Order of Operations

[Eluthingol]

Hello all...
I am working on a project that involves:
--spot removal
--stabilizing
--degrain
--deflicker
--frame interpolation
--upscaling

Is there an order of preference? I think the big question is: interpolation before or after upscaling, but if there are other experienced opinions I would welcome reading them. Thanks!

Joe

[johnmeyer]

You should find some answers, as well as ideas for your own script, if you look at "VideoFred's" script in this thread over at doom9.org:

The power of Avisynth restoring old 8mm films

I started a branch of his script and posted a fairly recent version of that here:

John Meyer Film Restoration Script 2024

Order in my script:

Stabilizing
Deflicker
Spot Removal
Denoising
Sharpening
[Frame Interpolation] (I seldom do this because the results have artifacts)
Color Grading

[Eluthingol]

Thanks for the tip, John.

[VWestlife]

Just say no to frame interpolation. Leave the "slopification" of motion to the awful on-by-default presets built into modern TVs.

[lollo]

Just say no to frame interpolation. Leave the "slopification" of motion to the awful on-by-default presets built into modern TVs.

Except if you need to replace a corrupted frame

[johnmeyer]

I totally agree with Lollo that frame interpolation should definitely be used to replace bad frames.

I also agree about not using frame interpolation to turn movie film into video. It looks awful, and once you know what artifacts it creates, you can never watch the result without being totally distracted by broken legs, dancing picket fences, and weird morphs as people enter and leave a scene in the foreground.

Having said that, I have used it myself on a few projects that involved a lot of camera panning on 16 fps film. The problem is film "judder," an artifact that happens in your brain when the camera pans and, because your "persistence of vision" barely works at 24 fps, and breaks down completely at 16 fps, your mind sees the scene jumping and vibrating. So I did use it on this project:

1940 Flint Michigan Parade

It was 16mm 16 fps film, and the camera was constantly panning as the parade went by. You will still see all of the artifacts I mentioned above (wait for the breaking moose antlers at around the 1:39 mark), but I decided that having artifacts once every 10-15 seconds was better than the almost constant judder from the camera panning.

Most movies don't have such extensive panning and therefore the tradeoff of smoother motion isn't worth it.

[pandy]

operation like frame interpolation should be done with maximum possible resolution (and adequate parameters) - after downscaling you minimize errors (or in other words - you achieve higher subpixel precision) - if your goal is upscale then i would upscale more before frame interpolation and eventually downscale as the last step.

Btw if you can accept longer processing then upscaling can be done as first step almost always (exception is deinterlacing) - by upscaling you always increase subpixel precision and you can use finer settings (for example fractional range) - sometimes simpler filters with sufficiently high upscale can deliver more than good results.