Deinterlace NTSC without converting fps

[raeltheimperialaerosolkid]

Recently I could examine a NTSC DVD rip but I couldn't realize how the deinterlacing had been done. It was a normal .avi encoded in Xvid but it featured the framrate at 30fps instead of the classic 24fps. The deinterlacing operation had been really well done without showing artifact of any kind. Since the footage inside showed a lot of CGI that was really smoother than the same CGI I saw in another rip at 24fps of the same footage. I was wondering how could I made a good conversion from interlaced to progressive without "downgrading" from 30 to 24? I read through the guides but I could find the answer.

[Borbus]

You get 24fps after you IVTC it. You only do this if the source was a film. For TV sources, it hasn't been TC'd so it stays at 30fps. For a film, 24fps isn't a "downgrade" as this is how a film is made and shown in the cinema.