What is 23.976 fps and NTSC 29.976?

[Beautiful Alone]

What's the difference? how do i tell if the DVD movie is 23.976 fps or NTSC 29.976? It said on one of the guides to enable to regular NTSC 29.976 with dvd2avi. Whats the point of doing so.

[Conquest10]

most dvds are 23.97 with 3:2 pulldown. if you encode them at 29.97 you might get jerky playback. so its better to keep the 23 with 3:2 pulldown.

[txpharoah]

Ditto on what GUMBY said....

Also....

Most movies are 24fps (23.976) NTSCfilm. Most tv shows and made-for-video discs are 29.97. Those are guidelines.

Opening the MPEG file in TMPGenc and be sure settings are not locked. They usually switch to match source. Easiest way for me, though I'm sure there are others.

[adam]

Well, you can't use TMPGenc to determine fps for NTSC encoded Vobs though because it will always report it as 29.97fps. Either it actually is 29.97fps or it will parse the pulldown flags and still report it as 29.97fps even though it is encoded at 23.976fps.

Here is the basic process for converting NTSC DVDs to either VCD, SVCD, or DVD...and this should be covered in any decent guide...

Open your vobs in dvd2avi and drag the slider about 1/3 of the way into it and hit the start point button ( it looks like a [ ). (opening logo's are almost always 29.976fps so they should be ignored.) Hit options/preview and check to see what % film it reports. If it reports 95% or higher film than that means your movie is encoded in ntscfilm (23.976fps) and uses 3:2 pulldown flags to telecine the movie to 29.976fps as it plays. With the exception of anime and tv source dvds (friends episodes etc...) almost all commercial DVDs will be encoded like this. In these instances, turn forced film on, and in your encoder set the output fps to 23.976fps. If making a SVCD or DVD make sure to also apply the 3:2 pulldown flag.

There are numerous reasons why one would want to encode in 23.976fps as opposed to encoding in 29.97fps, and I have literally posted them about 100 times. If you would like to know them just do a forum search.

If dvd2avi reports the vob as being anything other than 95% or higher then you MUST turn OFF forced film. This will export your movie as 29.97fps. From there you have two options. You can either encode at 29.97fps interlaced and suffer some quality loss, or you can attempt to do an Inverse Telecine, which will give you back your 23.976fps that your source hopefully started at. In order to do an IVTC you must first check your footage to see how it was telecined, if at all. To do so follow these suggestions... http://www.doom9.org/ivtc-tut.htm

If IVTC'ing is possible then the best method is to use decomb through avisynth. The syntax you will use will depend on how your source was telecined. From my experience, those few movies that are stored as NTSC (29.97fps) have undergone a standard 3:2 telecine, and thus are easy to inverse. This also seems to apply to the extra's on NTSC DVDs as well. So basically, DVDs are pretty easy sources to work with.

If IVTC is not possible then are stuck encoding at 29.97fps. In my opinion, you should only do this as a last resort.