Thanks for the full episode and for the additional information about the files. I think that the next step is to find something other than the Elgato to capture these because it seems to be creating some abnormality in the header (and because there must be a better way).

Frame rate mode                          : Constant
Frame rate                               : 29.970 (29970/1000) FPS
Original frame rate                      : 29.970 (30000/1001) FPS

The conversion from 25fps to 29.97fps is being achieved by duplicating every fifth frame – and, I think, a frame every 1001 frames (or not): the abnormality in the header makes it difficult to tell exactly what frame-rate the Elgato wants this to be. That’s quite common, and usually one uses TDecimate(Mode=2,Rate=25) to restore the video to 25fps, but in this case, it returns a non-standard rate: 25.0005fps. I tried to account for the abnormality in the header, but it didn’t make any practical difference to the output.

To do what I did, install AviSynth (the latest non-MT 32-bit version) and FFMS.

FFVideoSource("My Great Game - OilRig - 2016-09-04 21-40-20.mp4")
TDecimate(Mode=2,Rate=25)

But as I said, it would be better to find another way to capture, one that enables you to stay in 25fps. Nonetheless, HCenc seems to accept the input for DVD, even at 25.00005fps. What is your intended delivery format?

EDIT:

TheStarSwitcher said:
SMALL SNIPPET FROM VHS CAPTURE (what I’m trying to aim for, these tapes are in an amazing 60p if this helps. It’s presented here in 30 from a basic capture):

I don’t understand how a tape can be 60p. As you say, the sample is 30i – when deinterlaced, it’s 60p.