final production is to be 30fps and the highest frame rate your camera can shoot is 60fps (twice as fast as your target). If you shoot at 60fps and play it back at 30fps (by stretching your footage by a factor of 200%) the performers will look like they're playing at half speed. So for it to look like they're performing at regular speed with the footage slowed down, they have to actually perform at twice the normal speed so that when the time is stretched, they look like they're performing at "normal" speed and sync with your audio track.

The above scenario is of course for a 200% stretch and wouldn't necessarily be the correct math for lets say, a 60p to 24p conversion.

Basically, your concept of the method is correct - just make sure your math is correct and that you're actually using the correct frame rates for your math in both your recording and editing.
 
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Amr, sorry you were confused by my post. I thought it was as clear as it needed to be.

Jeff and Barrry, I appreciate your help - the formula is great. That's what I was hoping for. I thought about using 48 fps, but I really wanted it as slow as possible, so I'll use the formula for that (250%). Thanks - and the Sean McLeod example is great, too.
 
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