How to double frame number keeping same duration?

[Pierre Jasmin]

Steve,

Premiere: It might work taking the 18 FPS in an 18 FPS sequence, doing Twixtor 75% then drop that in a 30 FPS sequence and apply Premiere Speed 133.333% (1/.75) to that clip in the main sequence.. minus the fact that the main sequence will be one frame off (will have 2 times the first frame at the begining). Let me check all this monday.

Pierre

[Pierre Jasmin]

Steve,

Made a new project

https://www.revisioneffects.com/bugreports/prem/Copied_18_to_24_001.zip

You actually in Premiere need to do two nesting down for this (unlike AE)
1) 18 FPS: You need to pad the movie somehow so it’s more than 1/3 longer to extend the duration (in frames).
2) 18 FPS: Then you drop 1) into another sequence, apply Twixtor there 75%
3) 24 FPS: Drop 2) in there, keep current settings, apply speed 133.333%
You will see I tried to cut the first frame and slide it back to 0 as Premiere has a problem with it’s speed math when frame rate is different.
Because of that I would be careful about audio to make sure you are not a frame off audio wise (or worse) doing all this

Will have Lori do a tutorial on FPS conversion in Premiere this summer… 🙂

Pierre

[Steve Cohen]

Thanks Pierre, that worked. No idea why — it seems counter-intuitive that changing the speed to 133% with PP’s tools would actually make Twixtor do something, but it did the trick.

I had a problem with the first frame, too. It’s the first frame of a fade in and it bumped — no smooth fade. I think I need to apply the fade to the last sequence in the chain.

Thanks again —
Steve

[Steve Cohen]

Pierre,

Now that I’ve got the workflow issues sorted out, I have a question about artifacts. I’m using Twixtor on old 8mm movies that I’ve had transferred as HD TIFF sequences. Most are 18 fps in color with reasonably good exposure. This stuff converts to 24 nicely and it really improves the sense of reality. 18 looks like a silent movie. 24 looks ‘real’.

But I have a couple of rolls shot in B&W at 12 fps in a theater. Converting this to 24 is more problematic. When there is clear, sharp foreground action all is well. But when there are large expanses of underexposed, undefined grainy grey or black, Twixtor turns the grain into what looks like shimmering, moving jello. I’ve fooled with the settings and haven’t been able to get rid of it. Do you have any suggestions?

Thanks,
Steve

[Pierre Jasmin]

Yes in constant areas with heavy film grain twixtor will sort of cluster the noise
You might need some denoising before Twixtor
If you want to denoise just the motion tracking source, the ALT track source is there for that
To avoid another nested sequence, you maybe can instead apply a denoising tool like DE:Noise in the nested comp/sequence *nested 2* in earlier project parlance, and then copy the original video track turned off over it in sequence where twixtor is applied in *nested 1* and use that as “Color Source” – making sure the first frames are aligned.

Pierre

[Steve Cohen]

I tried De:Noise quite a while ago and thought it only softened this material. It’s really grainy — 8mm original. Not even Super-8. Attaching a sample. ‘

grainyblackandwhite.png

Steve

[Pierre Jasmin]

I suggested denoising a clip for the motion estimation part (using ALT Motion Source) and maintain the original movie as Color Source to interpolate frames. This way the grain will remain there but the motion calculated from the smoothed source will not clusted in heavy grain areas.

Alt Motion Source: This setting is designed to help you provide an alternate clip to use for tracking.

[Steve Cohen]

Pierre,
I’ve been experimenting with this all weekend and haven’t had much luck.

This time I’m in PP. The material looks like the sample frame I uploaded — B&W, running at 12 fps. To avoid the double nest, I an interpreting the source footage as 24 fps, cutting it into a 24 fps sequence and then applying Twixtor and setting it to 50% speed. This works well, but produces jello-grain artifacts in some scenes.

To test De:Noise, I created a new sequence with two video layers. First layer (v1) has Twixtor+DeNoise, Second layer (v2) has Twixtor alone with Alternate Motion Source set to V1. I’ve experimented with different amounts of noise reduction. Latest experiment has the least I’ve tried: Spatial Radius=4/Spatial Threshold=25, Temporal turned off (Process Mode=none). But still, the resulting file has what looks like blended frames rather than Twixtored, optical flow frames — as if every other frame is a little dissolve of the adjacent frames.

Do you have any suggestions? What am I doing wrong?

Many thanks,
Steve

[Pierre Jasmin]

Steve,

12 FPS is hard – You can try turning Motion Sensitivity way down like 30%

Anyhow, at this point if possible the best would be to send a project with footage to techsupport @ revisionfx dot com…

If the content is too large for an email, you can use the Contact form it will return an FTP zone login area

Pierre