HELP !!!!!! Vegas causing footage to stagger

Deuceofspades

Deuceofspades

Veteran
PROBLEM:

Pans stagger very noticeably when clip speed is altered.

DETAILS:

whether using the velocy curve or simply using property options, speeding up or slowing down a pan is causing it to stagger in a very noticeable manner (as in not usable in a feature film).

Spent 3 hours trouble shooting last night: Cause of stagger is linked to selecting the "disable resample" radio button.

As you know, NOT selecting the "disable resample" radio button and keeping resample at it's default setting will cause the image to appear "ghosted". Also not useable in a feature film.

So damn if I do and damn if I don't???

HOW DO I SOLVE THIS VERY SERIOUS PROBLEM.

Stationary shots sped up or slowed down do not create any noticeable stagerring. Only Pans do. I have lots of pans in my film.

:badputer:


Please help/advise.




.
 
Faith, if you didn't shoot that footage at 60p, the software is always going to struggle to give you smooth footage on a pan. The software is guessing at the frames when you do a slowdown. If you shoot 60p, it has more data to work with.

Static shots look better because it's easy to guess where things should be from frame to frame. But pans... it's much harder.
 
How do I work around this? As you know I shoot at 24 fps.

BTW: Thank you soooo much for all your help yesterday Perrone. You rock.
 
Quick pans stutter at 24P anyway and they always have. (The correct term is "judder.") That's one of the many things that bug me about shooting at 24 frames per second. There is simply not enough temporal resolution to slow down 24P and have it do anything BUT judder. You do realize that the only reason that films are at 24 frames per second is that it is the slowest frame rate that filmakers could use and still give the effect of relatively fluid motion. There is nothing magical about 24P, the decision years ago to use 24P was purely economic. Film was (and is) expensive and they didn't want to run it any faster than absolutely necessary. Slowing it down any more from 24P is just asking for trouble. Filmakers "overcrank" their cameras and record at a faster frame rate when they want to do slow motion. For example, they shoot at 96 FPS and play it back at 24.

There is software that will do slow motion by creating new frames in between existing frames ("tween" frames) but I have never seen it work acceptably well. "Twixtor" was one, but I don't know if it's being sold anymore. Bottom line is that you made the artistic decision to shoot at 24P and one of the compromises of that decision is not being able to use slow motion. There is no practical way to solve your problem.
 
Last edited:
Optical Flow could probably get it done, and VirtualDub could too... but depending on the pan and the complexity of the frame, there may not be a a whole lot we can do.

Can you post the sequence in question on youtube or something so we can see it. Maybe post what it looks like normal, and then what it looks like slowed down?
 
John Cline said:
Quick pans stutter at 24P anyway and they always have. (The correct term is "judder.") That's one of the many things that bug me about shooting at 24 frames per second. There is simply not enough temporal resolution to slow down 24P and have it do anything BUT judder. You do realize that the only reason that films are at 24 frames per second is that it is the slowest frame rate that filmakers could use and still give the effect of relatively fluid motion. There is nothing magical about 24P, the decision years ago to use 24P was purely economic. Film was (and is) expensive and they didn't want to run it any faster than absolutely necessary. Slowing it down any more from 24P is just asking for trouble. Filmakers "overcrank" their cameras and record at a faster frame rate when they want to do slow motion. For example, they shoot at 96 FPS and play it back at 24.

There is software that will do slow motion by creating new frames in between existing frames ("tween" frames) but I have never seen it work acceptably well. "Twixtor" was one, but I don't know if it's being sold anymore. Bottom line is that you made the artistic decision to shoot at 24P and one of the compromises of that decision is not being able to use slow motion. There is no practical way to solve your problem.
Click to expand...

yes, I am well aware of all above LOL, and did overcrank the HVX200 anytime i planned to do slow mo

However, sometimes inn editing you make pacing decision after the fact and a velocity curve is a powerful and useful tool for that perfect timing.

I used slow mo in post all the time and it looks fine, but pans are another story, but then also note that I said that speeding the pan up makes it judder just as much (does that confirm or destroy your above theory LOL I'm not sure?...)
 
Deuceofspades said:
I used slow mo in post all the time and it looks fine, but pans are another story, but then also note that I said that speeding the pan up makes it judder just as much (does that confirm or destroy your above theory LOL I'm not sure?...)
Click to expand...

Everything John and Perrone said is spot on.

Assuming you want to do this all in post instead of re-shooting, you can't solve this in vegas alone.

As already mentioned, the "best" way is to shoot a higher fps, all the other approaches will have varying degress of problems

In post production , there are 3 general approaches when doing speed changes:

1) blend frames
2) duplicate frames
3) motion interpolation of new frames

Vegas can only do #1 and #2. The default behaviour is blend frames when you make speed changes, so everything is blurry (but still juddery). When you disable resample, it duplicates frames (very juddery) or option #2.

John referred to #3 , the side effects are long processing times and generation of new artifacts since the software attempts to interpolate new frames (as if you were shooting at a higher fps). The more motion and complex your scene, the more prone your footage is to artifact generation, and that's why Perrone suggested to have a look at the footage. Other software that can do #3 are avisynth (mflowfps), After Effects pixel motion, motion perfect, (a few others).

Bottom line is they all have issues.

If you want to see a comparison of the general methods, I've posted some sample clips here , and example of a 4x slowdown. They aren't pans like your footage, but they are just meant to illustrate the differences and problems between these methods in post. (You need to be able to view xvid compression to see these, or use a player like VLC which is multiplatform and includes all decoders necessary internally)

http://www.mediafire.com/?mkcnexhjewg
 
Last edited:
Can't create frames that don't exist... Well, you can, but they probably won't look so nice (e.g., stutter vs. interpolation ghosting, pick your poison).
 
Hal2 said:
Check this out http://www.youtube.com/watch?v=bVlhyqR1Xrg it's helped me a few times in your type of situation.
Click to expand...


Ooooo way cool :)...

I find that some of the pans even with altered speed, still look good, while others stagger immediately as soon as altered in the least bit.

I did finalize first half of the film and basically put those trouble clip back at normal speed, since a lot of alteration where so manute (say 110% instead of 100% speed)... It solved the problem of course. Clips that looked fine with altered speed I kept.

But now I am easger to try above method for some of the clip that I REALLY must have altered speed on... I'll let you know if it works good for me.

THANK YOU!
 
Deuceofspades said:
Ooooo way cool :)...

I find that some of the pans even with altered speed, still look good, while others stagger immediately as soon as altered in the least bit.

I did finalize first half of the film and basically put those trouble clip back at normal speed, since a lot of alteration where so manute (say 110% instead of 100% speed)... It solved the problem of course. Clips that looked fine with altered speed I kept.

But now I am easger to try above method for some of the clip that I REALLY must have altered speed on... I'll let you know if it works good for me.

THANK YOU!
Click to expand...

No problem, let us know if it helps....

I'm real amped to see how this thing turns out - let me know if I can be of any help!
 
You must log in or register to reply here.
Back
Top