Reduce noise on 100-year-old film

[jharvat]

I am currently working on restoring a 100-year-old silent film. I have managed to clean up a lot of the dust, dirt, bad edits, etc., but the level of graininess throughout is still a concern. I have read through the various threads here on noise reduction, but I am unclear on what the current best-practices are for reducing graininess but not losing detail. Which Shotcut filter(s) are best suited for reducing video noise with the least loss of detail? Recommendations for settings for the filter are very much appreciated.

My film is currently broken up into three clips (~ 20 minutes each). The clips are .mov files (ProRes) and, as might be expected, are in black and white. I would like to apply the filter to the entire clip but not sure how long an analyze step might take for a clip that long.

I’d like to stay within Shotcut but I do have access to ffmpeg - although I am absolutely lost on the fine points of syntax for those commands. All other recommendations are welcome!

Thanks!

[Austin]

There are tons of variables. How big is the grain? How sharp are “sharp” details? This prevents us from providing a direct answer.

The generic answer is to start with “Reduce Noise: Wavelet” and try the presets. If they get the clip in the ballpark you want, tweak it as necessary and it’s done.

If the grain is large, then Wavelet will assume the grain is intentional detail rather than noise. Try “Reduce Noise: HQDN3D” instead.

Neither of them require an analysis step. HQDN3D runs twice as fast as Wavelet on average.

Sounds like a fascinating project!

[jharvat]

Thanks for the quick reply, Austin! Yes, it has been an interesting and challenging project.

I will post a few frames tonight so you can actually see what I am talking about. My idea of grain and sharpness might be too subjective to be of much help.