Jerky zoom-out: how to smooth out?

megabit wrote on 10/5/2014, 12:32 PM

I have a 2 minute fragment in my video where - zooming slowly out - I got unacceptably jerky movement. Theoretically it could be rectified as the clip is full HD and planned delivery - DVD, so I could use crop, but adopting the right keyframes and transition speed changes to counteract the bad zoom-out is beyond my means.

Any suggestions please as to the best semi-automated method? Perhaps some stabilization plug-in or external application could take care of zoom-only movement? Please help;

Piotr

Comments

farss wrote on 10/5/2014, 3:23 PM

If it's only the change in focal length that's the problem I'd start by trying adding Motion Blur in Vegas.

Failing that I'd go to AE.
If you can track two diagonally opposite points then the distance between them will let you calculate the effective magnification between frames and also the difference between the first and last frames. Then one can compute how much off each frame is from the ideal linear zoom and using that table of numbers create another table of numbers to apply a crop factor to each frame.
The Mocca people may have already developed a solution but that might cost you money. The basic tools that AE has and using expressions then it should be possible to solve this natively in AE. You might even find someone who has already done all the hard work for you.

Bob.

riredale wrote on 10/5/2014, 9:46 PM

DeShaker can do this. I don't know about the other stabilizing utilities.

megabit wrote on 10/6/2014, 3:00 AM

Bob,

Thanks for the answers - yes, Motion Blur does smooth it out but introduces too much smear in the cello player's hand wide movements. I'm so angry with myself - just forgot to the take my Manfrotto zoom controller to the set with me, and even though my hand is so shaky, in my stupidity I used it to zoom manually with the (too loose) EX1 zoom ring...

So the other proposal of yours is the only way to go if I want it fixed; you mention AE which I haven't got or know how to use - isn't this method viable with Vegas? Could you please elaborate on how you would try to adopt it, if possible at all?

Thanks Bob

Piotr

farss wrote on 10/6/2014, 3:37 AM

Piotr,
If Deshaker can do it I'd suggest going with that and it's free.

What I was proposing doing in AE is what Deshaker does for you anyway, I just wasn't aware it could handle fixing a bad zoom but it can. The Log File that it produces would also allow you to manually tweak the results from the motion tracking pass before you run the stabilization pass.

Sorry I'm no Deshaker guru but there are a few here. I have used Deshaker many years ago it does work very well and isn't half as difficult to use as the instructions suggest.

Bob.

megabit wrote on 10/6/2014, 4:31 AM

Bob, I did try both Mercalli V4 SEL trial and the New Deshaker; Mercalli is not good enough in smoothing zoom only imo. As to Deshaker, it's probably myself who is not good enough in using it - tried just the default settings, and the results are not good, either :(

Cheers

Piotr

farss wrote on 10/6/2014, 5:32 AM

When you tried Deshaker in what way were the results not very good?

My concern would be that a jerky zoom could introduce natural motion radial blur and that you'll never fix but before we pronounce all hope lost you really need to go through the worst part frame by frame for some forensic analysis.

Bob.

John222 wrote on 10/6/2014, 5:33 AM

Have you tried making a velocity envelope for that clip and manually keying the speed curve to even out the zoom? Not the perfect solution, but it should make a big improvement.

megabit wrote on 10/6/2014, 7:13 AM

Not an option - it's a classical music video; any change in speed and I have tempo or synchro probs.

Piotr

TeetimeNC wrote on 10/6/2014, 7:49 AM

Piotr, I have had good luck with Prodad's stabilizer on similar zoom problem footage. Any chance you could render out the problem segment and upload it to dropbox so we can give it a try?

/jerry

johnmeyer wrote on 10/6/2014, 10:18 AM

Full-featured motion stabilization can fix this. The de-featured version bundled with Vegas cannot.

Perhaps you can upload a high-quality version of the offending zoom and let someone here fix it. Alternatively, you might be able to download the full version of Mercalli and use that.

megabit wrote on 10/7/2014, 5:01 AM

Thank you guys so much for your generosity; before I take advantage of them I'd prefer to try and fix it myself :)

I indeed downloaded the demo version of Mercalli SAL V3, but am not very successful with it so far. The problem is probably that it's a "mixed up" camera type problem; the camera was on tripod so the only motion I'd like to stabilize is zoom. However - no matter which position I put the zoom slider at - the results are even worse than original :(

Could you please give me some hints as to the potentially settings? One of the scenes is zoom only, the other - slow panning with zoom (only zoom is jerky).

TIA

Piotr

amendegw wrote on 10/7/2014, 6:26 AM

Piotr,

You might try experimenting with each of the various "camera" settings - then use the sliders. The following image is from Mercalli V2.1. Guessing it's the same in V3.

...Jerry

TeetimeNC wrote on 10/7/2014, 9:54 AM

Amendegw's suggestion is a good one. Also, I've found glide camera to be a good starting preset for jerky zoom.

/jerry