stupid question about framerate

[mberndt100]

what exactly is the 3:2 pulldown? I read the glossary but I'm still not sure what it is and when do I need to set it?

I have some XVID files that are 23.976 fps. I want to convert them to DVD using ffmpegX. Do I need to set the 3:2 thing?

Thanks.

[alph]

Where NTSC is the standard, such as North America, the standard DVD framerate is 29.97. This means that most of the standalone dvd players work best at that framerate. 3:2 pulldown is a technique by which frames are juggled around so that 23.97 fps plays as if it were 29.97. No frames are added or removed. That said, if your DVD player is NTSC, then you should use Pulldown.

Related to this, I've learnt from experience, is that if converting from PAL, ie 25fps, you tend to get better results if you convert to NTSC film (23,97) with Pulldown, than if you go directly to an NTSC framerate. The latter tends to cause more sync problems.

Cheers,
Alph

[mberndt100]

thanks--that was a clear and concise description--exactly what I was looking for!
Mike

[junkmalle]

NTSC video is 59.94 fields per second. That's all you have ever seen on a standard definition NTSC TV. You have never seen an entire frame.

3:2 pulldown is the creation of 59.94 fields per second from a 23.976 frame per second film source:

http://www.dvdfile.com/news/special_report/production_a_z/3_2_pulldown.htm

There are two ways of making a DVD from a progressive 23.976 frame per second source. You can leave the frames progressive at 23.976 and have the DVD player perform the pulldown as it plays the DVD. Or you can perform the 3:2 pulldown in software and encode 29.97 interlaced frames per second. The DVD player will then display each interlaced frame as two fields. In the end you will see exactly the same thing on your TV.

The former method is preferable though since fewer frames per second need to be encoded, and progressive encoding works better than interlaced encoding.