24p -- 29.97i in AE

Question

Can After Effects convert a 1080p23.976 frame rate to 29.97p or 60i? I want to convert the 1080p23.976 for broadcast. Can AE introduce the pulldown to do this? Please note that I'm using CS4.

Answer 1

When using his converter to (try to) go from 23.976p to 29.92p, the video ends up being 24 seconds long instead of 30. I'm confused...
Haven't used the convertor but it makes sense that if you change interpretation the length of the footage will change.
If you drop a 24FPS comp in a 29 fps comp the length in seconds won't change, but you'll end up with some frame doubling.
The best way to change 24fps footage to 29.97 is to render the footage choosing field render and and some cadence of 3:2 pulldown in the Render Settings. Just make sure that you've got the field order correct for your intended output.
Edit:
Ok, I took a look at the tutorial and the efx preset. I'm not sure I'd ever have a use for it because it's a workflow that I never have used. I'm also not exactly sure what you're trying to accomplish. I can tell, though, by your post, that you're not following the procedure correctly. You've confused the target frame rate and the source frame rate and the interpretation. All the preset is doing is adjusting the speed of your re-interpreted footage so that the time is correct. His expression is sound. If you have your original footage that's 23.976 and you're going to 29.97 then you need to interpret the footage as 29.97, which is going to make it play faster so that it ends sooner. Using the fxx preset you can then speed it up by placing the original frame rate 23.976 in the Actual Source frame rate value, setting the target frame rate of 29.97 in the Target frame rate slider which should give you a 79.98 value in the Frame Rate Warp value (it's pink).
This will slow down the clip so that it takes 30 seconds to playback.
This isn't necessary at all to produce an interlaced output for broadcast from 24P footage. If your footage is actually 24P, then just put it in a 24P comp (23.076) then open up the Render Settings panel and Turn On field rendering and add any of the 3:2 pulldown cadences you want. You're done and it will look exactly like film transferred to tape, and you won't be saddled with the long render times that you'll get using the Timewarp (Renamed FrameRateWarp by Mr Kramer). I'm not sure that you would see any difference in the output. I'd have to run some motion artifact tests to find out.
You could accomplish the same thing by simply dragging the speed slider in TimeWarp to the appropriate value to make your footage the correct length. All the effect preset is doing is making the calculation for you with an expression.
Edit:
One more thing: You mentioned in an earlier reply that some of the interlaced fields were progressive and some were interlaced. That's the correct answer. Your original 24P footage is converted to 2 fields from frame 1, they are identical to so these two fields (or first frame) are progressive, then 2 fields from frame 2 (which are also identical, therefore progressive) then one field from frame 2 and one field frame 3 (which are interlaced because each field is a different moment in time) which gives you your weird interlacing artifacts. That's what film transferred to tape looks like if you step through it one frame (two fields at a time). I never liked the look so back in the day when I shot a lot of TV commercials on 35mm film I ran the camera at 29.97 fps so we didn't have to transfer with 3:2 pulldown. In those days, the late 70's through the mid 90's, most major advertising agencies that I shot for specified that we would run the camera at 29.97 to avoid the 3:2 pulldown motion artifacts. Then for a while, when we first started experimenting with trying to make video look more like film, folks were intentionally adding 3:2 pulldown to their projects. Now that there are true progressive displays and DVD and BluRay players that will actually playback progressive footage, there is little reason to worry about the 3:2 pulldown problem unless you're delivering to someone that only has the capability of broadcasting or playing back 29.97 NTSC footage.
BTW, this problem and all this monkeying around only exists in countries where NTSC was the broadcast standard. No similar problem exists in PAL land.