3:2 selection in ffmpegX

[talisman]

What is the 3:2 set and undo options in ffmpegX's option panel suppose to do. Does this have to do with "pulldown" that I have read somewhere in this forum, and can anyone define what a pulldown as well as it's use in SVCD's

[incredible]

The Pulldown option lets encode you mpeg2 streams from NTSC FILM! sources so you can author and view DVDs & SVCDs from this source.
This means, if you get a NTSC film source for example a movie with 23.97 fps and you encode it directly to 29,97 fps (frames per second) your audio will be out of sync! cause the video track will play faster!

If you have a NTSC Film source with 23,97fps (check it in Quicktime, most DVIX movies play at 23,97fps!) and you want to author a SVCD of the DVIX movie you have to encode the avi in ffmpgx still at 23,97!!! NTSC FILM!!!! but also you have to check at options "3:2 Pulldown" so your DVD player will play the videotrack at its correct FPS.

If you check the encoded result m2v of ffmpgX in MPEG infoX you will see that this movie is recognised as a 29,97 NTSC! But if you open it in Quicktime (with the m2v read extension (not included normally in Quictime)) you can see 23,97fps this means everything is ok - recognised with 29,97fps and playback with 23,97 --- audio is in sync!

By the way it is a rise in quality to encode a movie to mpeg2 at it's original 23,97 with the same bitrate as 29,97 with the same bitrate cause within the bitrate you have a smaller amount of Frames to encode and so you have more bitrate for each picture! -- better quality
This is also mentioned in the PDF Documents of MPEG TELECINE of the DVDsp helpers homepage where you can download MPEG TELECINE (a standalone appl. wich also makes a 3:2 pulldown)

Markus

PS: Go to the site menue of this website upper left and choose "What is SVCD" there you can see at the NTSC requirements a link in the text called "3:2 Pulldown" which brings you to a site where 3:2 Pulldown is explained in a professional way!