[MacDV] Re: 23.98 fps when using Cinematize or DVDxDV

[Aaron]

>Date: Tue, 10 Jan 2006 16:32:34 -0800
>From: "Dennis R. Cohen" <drcohen at mac.com>
>To: macdv at listserver.themacintoshguy.com
>Subject: [MacDV] Re: 23.98 fps when using Cinematize or DVDxDV
>Reply-To: "A place to discuss digital video on Macintosh." <macdv at listserver.themacintoshguy.com>
>
>On 1/10/06 at 5:46 PM, whoisquilty <whoisquilty at gmail.com> the following
>electronic message:
>
>>Hello -
>>
> >I keep getting Quicktime files with 23.98 FPS when I convert a DVD to
> >MOV with both Cinematize and DVDxDV. I'm trying to create a NTSC file
>>from the DVD. The frame is sized to 720x480. But the frame rate always
>>comes out to 23.98. I ripped the files using Mac The Ripper 2.6.6.
>>
>>Any ideas what would cause this?

I know nothing about Cinematize or DVDxDV, but I'll make an educated guess about what's going on:

If an NTSC DVD was created from a 24 fps movie, it really only contains ~24 fps, along with a code that tells the DVD player to create one extra frame for each four given ones. (Presumably, the DVD player uses 3:2 pulldown to create the extra frames, but I don't suppose it has to!) When a program is converting the DVD's MPEG-2 file to a MOV (or AVI or MPEG-4) file for displaying the movie with a computer, there's really no reason to put in the extra frames, so the file is created with a frame rate of ~24 fps, as in the original movie. (I'm not sure why it would be at 23.976 fps rather than 24 fps, although 23.976 fps is exactly 4/5 of the NTSC frame rate of 29.97 fps.)

(BTW, I'm curious why one would want to create a MOV file with a frame rate of ~30 fps if there really are only 24 frames per second in the original movie.)

>DVDxDV and Cinematize both default to encoding at what is called "NTSC
>Film" rate -- 23.976 fps.

Do they do this even when the DVD was made from original NTSC video with ~30 original frames per second? I doubt it, and would have a low opinion of a program that did that, unless it were creating images to be put back on film!

>If you check the frame rate of the VOB files
>ripped by MtR, you'll see they're still at 29.97 fps.

According to what indicator?

>DVDxDV refers to
>the as "3:2 Pulldown" -- you'll need to use DVDxDV Pro (or some other
>converter) to avoid the pulldown implementation.
>
>--
>Dennis R. Cohen

If I'm right here, the program's that are creating the  23.98 fps MOV files ARE avoiding "the pulldown implementation", since they aren't creating any extra frames!

BTW, I found a fairly good explanation of "3:2 Pulldown" at <http://www.dvdfile.com/news/special_report/production_a_z/3_2_pulldown.htm> and intend to reread it when I'm more wide awake. ;-)

 - Aaron