NTSC and NTSC-Film????

[DaveJ]

hey i use smartripper to rip dvds on my harddrive then dvd2avi and tmpg to make vcds. when i use dvd2avi i see that most dvds that i rip are 23fps. so i should use ntsc film in tmpg right? does it really matter if i use ntsc with 29fps? is there a difference in quality? i would appreciate any helpful feed back. just one more question after my mpeg 2 trial ended in tmpg how can i make a svcd?

thanks
dave j

[tonyp12]

For NTSC FILM DVDs set "force film" in dvd2avi

Pretty sure only svcd/mpeg2 support "3:2 puldown when playback"

Select "23.976 (internally 29.7)"

Correct me if svcd do not support this flag (3:2)

[adam]

Well forced film will work on the vast majority of ntsc dvds but not all, and using it when you shouldnt will yield horrible results. Preview your movie in dvd2avi and let it get past the opening credits, better yet set your start point somewhere in the middle of the movie and then preview. If dvd2avi reports film, or %95 or higher film than use forced film. Then encode in 23.976fps and if you are making a DVD or SVCD than apply the 3:2 pulldown.

If dvd2avi reports anything else then disable forced film. Now you have the choice of either encoding at 29.97fps or possibly doing an inverse telecine if the source originated as film. Fortunately this situation rarely ever arises with dvds since almost all are stored progressively at 23.976fps and thus forced film will work perfectly. However, there are certain types of sources that are more likely to be stored at 29.97fps or be some sort of hybrid disk. Things such as concert dvds or even tv shows are examples where forced film won't work.

Yes there is a definite benfit to encoding ntsc material at 23.976fps as opposed to 29.97fps. The conversion from 23.976fps to 29.97fps adds new fields to the movie, and each of these fields require bits. So by encoding at 29.97fps your bitrate is being spread out over %20 more frames, and thus you lose %20 of your quality. When you encode in ntscfilm (23.976fps) it is stored at 23.976fps and the conversion to 29.97fps is done on the fly as it plays by the dvd player.

Basically, assuming a film source ntscfilm will be %20 higher quality than ntsc and it will also eliminate alot of encoding headaches since having progressive frames means you don't have to worry about all the problems that are inherant with interlaced frames.