Forced Film and Pulldown?

[HockeyStick]

Hi everyone,
Since a couple of guides are not clear about that, i have a question about pulldown.
I'm doing all the steps in NTSC.
Now, in DVD2AVI, in the preview tab, it shows progressive/NTSC/Film and a percentage(sometimes not). So i perform always FORCED FILM. Is it necessary to do the pulldown step when forced film was activate?
I think 3:2 pulldown put a "flag" to tell the player to play at 29.97, so wy do forced film(29.97 to 23.976) if the movie is already at 29.97 at the beginning? And exactly when to perform this pulldown? (with bbMPEG at the end??)
Thanks,
(i know, it's a newbie question...) :rolleyes:

[Kedirekin]

Assume we start with DVD that is FILM 98%.

98% of this DVD is encoded at 23.97 fps. That 98% has RFF/TFF flags in the mpeg stream that tell the player to repeat fields (and what order to play them in). Thus, the 23.97 fps mpeg stream is converted to 29.97 fps during playback.

The other 2% is encoded at 29.97 fps and has no RFF/TFF flags (because it needs none).

Now you do DVD2AVI with Force Film on. Force Film tells DVD2AVI to ignore the RFF/TFF flags in the 98%, and therefore it frame-serves the 23.97 fps stream.

In the other 2%, DVD2AVI discards frames to maintain a consistent framerate.

When you encode from a d2v with Force Film set, the resulting encode is at 23.97 fps. You need to apply pulldown to insert new RFF/TFF flags so that the stream will be converted to 29.97 fps on playback.

One point of clarification - pulldown inserts many RFF/TFF flags in the stream (12 of each in each second of video I believe).

[HockeyStick]

Thanks for the explanation,
I appreciate.
HStick

[ppera2]

Hmmm...

Why making force film and then 3:2 pulldown ???
And with so mixed source ?

I think that 'cause you work in NTSC you should simple uncheck Force Film and make 29.97 fps mpeg video.

[w00d]

You are reencoding the video, so it must be in native FILM or you will get problems.

[adam]

Not to mention that encoding in ntscfilm with the pulldown flags saves you an extra %20 of your bitrate.