Vdub IVCT on interlaced material not so effective?

[Enchanter]

I've been trying to use Virtual/Nandub's built-in IVCT feature on NTSC DVDs, to little success. I was thinking that I could just load up this feature and do away with the Deinterlace filter. However, interlacing effects are still obvious.

Is there any way I could do a proper IVCT so that I won't have to load up any deinterlacing filter? A part of the reason is that I'm interested in lowering the video framerate to 24, from 30. I've not had any synch. problem doing this, so this is a good thing.

[Enchanter]

Alright...

I tried performing IVCT using TMPGEnc and the preview looks absolutely fabulous! No interlacing artifacts at all (for my test vob anyway). I saved the project (.tpr) and made the fake avi using vFAPI.

Now, here's where the problem arises. The encoding speed is grinding slow (25% of the usual speed). Has anyone experimented with this before and does the same thing happen? I'm just wondering if it's my fault or if this is what is supposed to be.