Time lapse - sort of

Crellin Sound wrote on 3/5/2012, 6:46 AM
Hello There,

I need to do a shot that captures a several hour construction process. Then I need to compress it into about 30 seconds.

Never having done this sort of thing before, I figure I'll turn the VG20 on and just let it run for whatever time it takes to capture the process, say two to four hours. Then I'll import the file to Vegas and just run the entire file in 30 seconds. People should be whipping around pretty fast, if I do that.

Do you have any comments on this procedure? What should I watch out for? What camera settings should I use? Should I use a fast shutter speed or a slow one?

If there's a better way to do it, please let me know? I do want to be able to see people blurring around really fast, if that's possible.

Thanks,

BT

Comments

Steve Grisetti wrote on 3/5/2012, 7:12 AM
There is a limit to how much you can speed up a clip -- so you may not be able to squeeze four hours down to 30 seconds in one pass.

You may need to speed it up as much as you can, then output your video as a DV-AVI, add the speeded up clip to another project, speed it up as much as you can, output that as a DV-AVI, etc.

BTW, note you're going to be speeding things up about 500x, so don't expect to see much in terms of people. It all may be moving way too fast. You may actually only see the clouds in they sky and the movement of the sun.

And, of course, use a locked-down tripod!
TOG62 wrote on 3/5/2012, 8:44 AM
For this amount of speed-up I think it would be better to shoot a set of stills. VMS can only speed up by a factor of 4, so that an awful lot of passes to get to 500.
abelenky wrote on 3/5/2012, 10:34 AM
There is an alternative to multiple passes of speeding up the video by 4x.

Instead, render the entire video as a sequence of JPG or PNG frames.
While this will take up a LOT of disk space, it'll only be temporary.

Once all the Images are rendered, just delete most of them.

(My rough calculations show that for 2 hours, you need to delete 239 images for every one you keep. For 4 hours, you need to delete 479 for every one you keep).

You should be able to do accurate mass-deletions with some basic scripting, or some careful math and the Windows Explorer (eg. set the view to be 10 thumbnails wide, then delete 24 rows at a time....)

Once you've reduced it to just a few images, import them all, at 1-frame each, and render your final movie.

This approach might require more human-brain power and a bit of math, but I think it'd be faster in the end.
Crellin Sound wrote on 3/6/2012, 2:12 AM
Howdy,

You all have some interesting solutions.

Lock down the tripod? I'll cement it into the floor. It won't go anywhere.

Too bad VMS will only speed up by 4X Will any other editors speed up by a higher factor?

One suggestion by Abelenky proposed rendering as JPG or PNG frames. Does anyone have a preference on which to use?

Any other ideas?

This whole project is going to be one of those "interesting things" that we all run across from time to time.

Thanks for your help.

BT
altarvic wrote on 3/6/2012, 11:24 AM
> "Will any other editors speed up by a higher factor?"

Even Sony Vegas Pro has limit of 12X. But it supports nested projects, so you can speed up the clips to 144X.
And 10000X if you use Rocket Speed from Vegasaur toolkit ;)
Chienworks wrote on 3/6/2012, 2:20 PM
4x4x4x4x4 = 1024, so it's only 5 passes to get to 500. And remember, each pass goes 4 times quicker than the previous pass.
Crellin Sound wrote on 3/15/2012, 4:49 AM
Hello Everyone,

Very good answers.

Sorry about not answering earlier. As far as I can tell, there's no way in this forum to be notified of replies to posts.

BT