filtering suggestions

[Selur]

No clue, what the 'best' is.
How I would approach such a source:

• throw Retinex at it (while moving it to the end of the filter order) to better see the problems
  
  
• check the interlacing flag (tff seems fine)
  
• crop what should be inactive borders of the video
  
• check whether the luma scaling is correctly signaled (pc vs. tv scale); seems fine
  

Due to the severance of the artifacts in this source (multiple times compressed, badly captured) and the general darkness of the source, I would think whether the source luma levels should be adjusted.
Then I would try how Deblocking and some other heavy filters (MCTemporalDenoise, BasicVSR++, SpotLess) influence the output.
Due to the bad shape of the source, there are no details any normal sharpener could emphasize.

Assuming you don't plan to change the luma levels (make the whole thing brighter), I would probably use different filters&co on dark and bright areas of the image (= use some luma masking when using filters).
For the chroma you can try using HQDN3D, set luma strength to 0 and just use the chroma denoising.

=> The only thing one can do with such a source is trying to reduce compression artifacts while trying to keep some of the existing details.


Cu Selur