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Frame rates

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Jeff Carbonneau
Frame rates
on Jan 5, 2016 at 11:58:29 pm

So I've been shooting commercials and corporate video for quite a while since 2000. I've always gone back and forth between the 23.98 vs 29.97 argument. With a majority of shooting 23.98 because I like the look. I've perfected my camera moves to avoid too much judder when shooting 23.98. So I've noticed national spots (like dunkin donuts) like there shot on film and what appears to be 23.98 I guess. I shoot on the ursa with a lighting crew, dolly, etc. my question is are national spots shot in 30p because they look so smooth with no strobe. Also, when a film is shown on tv is 3:2 applied because I don't notice it if it is? always been curious because when I shoot in 30 it always looks so "Video-ish". 23.98 looks more expensive to my clients, but I want it smoother when pull down is applied. Any insight would be extremely helpful. Thanks


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Todd Terry
Re: Frame rates
on Jan 6, 2016 at 1:10:39 am

National spots (well, at least one with a cinematic look rather than a video look), are almost invariably shot at 23.976p. Even 35mm real film commercial shoots (those that still exist) at shot at 23.976fps rather than true 24fps. Although it does happen, you won't find too many commercials shot at 30p. 24p is by far the norm.

Of the two ways this is usually done, one is to shoot at 24p, convert the footage to 60i (or just edit the 24p footage on a 60i timeline), and output the final broadcast master at 60i.

The other way is the way we do it.... we shoot at 24p, and then we also edit at 24p, and create a 24p master. Then for broadcast we will output a 60i version (upper field first) for television stations. That creates the perfect 3:2 pulldown that looks right. That also allows us to retain the final project with a 24p master which is both what we really want it to look like, plus is much better for non-interlaced usages (such as when clients also want a version to put on their websites or YouTube, etc.).

If your footage looks too juddery, a couple of things might be happening... firstly your camera moves might be too fast. They need to be no faster than if you were shooting real film, not the speeds you might be used to with a video camera at 60i. The ASC manual I think even has a table in it that will tell you maximum pan and tilt speeds for various focal lengths... but just your eyeball should tell you (I've never used the tables). The other thing that could be happening is that you might be shooting with too high a shutter speed. A "normal" shutter speed is "one over twice the frame rate." So, if you are shooting 24fps, the optimal frame rate would be 1/48th. That rate will give you the amount of motion blur you need for your brain to interpret the footage as smooth. If you purposely jack up the frame rate (or accidently do so), the higher it goes the more strobby the footage will look (the "narrow shutter" look that you'll see used to make action movies look more "actiony").

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Jeff Carbonneau
Re: Frame rates
on Jan 6, 2016 at 3:10:56 am

Thanks for the insight Todd. thats exactly the method I do with one exeception. I make my 24p master, bring a self contained movie into compressor or ame and do a 1080 mpeg 2 around 40mbps. so I'm in the process of switching from compressor to ame for my compressing duties as my tests yield faster better results. When I had my mpeg2 setting in compressor I could've sworn it was set to progressive on the 3:2 pull down 24 to 30. When did my test today in ame progressive looked much better the interlaced upper. I did 2 tests one with progressive and one with interlaced upper. Progressive didn't have the weird frame blending that the interlaced version had. Is it possible that the stations have been receiving progessive and converting it? Maybe the compressor version was interlaced I'll have to check. Anyways, I do have to say any sort of frame blending looks too blurry and takes sharpness from any moving images. Quick thoughts on that and thanks again.


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Todd Terry
Re: Frame rates
on Jan 6, 2016 at 4:27:23 pm

Hi Jeff...

I might not be tons of help on your exact methods or settings... we don't use Compressor (or any Apple products at all actually, except I think there's one ancient Mac upstairs in Graphics that is a paperweight).

It's easy to check to see if your 3:2 pulldown is working correct, though. Take one of your finished output 60i files (preferably a second or so that has some action or movement), and click through it frame by frame, while watching it on an interlaced CRT monitor (or even your tube television from 2003). You'll readily be able to see the 3-and-2 pattern. You should see three frames in a row that look progressive... totally stock-still frozen. These will be followed by the next two frames that are obviously interlaced... on a CRT you'll see the image vibrating between the two sets of fields when you park on that frame. Those will then be followed by three more progressive and two more interlaced, and the sequence repeats until the end.

Maybe someone else in here can help you with the Compressor issues... but you did mention "frame blending." Usually something that says "frame blending" is an option that you would never want to turn on, unless you are using footage at something other than its native frame rate... for example, if you want to take 24fps footage and use it at 16fps for a slight slow-mo look... that's where frame blending can help. But for something like converting 24p to 60i.... no, never.

Sorry I can't be of more help....

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Jeff Carbonneau
Re: Frame rates
on Jan 6, 2016 at 4:54:07 pm

Thanks Todd! I don't have a CRT. Just LED. Also, just to clarify, this might be an intentional mistake on my part but I do in fact upload MPEG2 progressive to the stations and they've been accepting it for years now. My steps are the following.... shoot 23.98 Prores HQ, edit 23.98 Prores HQ, render out self-contained movie, bring it into compressor, choose mpeg2, 1920x1080, 35mbps, 29.97, when I jog the render through frame by frame the pattern is that is duplicates every fourth frame on the fifth and so one... This looks the best to me and I've never had a station question it. I just did do the interlace test and saw the pattern even on the LED. I see what you're talking about. Embarassed to say I should've seen this years ago. To the eye the progressive render always looked better so I always sent that. It's weird that I've never been called on it. Anyways, thanks for your help Todd.


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Todd Terry
Re: Frame rates
on Jan 6, 2016 at 5:57:06 pm

For television broadcast, for 1080 files you should always deliver your Mpeg2 files as interlaced... never as progressive.

It has probably been looking "right" to you because you've likely been looking at it only on a progressive computer monitor, probably. If you could see it on an interlaced CRT monitor or on a LCD/LED/OLED/Plasma monitor that is a real TV monitor (even though progressive) you'd probably notice the difference.

Progressive files look great on a computer monitor, and 24p progressive files look great on a TV monitor (especially a monitor that can display true 24p). But while 29.97 interlaced files look great (and correct) on a TV monitor, they do indeed look terrible on a computer monitor.

This is a battle that we all fight all the time, and you have to be a little watchful of it. At my place we have monitors of several flavors... in two suites the computer monitors are LCDs but the editor's main production monitor is LED, and there is also a plasma monitors for clients, and a standard-def CRT monitor in both. It's kind of amazing that something that can be perfect on one monitor will look terrible on one of the others, so we keep watch to make sure it always looks right no matter what flavor of screen a home viewer will be using. The CRTs are the ones, even in standard def, that will most readily show a flaw or interlacing error. If it looks great/right on the CRT, nine times out of 10 it will look great on all the others, too.

I had a minute to kill so I snapped a pic to show you the setup that I usually look at in my suite...



I'm kinda surprised that no television station has rejected a progressive file... at least for 1080. 1080 can obviously be 1080i or 1080p, but broadcasters use 1080i, upper field first. Obviously all 720p files are progressive by definition (no such thing as 720i), so if you ever are called on to deliver a 720p file that will be a progressive file, but the higher frame rate makes them act/appear/function as interlaced when they are actually broadcast.

Those stations are probably actually converting your file to interlaced, or they are simply playing them as-is and since they are transmitting an interlaced signal in the end you are getting the same result... which is the bad 4:1 progression (with the incorrect duplicated frame) rather than the correct 3:2 frames/fields. That duplicated frame can definitely add to the "judder" look, quite a bit actually.

Let us know if it works better for you in the future.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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