pulldown confusion

[First Last]

How’d you capture the footage?

Go fly fishing.

[Matt Campbell]

I didn’t. This was a 23.976p project I got from our post house. I’m simply doing the :5 tag for the :25-5 commercial. They’ve already added the pulldown into the 24p file giving me a 29.97 1080i ProRes file. They’ve told me its 3:2 pulldown and in QT it steps through that way, but I just don’t understand why stepping through in FCP, its 1, 2, 3, 4 and a duplicate frame (4:2).

OS 10.6.3, Mac Pro 2 x 2.66 ghz quad-core intel xenon, 16 gb ram, with BM Intensity Pro card

[Scott Sheriff]

Matt
“They’ve already added the pulldown into the 24p file giving me a 29.97 1080i ProRes file. ”

Well, how can you do 2:3 in progressive?

From wikipedia on 2:3 pulldown:
The term “pulldown” comes from the mechanical process of “pulling” the film down to advance it from one frame to the next at a repetitive rate (nominally 24 frames/s). This is accomplished in two steps. The first step is to slow down the film motion by 1/1000. This speed change is unnoticeable to the viewer, and makes the film travel at 23.976 frames/s (or 7.2 seconds longer in a 2-hour movie).

The second step of the 2:3 pulldown is distributing cinema frames into video fields. At 23.976 frame/s, there are four frames of film for every five frames of 60 Hz video:

23.976/29.97 = 4/5

These four frames are “stretched” into five by exploiting the interlaced nature of 60 Hz video. For every frame, there are actually two incomplete images or fields, one for the odd-numbered lines of the image, and one for the even-numbered lines. There are, therefore, eight fields for every four film frames, which are called A, B, C, and D. The telecine alternately places A frame across two fields, B frame across three fields, C frame across two fields and D frame across three fields. This can be written as A-A-B-B-B-C-C-D-D-D or 2-3-2-3 or simply 2-3. The cycle repeats itself completely after four film frames have been exposed:

And I’m guessing the pulldown was actually done at the camera. Why do people insist on shooting 24p if they know they are going to use this material in a 29.97 world?

Scott Sheriff
Director
SST Digital Media
https://www.sstdigitalmedia.com

[Matt Campbell]

Long story, but the spot was shot on film. Pulldown was not done on camera. 1st spot was edited at 23.98, master created to broadcast spec at 29.97, went out and aired from post house A. many months later the spot needed 1 revision. Original post facility A was not available, so it went to facility B. They have since been working with the 29.97 material. It would cost time and money to go back to the 24p (23.976) material. I’m simply creating and adding a :5 tag to the 29.97 material.

So after reading that, I’m assuming what I have is correct? And the 29.97 material has had the proper pulldown added.

OS 10.6.3, Mac Pro 2 x 2.66 ghz quad-core intel xenon, 16 gb ram, with BM Intensity Pro card

[John Heagy]

Set your viewer, source or canvas, to 100% and all will be revealed.

[Mike Krause]

Don’t forget, on the Blackmagic cards (at least the Decklinks) you need to un-check the box in the settings that says “Remove field jitter when video is paused. Pulldown should then show correctly on your program monitor.

[Matt Campbell]

John, thank you. I always forget to check the little things. Setting canvas to 100%, duh, you can now clearly see the 3:2 pulldown. At 48% size it looked like 4:2. solved.

Mike, thank you as well. Unchecking that box for my Intensity Pro card then reveals the pulldown on my TV when playback is paused. So now the Canvas and external TV show the same thing.

DUH. thanks again guys. i’ve got to right this down or something.

OS 10.6.3, Mac Pro 2 x 2.66 ghz quad-core intel xenon, 16 gb ram, with BM Intensity Pro card