digitalFAQ.com Forum - Deinterlacing already captured footage

Hello,

I have captured my NTSC 8mm tapes as well as my VHS-C PAL tapes using virtualdub (Lagarith) and now I am trying to encode them to mp4 using avidemux.
I have analyzed the captured file and determined it to be interlaced because I can see the combing effect. In avidemux's x264 settings, there is the "Interlaced" checkbox that I am assuming I have to check because the source is interlaced. When I check the box and select TFF, the output seems sped up (not really sped up but it just looks that way) in VLC when its "Deinterlace" option is set to auto or on. However, when Deinterlace is set to off in VLC, it looks like the master copy (looks normal).
1) Why is this the case?

Also when the output MP4 file is displayed on TV (Sony A9G) it looks sped up just like on PC with VLC's Deinterlace option set to auto or on and there's no setting for toggling deinterlacing on the TV.
I was under the impression that I should not deinterlace just for the heck of it because modern TVs do deinterlace interlaced videos on the fly.
When I do not check the "Interlaced" option in avidemux, the output mp4 looks fine on PC with VLC's deinterlace option set to auto or off and looks jerky when set to on.

2) Doesn't not checking the "Interlaced" option in avidemux mean avidemux is going to deinterlace the video? It seems to do so because mediainfo reports "progressive" on the output but I can still see the combing effect on the end result. The output in terms of combing effect is the same as the one with "Interlaced" checked. What am I missing here?

3) Am I correct to say that for viewing on TV I shouldn't deinterlace?

4) If I wanna view on a PC, should I deinterlace or use on the fly deinterlace like the one in VLC?

5) If I need to deinterlace for the scenarios I explained, what is the best software (+instructions) to do so? I've read that QTGMC is very good, but I had trouble setting up avisynth on Windows 10.

6) Select TFF or BFF?

Attached are 10s samples of the master, interlaced checked, and interlaced not checked videos for reference.

Thanks