DVD Rip Uneven Frame Pacing (VFR)

[gindeno]

Hi,
I'm looking at some DVD rips that are a hybrid of soft telecine and a few hard telecines.

The bits that I expect to be 24 fps are, however the frame pacing is odd:
Rather than 41ms/frame (or 41 42 42 42 due to integers) the two DVDs I have tried are encoded as
50 33 50 34 , averaging 24fps, but with uneven pacing.

Oddly it occurs even if I play a DVD with mpv bypassing any involvement of MakeMKV.

Does anyone know what is causing this, and if I can get a proper paced 24fps in the sections.
I can't set the entire video to a CFR 24p as there are moments of 30i.

Thanks!

[dcoke22]

Could you chop up the video into parts so that you could set the non 30 fps parts to a constant 24 fps? Then you could merge it all back together again.

[gindeno]

What I've ended up doing is with a python script:
Export the timestamps
Replace every occurance of 50 33 with 41 42 and every occurance of 50 34 with 42 42. This gets the proper pattern in place, and the length of the clip remains spot on.

Additonally this has allowed me to easily detect the 30i sections, so using a vapoursynth script I can deinterlace only the 30i sections. It's not 100% at getting every bit of combing, but it has worked so much better than any combing detection techniques I've tried.