There is a thing called critical pan speed. The combination of movement, frame rate and retinal retention mean that any movement in the frame that falls in the range of critical speeds will judder. The way to reduce the problem is to shoot at higher frame rates. Unfortunately, higher frame rates mean less motion blur and we like to have motion blur so the footage looks more like a movie and less like a video.
If you are stuck with problematic footage that was shot at 24 (or any frame rate) you have two options. Change the timing of the shot, which may result in audio problems or unnatural action, or force some motion blur or use some software to generate extra frames to try and hide the problem. All you have to do to change the timing is change the interpretation of the footage (File>Interpret Footage>Main). Forcing motion blur can be done with CC Force Motion blur, but really good “new” frames can really only be generated with 3rd party software.
Twixtor is really good at interpolating extra frames. If you want more frames and you want the timing to stay the same then you have to increase the frame rate of the comp (sequence in Premiere Pro) and use something like Twixtor. Force Motion Blur will work when the frame rate for the footage and the comp are the same, but the results are not as good.
I hope this makes sense to you. The ASC handbook has had critical panning speed tables in it for a zillion years. If you don’t pay attention and check on the set it’s pretty easy to end up with shots that can’t really be fixed in a pleasing way.
Here are a couple of articles from the After Effects FAQ section of the Adobe Forum on avoiding and overcoming the problem:
I hope this helps.
Following are I think your options:
If you are dealing with unsync clip (no sound matching critical), you could interpret your footage to play at 23.976fps, and they will play a little faster at 29.97fps (duration will be shorter).
If you are editing with interlaced footage (kind of unusual these days other than for broadcast masters), then you could add pulldown during your AE export.
Otherwise you will have to recreate these missing frames one way or another… using a plugin like Twixtor...
I'm drawing a blank here. Tried a few solutions and haven't gotten the solution yet. I have some 23.976 footage that I'm using in a 29.97 sequence. I'd like to use optical flow to eliminate that judder frame that is present when putting 24p footage into 30p timelines. What's the way to get this done? I feel like I've done it before. Checking the frame blending box doesn't seem to fix it. I'm not changing the speed of the clip.
Thanks
