ADOBE AFTER EFFECTS: Forum Expressions Tutorials Creative Cloud

Can this be fixed at this stage

COW Forums : Adobe After Effects

<< PREVIOUS   •   FAQ   •   VIEW ALL   •   PRINT   •   NEXT >>
darren behan
Can this be fixed at this stage
on Aug 14, 2016 at 3:18:45 pm

Hello All,

I could really do with some of your expertise with the following issue. We are prepping our film for festival for end of month. I just got done colour grading when I noticed there was a judder in the footage. We discovered this was due to the original canon files being compressed to 24 fps when they were 25 fps. The film was edited with this compressed footage in FCP and sent to me. I never noticed the disparity until I finished the render. I have tried to alter the frame rate in composition settings but to no avail. Please please please can we fix this at this stage instead of going back to original files. The technical issues are beyond my abilities so any help with this would be greatly appreciated. Many thanks in advance. Kindest Regards, D.Behan


Return to posts index

Kalle Kannisto
Re: Can this be fixed at this stage
on Aug 14, 2016 at 5:39:41 pm

Is the resulting visual problem skipping one frame each second?

If so, my wildly experimental and untested idea (I hope someone has a better one) would be to make an expression that time remaps that one frame to run at 50% speed while all others run at normal speed and using Pixel motion blend to create the in-between frame for that one-frame section that runs at 50% speed. You would use the original audio track, just recreate that one missing frame. I don't know if it would work, but in theory, it might.

If that is not the problem in the footage, please describe what it is or provide a short clip for us to see.

Kalleheikki Kannisto
Senior Graphic Designer


Return to posts index

darren behan
Re: Can this be fixed at this stage
on Aug 15, 2016 at 6:57:11 am

Thank You Kalle for your swift reply. I believe you are right here. The compression of the footage from 25fps to 24fps prior to editing the film obviously caused the lag. I am now dealing with a completed film with one frame missing every second as you describe. The expression idea seems like a very good suggestion. I am not sure how to input this so any help would be good. Unfortunately the sound files all match this new lagging footage. Thanks again.


Return to posts index


Kalle Kannisto
Re: Can this be fixed at this stage
on Aug 15, 2016 at 8:05:34 am
Last Edited By Kalle Kannisto on Aug 15, 2016 at 8:14:32 am

Hi Darren. Here's what I could come up with. I made a project that simulates the problem by rendering a 25-fps animation then encoding it into 24-fps. This gave me a piece of footage that skips one frame per second at the end of each second.

Then I imported that faulty piece of footage, interpreted it to 25 fps (important!) and applied time remapping. Then added a piece of code to count the frames so that it went 0 through 23, then added a frame 23.5 before going to frame 24, and repeat this each second. I turned on pixel motion frame blending for the layer and the comp and AE automatically created an interpolated frame for the "23.5" frame. For some reason the interpolated frame looks better when I make the time remapping value 23.6, don't know why, but that's what I finally set it at.

So that would be the basic fix. There is bound to be another set of problems, the first one being that you don't want to interpolate over a cut, so I added a control layer with a checkbox which, when disabled, allows to switch the effect off when the 23.6 frame happens to fall on a cut. You can keyframe the checkbox off for such instances.

The next foreseeable problem is that the missing frame may not always be between frames 23 and 24. That depends on whether the 25-to-24 fps conversion took place before or after editing. If it was done pre-edit, the placement will vary for every cut, if it was done post-edit, this method could work (fingers crossed).

Edit: Ok, so I reread your message and it was done prior to editing... I'll see if I can figure out a way to add a frame offset slider there.

10413_24to25fpsfix.aep.zip

Kalleheikki Kannisto
Senior Graphic Designer


Return to posts index

Kalle Kannisto
Re: Can this be fixed at this stage
on Aug 15, 2016 at 8:48:32 am
Last Edited By Kalle Kannisto on Aug 15, 2016 at 8:51:05 am

Here's the project with the addition of selecting the frame number that needs to be fixed. Hold keyframe the "Fix Frame Number" value for each cut to correspond with the frame number that jumps, i.e the frame number (0-24) of the first of the pair of repeated frames.

10414_24to25fpsfixframenumber.aep.zip

See if that works for you. The important requisites are:

- The new comp is 25 fps
- The imported 24 fps footage has been interpreted as 25 fps in the project panel
- Time remapping has been enabled for the layer
- Pixel Motion has been selected for frame blending
- Frame Blending has been enabled for layer and for comp

Output video only and use the audio from the original edit.

Kalleheikki Kannisto
Senior Graphic Designer


Return to posts index

darren behan
Re: Can this be fixed at this stage
on Aug 15, 2016 at 9:55:32 am

Hi Kalle,
You are an absolute gentleman, and once again your swift reply is much appreciated. You are obviously very passionate about what you do. Your knowledge on this technical nightmare I find myself in, is possibly beyond my scope. I will give it my best based on your feedback. Thanks again. I will keep you posted.
Regards, Darren


Return to posts index


Kalle Kannisto
Re: Can this be fixed at this stage
on Aug 15, 2016 at 5:57:33 pm

Let me know if you can't figure something out, or if I need to clarify something.

Obviously the proper handling will be to fix the footage and run through the edit and color correction steps again. It is quite possible that that route is less of a hassle than you think.

Kalleheikki Kannisto
Senior Graphic Designer


Return to posts index

Chris Wright
Re: Can this be fixed at this stage
on Aug 15, 2016 at 1:16:30 pm

i haven't converted it into your project, but you could use my cut detector code, similar to magnum edit detectors to auto detect the cuts in the footage.


https://f1.creativecow.net/10063/ae-custom-5050-opacity-frame-blend-with-au...


Return to posts index

darren behan
Re: Can this be fixed at this stage
on Aug 15, 2016 at 7:27:37 pm

I will give it a go but I think Kalle may be right. At this stage I think it's best to re-edit and regrade. We won't make that mistake again. Thank yo so much again for your expertise and input. I hope I can repay some time.


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]