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Topic: TV - 24fps or 30 fps?

Mathias Andersson
Film Handler

Posts: 26
From: Sweden
Registered: Oct 1999

posted 08-06-2001 05:38 AM

Somewhat off topic depending on the answer...
TV-series such Star Trek Voyager and The X-Files, are they shot in 24 fps and then a 3:2 pulldown is applied or are they shot directly in 30 fps? Also, do they use 35 mm film?

// Mathias

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Tao Yue
Expert Film Handler

Posts: 209
From: Princeton, NJ
Registered: Apr 2001

posted 08-06-2001 07:37 AM

I can't be certain about the two shows you mentioned. However, it is my general impression that shows shot on 35mm are filmed at 24 fps. The original Star Trek and Star Trek: The Next Generation, for example, both exhibit 3:2 pulldown artifacts.

The simplest way to tell is to tape an episode of the shows and run through it as slow or frame advance. Because VCR frame advance usually treats the video data as frame rather than fields, you'll see every fourth frame repeat in a 3:2 pulldown.

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Tao Yue
MIT '04: Course VI-2, Electrical Engineering and Computer Science
Projectionist, MIT Lecture Series Committee

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Michael Brown
Phenomenal Film Handler

Posts: 1522
From: Bradford, England
Registered: May 2001

posted 08-06-2001 07:51 AM

If the shows are shot at 24fps on 35mm are they simply shown speeded up on uk 25fps tv or will the british versions be converted from the ntsc versions.

(p.s shouldn't this be in yack)

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Mathias Andersson
Film Handler

Posts: 26
From: Sweden
Registered: Oct 1999

posted 08-06-2001 08:05 AM

To speed up a 24fps film to 25fps is the best soultion I think. But how does the process work for converting 30fps to 25fps? If the show is shot in 30fps they can't use IVTC and then speed it up to 25fps.

// Mathias A

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 08-06-2001 08:17 AM

From the books I have on film technology, I have read that in the UK, they do just speed the film up to 25 FPS. But then, again, the book I refer to dates back to the '70s.

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John Anastasio
Master Film Handler

Posts: 325
From: Trenton, NJ, USA
Registered: Sep 2000

posted 08-06-2001 08:33 AM

The upconversion of 24fps to PAL is such a complicated mess (more so than a 3:2 pulldown, since the phase alternates in PAL) that every country I'm aware of in Europe simply scans the film at 25fps. When the whole world goes digital, it won't make a bit of difference.

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Michael Brown
Phenomenal Film Handler

Posts: 1522
From: Bradford, England
Registered: May 2001

posted 08-06-2001 08:43 AM

for movies in the uk the 24fps film is simply sped up to 25fps for tv and video.

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Greg Mueller
Phenomenal Film Handler

Posts: 1687
From: Port Gamble, WA
Registered: Jun 99

posted 08-06-2001 08:59 AM

The original Trek series was shot in 35, as I've seen prints of the episodes

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Greg Mueller
Amateur Astronomer, Machinist, Filmnut
http://www.muellersatomics.com/

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Evans A Criswell
Phenomenal Film Handler

Posts: 1579
From: Huntsville, AL, USA
Registered: Mar 2000

posted 08-06-2001 09:23 AM

Something I've always wondered about:

When a show originates in an area where 50MHz PAL is used, and the shows are converted to 60MHz NTSC, how exactly is that conversion performed, since the number of scan lines are different and the frame rate is different? Any way of doing it that I can think of would create some undesirable artifacts in the picture due to beat patterns going from 625 to 525 scan lines.

Shows such as Monty Python's Flying Circus, Mr. Bean, Absolutely Fabulous, and the Young Ones don't seem to be degraded in any such manner when I watch them. Were they shot on film so that they could be converted from film to NTSC, or were some of the shows videotaped originally in PAL?

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Evans A Criswell
Huntsville-Decatur Movie Theatre Information Site

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Mathias Andersson
Film Handler

Posts: 26
From: Sweden
Registered: Oct 1999

posted 08-06-2001 11:48 AM

Evans, I've also wondered about that. I think there must be some equivalent formula such as 3:2 pulldown that applies to the PAL --> NTSC conversion.

// Mathias

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 08-06-2001 12:07 PM

Here are several links:
http://www.cybercollege.com/tvp009.htm
http://www.playbackmag.com/articles/magazine/19981005/23352.html
http://www.screeneditors.com/news/14a3.htm
http://www.broadcastpapers.com/editing/single01.htm

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

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Phil Connolly
Film Handler

Posts: 80
From: Derby, England
Registered: May 2000

posted 08-06-2001 01:08 PM

Normally when you convert 24fps film to 25fps Pal you also have to run the audio through a pitch shifter (down 4%) to stop it getting too shrill.

NTSC: converted to PAL can look nasty, with very jerky pans. It looks very similar to 60i NTSC - printed to 24fps film eg Blair witch.

I think most big US shows are shot at 24fps because there are no skipped frames and its cheaper to shoot at 24fps than 30fps.

If you rent the PAL version of 'Oklahoma' you get the Cinemascope(24fps) version not the TODD-AO(30fps).

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Jeff Stricker
Master Film Handler

Posts: 481
From: Calumet, Mi USA
Registered: Nov 1999

posted 08-06-2001 02:50 PM

I believe all US film origination destined for TV is 24 FPS.

The US TV frame rate is 30 frames/sec. The US system uses interlace scanning such that each frame consists of two fields: the first field of a frame having the even numbered lines and the second field the odd numbered lines. This two fields-per-frame system really improves flicker. Information to syncronize the TV receiver's scanning to the scanning at the station is contained in the blanking interval on the top and side of the picture. You can view the syncronizing pulses (and other stuff sent during the blanking period) by turning the brightness up and tweeking the vertical and horizontal controls.

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Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 08-06-2001 05:35 PM

Star Trek: The Next Generation did something absolutely horrible. While the real life people were shot at 24fps, the special effects were rendered at 60 fields per second, making them look horribly out of place. I don't think Voyager was guilty of this and I've never watched Deep Space Nine. I think ST:TNG was a little too goody two shoes for me.

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Bruce McGee
Phenomenal Film Handler

Posts: 1776
From: Asheville, NC USA... Nowhere in Particular.
Registered: Aug 1999

posted 08-06-2001 06:38 PM

I used to have a roommate that watched Voyager, and DS-9 EVERY night. I enjoyed Voyager, but hated DS-9 because it is so S-L-O-W.

I've got several 35 prints of TV shows, and they are filmed at 24 fps.

I've got a RCA TP-66 telecine projector out in the garage/future theatre that I use for copying 16 stuff to video. Too bad I cant copy silent stuff at 18 fps or so... I love a flicker-free image with a home camera! On it, the film runs at 24 fps, but the combination of this and the 5-bladed shutter makes it run at 30 image interruptions per second. Fine for NTSC

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