What is 2-3 pulldown, and how to correctly digitize Hollywood movies recorded on VHS tape 

Usually "Adaptive" setting works well enough when the cadence is strong. If the cadence is hard to detect, I prefer to deinterlace to 60p.

I don't know much about festivals, but technologies to transfer video to film existed since 1930s. There are different approaches and different ways to convert frame rate. Unless frame rates match, the result will be blurry and may show interlacing artefacts. For exaple, watch the official trailer for "Genghis Blues" and notice occasional combing and double images.

@@ConsumerDV Hi, if I take an SD camera footage and play it on a great screen. Then record the screen with a 4K camera. Would that work?

Depending on what your goal is. It won't have details of real 4K. If you want 4K that has high resolution but looks like VHS, shoot 4K and use a filter to give it more old school look. Another option is to use old tube camera but feed it into an HD recorder. It will be higher quality that crappy VHS, in fact many tube cameras can easily resolve 800 lines or more. And it will have characteristic tube appearance with trails.

@@ConsumerDV thank you so much

You do not need to do anything else. When you save the video, it will be encoded with 23.976 rate. On the bottom of Filters dialog box there is a checkbox "Show frame rates", enable it. If you reduce frame rate in IVTC filter, you will see the reduced rate in the filter chain.

@@ConsumerDV Thank you so much!

VHS as well as DVD is an interlaced "transport" so to speak. But it can carry progressive content. So, twenty or so years ago when reviewers used to test the quality of deinterlacing, they have different tests for "video" and "film" content. "Film" content usually comes at 24 fps for NTSC region and 25 fps for 50 Hz region, and proper deinterlacer should figure out the cadence and recover it to restore full vertical resolution and to avoid combing. This is what inverse telecine does. For native "video" content you need to deinterlace it into 50p or 60p depending on region. Modern computer players like VLC or Splash can deinterlace interlaced video rather well, so you don't see combing and you get all the 50 or 60 images per second. But for some reason RU-vid has never bothered with correct deinterlacing, which is why before uploading you should figure out what sort of content you are dealing with, and either deinterlace with frame doubling if it is "video", or remove the pulldown if it is "film". Some movies have unstable pulldown patterns, so it is easier just to deinterlace them as if they were "video", this is what cheap TV sets do. TL;DR: deinterlacing with frame doubling always works :) but IVTC will produce a slightly better result and a smaller file if you have "film" content. And now back to the original question: what if you wanted to keep interlacing. You certainly can do that, just do not use any deinterlacing filters. Unfortunately, depending on the codec and container, when you save file from VirtualDub, it does not always sets the flag that the video is interlaced, so it may throw off some players that refer to flags and do not analyze frame structure. Also, you need to preserve inerlacing if you plan to author a DVD. OTOH, VirtualDub does not output MPEG-2 needed for DVD, so you will need another program to produce it, and most authoring programs will automatically convert your 24p video into interlaced MPEG-2 with progressive flags.

@@ConsumerDV Excellent answer, thank you for taking your time on it.