Velocity > 300% ?

Kevmiami wrote on 3/25/2003, 8:15 AM
Good Morning,

I have a 40 minute sunset I want to squeeze to 5 - 7 minutes (so it will look like a time lapse sequence). After cropping, I will use it as a background for a Memorial Video, with masked photos appearing on top of the background, with an appropriate soundtrack.

What would be the "Best" way to compress; velocity envelope is limited to 300%. Should I render "base image" at 300% and then re-render again with additional velocity envelope and all other effects? Thanks for the advice, Kevin

Comments

Chienworks wrote on 3/25/2003, 8:34 AM
You can also set the playback rate to 4x either by Ctrl-squishing the clip or in Media Properties for the clip. Combined with the velocity envelope this will speed it up 12x. For anything faster than that you'll have to render and then continue speeding up the rendered clip.
TheHappyFriar wrote on 3/25/2003, 11:11 AM
I belive you can make/modify a script to export a movie (frames?) with every nth frame. Also, you could try re-capturing the footage with iuVCR from www.iulabs.com. It supports time lapse, and it will capture eigther DV or analog.

I just did the math (in my head and a piece of paper) If you take your 40 minutes video and speed it up to 200%, render, put in time line, render your new video at 200%, render, put in timeline, and render at 200% AGAIN you should have a video about 5 minutes in length. Here's how I figured it out:

40minutes = 72000 fames
5 minutes = 9000 frames

9000*8=72000
so how did i get 200% speed increase? x*x*x=8
x=2 (or 200% of 1 = 100%)
so.. 2*2*2=8 or 2^3. Now, this happened to work for this, so i don't know how it will work with different counts, so good luck!

ps: I tested out a 40second clip with this and got it down to about 5 seconds. Should work the same for 40 minutes to 5 minute.
GrizzlyIke wrote on 3/25/2003, 3:01 PM
Need some clarification. Does the velocity envelope refer to a true percentage or a "magnification" factor? Normally, 300% does not equal 3x! The formula would be "speed increase factor" = (1 + %age/100). My question then becomes: does a velocity envelope setting of 300% increase the speed by a factor of 4 (as standard convention would imply) or a factor of 3? If the former is correct, then Kevmiami could render his 40 minute clip to 10 minutes at 300%, then render the resulting 10-minute clip to 5 minutes at 100%. Using Chienworks' recommendation, combining a 4x playback rate with a 300% velocity envelope should result in a 16x speed-up. With this approach a 4x playback rate and a 100% velocity envelope, or a 2x playback rate and a 300% velocity envelope should get Kevmiami the 8x speed increase he is looking for. If 300% means 3x then the first render at 300% will result in a 13.3-minute clip which will need to be rendered again at 267% to get 5 minutes, or try 200% ve and 4x playback. Now I'm confused!
Hope this helps.
Grizzly Ike.
P.S. To TheHappyFriar - come on up to Niagara Falls for your winter shoots.
Chienworks wrote on 3/25/2003, 3:15 PM
300% means 300% (3x) of the original value, not a 300% increase. Without specifying that it's an increase, convention would indicate that it is "magnification".
TheHappyFriar wrote on 3/25/2003, 9:12 PM
Grizzly Ike, you live in Niagara Falls? Ontario or NY? I live right in the between Springville and Ellicotville. I've wanted to go up there with the video camera from work (DVCPro Camera) but I can't until I get my 'new' car! Them I plan to show up there and get footage to put on TV! Now the snow's almost gone though. I might have to wait until next year to get some snow footage.
GrizzlyIke wrote on 3/27/2003, 9:02 AM
Chienworks - Thanks for clearing that up.
Grizzly Ike
GrizzlyIke wrote on 3/27/2003, 9:06 AM
Friar - New York. The falls can be quite spectacular in winter. But, I don't have a single clip of the falls to prove it! Guess you don't always appreciate what's in your backyard. Was born and raised here (long time ago) and never did get to visit prospect point!
Grizzly Ike
TheHappyFriar wrote on 3/28/2003, 7:02 AM
I just got a 1 hour 9 minute sunset out of the backdoor at work, and i'm hopefully getting to the falls soo. It would be cool to see timelapse of the falls, maybe with one of the boats going under. :) it'd be cooler if a barrol went over.