Vegas and Slow-motion

[Robert James]

So, I've seen some amazingly smooth videos on Youtube and such (and on this forum) with slow-motion. When I do slow-mo shots on vegas they always seem to look tacky. For example, in this video the second shot of a cat (in this case the orange one looking up with the glasses on the table) is a slow-mo Vegas shot I am not happy with:

indieslidin' - Cats'n'Lions (Testing the IndiSlider mini) on Vimeo

Now, maybe I am doing slow-mo all wrong. I am just pulling the clip holding shift, I think, to slow the clip or speed it up.

Is this the right method?

[Edward Troxel]

I believe that would be holding CTRL instead of Shift. That is a shortcut method of changing the "Playback Rate" found in the properties. Depending on the version of Vegas you have, you can also change speeds using the Velocity Envelope.

[Gerald Webb]

When ever changing speeds of a clip in Vegas always right click and -disable resample. This will stop Vegas from using frame blending and giving you "ghosts" of every frame.
You have much more control over you slow mo if you use Velocity Envelope rather than just Control drag.
With velocity envelope you can apply points and curves to your speed changes,
however,
I dont think you can achieve the speed ramping that we all see on other clips with the velocity tools in Vegas,
Final Cut and Adobe Premiere have different tool sets that just seem to ramp up and down with better Bezier curves than what Vegas can produce.
At least thats my experience anyway, if anyone here knows of any plug ins or techniques to do them in Vegas please let me know.

[Robert James]

Originally Posted by Edward Troxel

I believe that would be holding CTRL instead of Shift. That is a shortcut method of changing the "Playback Rate" found in the properties. Depending on the version of Vegas you have, you can also change speeds using the Velocity Envelope.

Sorry, yes, it is CTRL.

I am using Vegas 10 Pro.
Where do I find Velocity Envelope and thanks, by the way, for the tip.

[Robert James]

Originally Posted by Gerald Webb

When ever changing speeds of a clip in Vegas always right click and -disable resample. This will stop Vegas from using frame blending and giving you "ghosts" of every frame.
You have much more control over you slow mo if you use Velocity Envelope rather than just Control drag.
With velocity envelope you can apply points and curves to your speed changes,
however,
I dont think you can achieve the speed ramping that we all see on other clips with the velocity tools in Vegas,
Final Cut and Adobe Premiere have different tool sets that just seem to ramp up and down with better Bezier curves than what Vegas can produce.
At least thats my experience anyway, if anyone here knows of any plug ins or techniques to do them in Vegas please let me know.

Thanks for the tips.
Yeah, those ghost frames is one of the things that was making me dislike the slow-mo.

I, too, would be interested in a plug-in for this effect.

[Jeff Harper]

As a general thing I find the quality of the original footage is the single largest factor in slow motion quality. If you're using a slow lens in low light, you'll see a less detail as you apply slow-motion, it just doesn't hold up.

I thought your footage looked fine. The cat footage you mentioned wasn't particularly bright, but still was about as good as you should expect. Slap on a faster lens or apply more light and drop your gain and you'll see a great iimprovement.


If you watch the video below and get past the dumb intro that is speeded up, you'll see most of the footage is 80% slowed down, which is pretty darned incredible. The shot of the girl running isn't so great, it breaks up toward the end of her clip pretty bad, but the pan I made was the cause of that. Trying to get good slow motion on a panned shot is going to be much more difficult than when your camera is fixed.

Ault Park in Cincinnati May 1, 2011 - assorted video clips shot with the Panasonic GH1 on Vimeo

[Edward Troxel]

Originally Posted by Robert James

Where do I find Velocity Envelope and thanks, by the way, for the tip.

Right-click the event, choose Insert/remove envelope, and then choose Velocity

[Jordan Brindle]

Hi Robert, your clip looked fine to me. I think with slow-mo you're never going to achieve those liquidy smooth results unless you're kit and situation is completely geared towards that effect. Like Jeff said, altering your camera settings and lens, as well as improving lighting would help greatly.

[Ian Stark]

If you have lots of money to spend on this you may consider looking at Twixtor RE:Vision Effects, Inc. : Products: Twixtor

There is an OFX version and I have installed and successfully used the demo. Vegas is not stated as being a supported platform but for my limited experiments it worked just fine (for 'experiments' read 'playing around'). Have a look at their gallery - very impressive.

But I say it again - not cheap.

I echo Jeff's comment about the quality of the footage. The more work the camera does, the less interpreting the software needs to do.

[Sean Seah]

The official vegas twixor would be launched in Jul 11. Hopefully the price would not cst as much as Vegas itself!

[Mike Dulay]

Originally Posted by Robert James

Sorry, yes, it is CTRL.

I am using Vegas 10 Pro.
Where do I find Velocity Envelope and thanks, by the way, for the tip.

Insert -> Video Envelopes -> Event Velocity. It's a bit tricky when you pull it down so does the end of clip marker. Shooting at 60i then converting to half-resolution 60p can get you some really nice slow motion.

Primitive But Effective: Slowmo and Speed Up Effect 300-style

[Ian Stark]

If you right click on an envelope node you can type in a precise value which helps prevent dragging the wrong thing (like when you also have a fade to colour envelope on the same track - it completely masks the velocity envelope when both are at default values!).

In addition to the envelope, Vegas gives three preset values: 300% increase (i.e. triple speed), 100%, i.e. normal speed, and -100% increase, i.e. in reverse at normal speed. As an aside, I don't understand why that last one as a preset, as there is already a reverse function, found by right clicking the clip. Would it not be much more useful to give you a 0% preset, i.e. static?

[Edward Troxel]

Ian, it's there because that was the ONLY way to reverse a clip until a few versions back. Right-click - Reverse was added a few years ago but before that you HAD to use the Velocity Envelope to reverse a clip. In fact, I've had to explain many times the proper way to reverse a clip using the Velocity Envelope because you need to "start at the end" since you're going to go BACKWARDS - which is sometimes a difficult concept to get across. Right-click - Reverse really simplified that when it became available.

[David Jimerson]

There SHOULD be a 0% preset; I've asked for one for years.

Robert, also keep in mind that there's a relationship between your footage frame rate, your project frame rate, and the percentage at which you slow things down.

You will get best results when you match up a motion sample to a whole-number frame on the timeline. You figure this out by dividing the timeline frame rate by the footage frame rate, or just go to 50% if they match.

So, if you shoot at 60i and cut on a 60i or 60p timeline, your best result will be to slow to 50% -- because then, each of the 60 motion samples (each 60i field is a different sample, a different position in the frame) will line up exactly with a frame line on the timeline.

Then, when Vegas interpolates the frame, it's not mixing frames together; it's just filling in the rest. Or, in the case of 60p, it's just repeating the same frame.

So, you will get a lot less motion artifacting.

This is also true if you shoot 60i and slow it down to 50% in a 30p project -- each 60i field, each motion sample, then lines up perfectly with each 30p frame line. Or 60p -- each 60p frame lines up with a 30p frame -- the result will be sharp and glass-smooth.

Or, if you have a 24p project and you want to have good slow motion, shoot 60i or 60p and slow the footage down to 40% on the 24p timeline. All of the motion samples then line up with the 24p frames on the line. The result is smooth, artifact-free slow motion. The math also lets you slow down 30p to 80% on a 24p timeline, giving you a more moderate, but smooth, slo-mo.

When you do any of this, click "disable resample" in the clip properties.

Mismatching the math will necessarily lead to resampling and can lead to bad artifacting. Software like Twixtor can give you good results, but using Vegas's tools, it's usually best to stick with the math -- frame rate of project/frame rate of footage. (24/60 = .4; 30/60 = .5, etc. Slowing any frame rate to .5 on a timeline of the same frame rate will work, too.)

[Ian Stark]

Edward: Yes, of course. I recall that now. (Still want that 0% preset though! Or perhaps a 'freeze at this point' function like right click-reverse).