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24p for NTSC standard TV broadcasting

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adeeb oberoi24p for NTSC standard TV broadcasting
by on Sep 1, 2009 at 3:23:33 pm

My question is,

Having a 24p (23.976) AE animation that playes in the cinema (digital). Can this play on TV? Or does this again needs to be converted to 29.97?

The TV here converts everything to mpeg.

I have seen some of my 24p spots and they seem to play ok on TV.

Just wanted to get a professional opinion on this,

Thx,

Adeeb Oberoi


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Dave LaRondeRe: 24p for NTSC standard TV broadcasting
by on Sep 1, 2009 at 3:59:33 pm

If you're going to continue working in both 23.976 and 29.97, you would be wise to google the term, "3:2 pulldown". You will find the information very enlightening.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Adolfo RozenfeldRe: 24p for NTSC standard TV broadcasting
by on Sep 1, 2009 at 5:05:12 pm

They will play fine on a LCD/plasma TV, because they are not really NTSC devices. They can bend the rules, sort of speak.
They won't play on an analog TV, and they can't be used as that for broadcast. You would have to add pull-down (as Steve said) for that, so that extra frames are added to make it 29.97 fps.
DVD players can take 24P assets and feed them like that to a (digital) TV. Or they can add pull-down on the fly (it's a bit more complicated, but in practical terms it works like that), if you set them for an analog NTSC TV.

Adolfo Rozenfeld ยท Adobe


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Kevin CampRe: 24p for NTSC standard TV broadcasting
by on Sep 2, 2009 at 3:10:02 pm

hi adeeb,

adolfo touches on this, but in sd ntsc broadcast and any sd broadcast device, like video tape (any type: beta, dvcpro, d-5...) all footage will be 29.97. so the spots you created in 24p have had a pulldown added at some point.

if you had laid the to tape, then you actually added the pulldown with out knowing it, because tape will only record at 29.97. if you provided a file, then a pulldown was added at some point prior to air, quite possibly when they put it to tape, or at ingest into their system.

hd is a bit different, 1080 will get a typical pulldown cadence added, since it needs to be 29.97, but 720 is 59.94fps so it will be adding more frames to compensate for the frame rate discrepancy.

also, if you needed/wanted to add a pulldown to your rendered file, you can set that in the render settings (as i mentioned in your other post). you'd set the render fields option (pick the order, lower for most for sd, upper for 1080), then pick a pulldown cadence (like swwws). you should notice that the frames rate will then change from 23.976 to 29.97.

720 would get trickier. since it is progressive, you can't use the field render option and pick a pulldown. you'll need to go into the comp settings, click the advance tab and set the option to 'preserve comp's frame rate when nested'. then drop that comp into a 720/59.94 comp and render that.

remember, this is only for broadcast... if your footage is for dvd/blue ray, film output or computer/web, broadcast frame rates won't be necessary.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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adeeb oberoiRe: 24p for NTSC standard TV broadcasting
by on Sep 2, 2009 at 5:36:21 pm

Whow thnx every one, sounds complicated though.

I acctually dont record to tape, do most animations diggitally then deliver a quicktime to the TV station.

Even 1080 and 720 I do rendr progresive (never added a pulldown yet, if in 29.97 needs to go to The movies I make it 23.976 with the method Kevin explained (gets a bit longer though so I rest some stuff).

The Tv station just convertes to MPG, no tape... I guess in that conversion they make it 29.97 again....they broadcast on mpeg.

Question:

1. Is the way I work ok?
2. How do you convert back from 23.976 to 29.97 NTSC (with puldown) and will there be anny loss in quality?
3. can the animation sty 23.97 amd ad a pulldown and still be able to broadcast?

Thsnks so much, I feel I need to know this stuff or at least the basics. My clients pay so I want to make sure all goes well with theire product.



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Kevin CampRe: 24p for NTSC standard TV broadcasting
by on Sep 2, 2009 at 6:02:52 pm

it's fine to work in 23.976.

personally, if i know my piece is only going to broadcast (and since i work at a tv station almost all of it is) then i would choose to work in 29.97 (or 59.94 for 720). 29.97 will have smoother motion, but so many tv shows and ads are shot in 24p now that it has become quite common to work that way.

if you work in 23.976, there will be no loss of data adding a pulldown to get to 29.97. nor will there be any loss going back to 23.976. to take 24p footage/render that has a pulldown added (to make it 29.97) back to 23.976, you'd use the interpret footage settings to remove the pulldown (select file in project window and choose file>interpret footage>main, select separate fields pick the order and then choose remove pulldown and pick the cadence). once that is done, ae will see the footage as 23.976 progressive.

i'm unclear on what you last question was.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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adeeb oberoiRe: 24p for NTSC standard TV broadcasting
by on Sep 2, 2009 at 6:23:58 pm

Sory, the question was.

Can a puldown be added to 23.976 without converting it to 29.97 and still be delivered to TV?

Thanks for the help.

Adeeb


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Dave LaRondeRe: 24p for NTSC standard TV broadcasting
by on Sep 2, 2009 at 6:44:10 pm

[adeeb oberoi] "Can a puldown be added to 23.976 without converting it to 29.97 and still be delivered to TV? "

No. The only reason you would add pulldown to a 23.976 comp's Render Settings in the Render Queue is to convert it into a completed 29.97 file. The process of 3:2 Pulldown only exists to smoothly spread a film frame rate across an NTSC frame rate.

As Kevin wrote, adding pulldown doesn't affect the quality of the render. It's just a time-tested way to get a film frame to play properly on TV.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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