Frame Rate in Gordian Knot

[Cactus Kid]

All the guides for Gordian Knot say to rip a dvd to avi using a frame rate of 23 frames per second. When I used 23 fps, most of my rips were jerky and did not flow properly. I then ripped them all at 29.97 fps and everything seems OK. Why do all the guides claim to only do it in 23 fps? Am I going to run into problems down the road with these rips?

BTW, this forum is amazing!

[killingspree]

pls give us some details about the movie / DVD you are ripping!

kr
steVe

[jggimi]

Welcome, Cactus; let me try to help:

Briefly, 35mm film is projected at 24 fps.

To make PAL videos from such film, the videographer merely speeds it up to 25 fps, which shortens the movie by 4%.

To make NTSC videos, they use a process called Telecining. This somewhat complicated process slows down the 24 frames ever so slightly, and then creates additional frames, ending up with a 29.97 fps video.

Those extra frames consume space in an AVI file, so we typically remove them from Telecined movies. This process is called Inverse Telecine, or IVTC for short, and it leaves you with a video that is 23.976 fps. But, this is only done on videos that were originally Telecined.

In GK, there are two methods for IVTC:[list=1]
Force FILM in DGIndex/DVD2AVI
IVTC filters inside the AviSynth script (.avs file)[/list=1] For much more information, see the IVTC tutorial at www.doom9.org/ivtc-tut.htm.