Uncommon convertion: NTSC to NTSC film

[HDSN]

Hi all

I´d like to know if it is usual to convert a NTSC video to a NTSC film video, I have searched in the forum and I didn't find a thread related to it, most of them talk about conversion between NTSC and PAL.

Ok, why convert NTSC to NTSCfilm?
I think it is a way to put more video in a disk, right?

Since a NTSC film has less frames per second than a NTSC one, at the same bitrate and resolution, it will locate more information per frame, improving the image quality. A supposed worse quality due the lower number of frames in NTSC film will be conpensated with the 3:2 pulldown while playing.


So, if this theory is ok, what is the right way to change the fps from
29,97 to 23,976 ?

I have been trying to do that directly in TMPGEnc but the result is an
audio out of sync and a video with jerky movements.

Any tip is appreciated.

thnx

[Meteor]

What you are looking for is called Inverse Telecining. If your source material is pure interlaced, you're better off keeping it at 29.97 fps. But if the video have 3 progessive frames followed by 2 interlaced frames, you'll be able to restore the video back to 23.976 fps. If have something in between, you probably have a hybrid video or something badly telecined. Good luck on those.

You can inverse telecine with TMPGEnc or with AviSynth/VirtualDub with the proper filters.

Converting the framerate to 23.976 fps does not decrease the quality. It allows more bits to be allocated to each frame. The 2:3 pulldown does not compensate for a loss of quality. You are getting better quality with fewer frames. The pulldown allows progressive material to be displayed on an interlaced screen.