24f(p) or 60i for Documentary?

[Steve Lewis]

Hey guys,
I am going to start shooting a doc on tuesday and I am not sure which frame rate to shoot in. What are your suggestions for a video will be about a marathon ocean swim in the Santa Barbara Channel? There won't be too much motion, aside from the handheld footage I shoot on a boat. Do you know if i can mix 24p footage with 60i material in an NLE like Final Cut Pro? Any help would be great, thanks!
-Steve

[Jack Zhang]

Best to shoot in 60i since a 24p clip in a 60i timeline will have mis-matching frame rates for fades and motion animations.

[Steve Lewis]

What about dropping a 60i file into a 24p timeline?

[Ron Evans]

Unless you are going to film why do you want 24p? 24P has so many ways of making video look really bad on progressive displays that I really wonder why anyone would want to use it at all. The juddery video is getting more prevalent on cable that a lot of shows to me are becoming unwatchable. We will start to see more 120hz LCD on the market designed to take out the juddery motion and interpolating the extra frames that the camera didn't take so that the camera person could say they shot 24p!!!! A case of the consumer wanting smooth motion satisfied by the manufacture providing technology to cover for the shooting technology of producer of the program!!!!

Ron Evans

[Steve Lewis]

Originally Posted by Ron Evans

Unless you are going to film why do you want 24p? 24P has so many ways of making video look really bad on progressive displays that I really wonder why anyone would want to use it at all.

Shouldn't a progressive movie looks just fine on a progressive display? Anyways, I wanted to shoot in 24f (canon's version of 24p) for the filmic look that everyone seems to be after these days. Also, I plan on submitting it to a film festival and they suggest shooting in 24 fps. Also, sites that offer HD video sharing, like Vimeo play 24p files much smoother than 60i. Another question however: is 24p okay for distribution on DVD?

[Ron Evans]

Progressive displays in North America refresh at 60hz. It isn't possible to divide 60 by 24 and get an even number. So to display 24p the display has to do something to the input to make it work. Normally repeating frames( 3,2 pulldown), but not every frame so that the motion is not uniform. The displays that are 120HZ are able to display( 120/24 = 5) however most of these displays also interpolate the extra frames,that weren't there, to get 120 frames a second. So the motion you were after with 24p is poorly presented on most TVs, either introducing judder or interpolated to a smooth 120 fps. IF you are going to film that is very different. Film gets projected at 24fps with normally a 3 blade shutter giving 72 flashes a second. No adulteration of the frame rate just raising the flicker rate to make it appear like moving images to a human being ( a fly would still see it as a series of stills). There is a lot more to the film look than 24 p. Camera motion is critical( as little as possible), shallow depth of field ( because the backround will stutter and it's best made out of focus) avoid motion across the scene ( it will enhance the stutter problem) etc etc.
If you are going to shoot for video shoot 60i. If you want to make a film but shooting video as the source is cheaper shoot 24p, but don't shoot as if it was video, shoot as if you are using a film camera.
As you can tell I am not a fan of 24p. To me its a bit like buying a modern car and insisting it ride like a Model T Ford!!!! 24fps for film was a limitation of technology and investment of the last century. A combination of how slow a film could be run and still have a reasonable sound track and still not break the bank in terms of film distribution costs to all the movie houses. None of the limitations exist today so I see little reason to continue to follow a path set by movie house investment of the last century. For me the answer is high frame rate high definition 60p, it can be displayed by all the current progressive displays at least at 720p and conversion to 30p for the WEB is also easier and will have none of the stuttering issues of 24p.

Ron Evans

[Peter Moretti]

Originally Posted by Jack Zhang

Best to shoot in 60i since a 24p clip in a 60i timeline will have mis-matching frame rates for fades and motion animations.

Jack, You are supposed to remove the 3:2 pulldown before editiing. If you do this, what your are saying won't happen.

[Peter Moretti]

Steve,

IMHO, if your subject is fast moving or the camera will be doing quick pans, then consider 60i. Otherwise, I'd go with 24p.

In an effort to look "filmic," a lot of documentaries are shot in 24p. So 24p may be something festivals and distributors see as a plus. I just watched four documentaries this past week and got to ask the filmmakers questions. I stopped asking the 60i/24p question, b/c it became pretty obvious 24p would be the answer. And these films ran the gamut from 16 mins arthouse picture to Academy Award nomiated feature. Surprisingly, two them had quite a bit of movement.

One real adavantage of 24p that often fails to get mentioned in these types of discussions is that it requires less light than 60i. And in adequate light, it allows you to open the lens wider to create shallower DoF.

HTH.

[Tom Roper]

24p has the advantage it can be ported to pal, with 4% speed change.

But why not shoot both? It's going to be broadcast at 60i anyway. Just add 3:2 pulldown flags to the 24p and put it inside a 60i stream along with native 60i. The TV set will remove the pulldown and play it back as 24 fps progressive or at 72 hz, 120 hz etc. It's going to look the same. A good display will play it back without artifacts, and you aren't in control of the viewer's display type anyway. And if you were to insist on 24p progressive encoding without pulldown flags, the broadcaster is going to add them for you, unless you are distributing the collaboration on Blu-ray or DVD.

I don't see any reason for not shooting in the format you like, even mixing them inside the same program.

[Evan Donn]

Originally Posted by Ron Evans

The displays that are 120HZ are able to display( 120/24 = 5) however most of these displays also interpolate the extra frames,that weren't there, to get 120 frames a second. So the motion you were after with 24p is poorly presented on most TVs, either introducing judder or interpolated to a smooth 120 fps.

I was wondering about the interpolation issue - I wasn't aware that any 120hz displays were actually interpolating additional frames. However I was in best buy recently and they were running a blu-ray demo on a 120hz tv with clips from a bunch of major feature films - it was one of the most shockingly bad things I've ever seen. 'Gone in 60 Seconds' (the nic cage version) is hardly a cinematic masterpiece, but it's amazing how much worse it looks shot on home video - which is exactly how it looked as what I can only assume is interpolated 120fps video. Add to that the occasional odd artifact on the edges of occluded objects during camera moves and it was truly bad. I was hoping it wasn't a function of the display and just an overzealous editor who ran everything through twixtor or something.

I'd recommend going with 24p - I've yet to see a situation where it produced worse images, pulldown or not, on a progressive display compared to interlace. It compresses significantly better for online delivery than 60i or even 30p - and the reality is anything you produce now should have online delivery as a big consideration. It's much better to work with in post if you're planning to do any kind of significant work in AE, etc. Shooting at 1/48th you also get more light... as others have noted though you need to be more careful about shooting it. Handheld is going to require some sort of stabilization/brace with small cameras and you need to keep pan/tilt speeds down unless you're following a moving subject.

[Jim Andrada]

I think Steve said he would be shooting from a boat. I would think the boat motion as well as wave motion might make 24P a less than ideal choice. Even if the distant waves were out of focus there would be lots of wave motion near the swimmers which should be in sharp focus.

Maybe it depends on the size of the boat - the QM 2 would probably be a pretty smooth platform but a smallish boat in any kind of choppy conditions would be bouncing around a fair bit.

Am I missing something? Comments?

[Ron Evans]

Originally Posted by Evan Donn

I was wondering about the interpolation issue - I wasn't aware that any 120hz displays were actually interpolating additional frames.

To my knowledge all the 120HZ displays interpolate the extra frames. Certainly that is the marketing pitch from Samsung, Sony and LG. IT is an attempt at smoothing out the natural judder of an LCD display whether it is showing 24p or not. For 24p, I think it is called cinema mode or something the displays should sense the 24p input and repeat frames rather than interpolate to emulate a film projector. Not sure how good they are that either!!!. To me the smoothest images at the moment are from 720P60. They don't mess with the display cadence and have good motion without judder of 24p. Most computer LCD displays also refresh at 60HZ so 30P would be a better choice for internet distribution sometimes 15fps so neither of these matches 24p very well either. 24fps is a film legacy unless one wants to make a film master I see little point in shooting 24p. If you must shoot progressive shoot 30p or 60p they will give better motion and save the poor viewer from a juddering mess when shown on a video display.

Ron Evans

[Evan Donn]

Originally Posted by Ron Evans

24fps is a film legacy unless one wants to make a film master I see little point in shooting 24p. If you must shoot progressive shoot 30p or 60p they will give better motion and save the poor viewer from a juddering mess when shown on a video display.

I've watched many, many hours of 24 frame originated material (films, television shows, my own & other's 24p videos) on a wide range of video displays, from CRT to LCD, Plasma and LCD & DLP projection and I have yet to see anything I'd call a 'juddering mess' short of the occasional hand-held home video - certainly nothing that was shot professionally. When you watch tv or a feature film on an LCD or plasma (not a new 120hz model) do you see a 'juddering mess'?

[Robert Morane]

No Reservations with Bourdain is shot in HDV 24P; look good to my eyes on TV as on my MBpro when downloadded from Itunes.

[Ron Evans]

Originally Posted by Evan Donn

When you watch tv or a feature film on an LCD or plasma (not a new 120hz model) do you see a 'juddering mess'?

Unfortunately I feel a lot of what I see on my Panasonic 1080p Plasma over cable is a mess. Normal HD TV which is 1080i or 720p is smooth some programs have considerable judder including most films. Compared to my own HDV or AVCHD played back on the same plasma a lot of cable has a considerable amount of judder. I find my PS3 upconvert to 1080p30 is also unacceptable. I find it better to use my old Sony DVD player and let the Panasonic convert to progressive at the display. I may be very sensitive to judder but thats the way it is. I have a few Bluray discs and find them to have considerable backround judder too. They are concert discs likely shot in 30p. I have yet to see them from another player. The PS3 will play back 1080i AVCHD just fine but seems to insist on converting others to 30p. I guess it is just my old eyes but I dislike the judder in film I took in the early 60's and have tried to remove this defect ( in my eyes) ever since. For me its 60i or 60p or faster. My eyes don't work at 24p they require refresh rates in access of 50hz to give smooth motion, 60hz is better. Repeating the same frame doesn't remove the judder just exceeds the flicker rate for ones eyes. Shooting video at less than this rate means there are missing frames of information. One can just ignore them and judder from one frame to the next, one can shoot at the higher frame rate of the display or can use technology to fill in the missing pieces( attempted by the 120hz displays) . My preference would be to match the frame rate of the display refreshing at 60hz or greater.
Shooting at 24p doesn't match any video display. It is a valid approach to get to film. If you shoot purely for video then today the best is 60i( or 50i in PAL). To get better progressive motion shoot HD 720p60.

Ron Evans