Time Compression - What is the Max?

Peter Vred wrote on 8/20/2007, 6:37 AM

I am trying to reduce a 15 minute AVI clip recorded on a mini-dv.
By pressing control and dragging the end of the file,
I am able to squeeze it down to 3:41, but need it shorter.

Is this a limitation of Vegas and video due to number of frames?
Or is it possible to go shorter?
How?

Thanks!

Comments

farss wrote on 8/20/2007, 6:58 AM

You can render it out at that level of speedup and repeat the process.
There's no limitation on how fast you can makes vision go, slowing it down is where you quickly hit the physical limit.

I'd guess though that working in multiples of the frame rate will yield the best results. One simple way to do this is to switch the ruler to absolute frames and the drag the end of the clip so it is say exactly 1/3 the number of frames, render and repeat, if needed make the next one 1/2 the number of frames.

Or else for extreme speedup use a timelapse utility, I think SCLive has this.

Bob.

rs170a wrote on 8/20/2007, 6:59 AM

Inserting a Velocity envelope at the same time will give you another 300% speed increase for a total of 1200%.
If that's still not fast enough, you'll have to render the clip and do these two steps again until you get it to where you want it.

Mike

Chienworks wrote on 8/20/2007, 10:58 AM

Turning off resampling will help make hitting exactly frame boundries less critical. It may introduce some cadence issues, but if the speedup is extreme then the cadence problems should be unnoticeable.

On the other hand, forcing resampling can cause some bit of blur and streaking which may help aid in the sensation of movement. Without these effects, speeding something up too fast may make it less apparent to the viewer that it's continuous motions. A series of crisp clear images that go by too fast may become disjointed and perceived as separate images rather than a speeded up version of a continuous scene.

The point at which the perception changes varies from person to person. About the only way to know which is better is to try it both ways, and have several people look at both versions and compare their comments.

farss wrote on 8/20/2007, 2:25 PM

I wonder if rendering out with a lot of motion blur first would aid the illusion?
I'd completely forgotten about the MB issue!
Must check out our SI-2K, I recall it'll do undercrank with a very slow shutter speed. I ignored that feature completely but now I think I understand what it's there for.

Peter Vred wrote on 9/4/2007, 7:18 AM

Thanks for all your help guys...I figured out the double render process which worked well. I'm at 70 seconds now.

A have to go back and make a correction or two and add a soundtrack now,
so I will try your other suggestions.

Also...is there a way to show a "time lapse clock" in the video, showing the actual time passing ?

This will make it more effective for my use: Time lapse of tearing down our live sound setup.
http://www.studio9music.com/video/Teardown.wmv

AlanC wrote on 9/4/2007, 9:03 AM

Peter, that's a broken link.

Chienworks wrote on 9/4/2007, 10:24 AM

You can add the timecode effect to the original event before speeding it up, render it to a new same-speed file with the timecode displayed, and then use that version for the speed increase.

This will count from 0. If you want to show the actual time of day i don't see any really good way to do that except maybe add the timecode effect to the track rather than the event, then slide the event down the timeline as many hours as necessary to have it start at the correct time of day. You can then render just this section of the timeline.