on the fly frame rate ramping

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androbot2084

Carbonite Member
I have come to the conclusion that what I want is 24p to preserve the film look and to avoid that cheesy 60p soap opera video look. However I have also found that 24p is totally inadequate for fast action. I think that the technology of the Panasonic Varicam that allows variable frame rates is the answer that I am looking for. When the action is slow I can select 24p or even a slower framerate however when the action increases I can ramp up the framerate gradually and accordingly. However I do not want the playback to be either fast or slow motion but the playback should be in real time. I realize that the HVX-200 does not allow on the fly frame rate ramping since recording must be stopped to change the framerate. I believe that carefull selection of on the fly ramping will preserve the film look while allowing increased picture fidelity for fast action.
 
That all depends on how the speed ramping is played back. everyone knows that 24p 30p and 60p footage can be played back without speeding or slowing down the footage. But I would think that it is possible at any frame rate.
 
Now the question is whether or not on the fly speed ramping will preserve the film look? If gradually and carefully done I think it can.
 
the HVX does not do slwo/fast motion on the fly, you have to do it in post. If you want the ability to ramp fast/slowmotion at all times, then shoot at 270p24pN at 60 fps, which will capture 60fps in slowmotion then you can alter the speed accordingly in post
 
Androbot, the Varicam can do what you're looking for as long as you keep the video embedded in a 720/60p stream using frame duplication pulldown.

If you strip out the pulldown it'll become fast/slow motion.
 
If I understand what you're saying, you want variable speed recording AND playback -- you want 24 fps playback for "calmer" scenes, and 60 fps playback for "fast action" scenes, and variations in between, all played back at the frame rate they were shot in.

Though there are cameras which will ramp up and down, obviously, playback is going to be your bigger issue. You can't render a file which will ramp the frame rate up and down; it has to be a constant rate. The best you could do is make a Frankenstein construction in post and render everything to play back at the fastest frame rate -- at 60 fps -- inserting pulldown for the 24p sections and doing some kind of speed ramping in between. Depending on how complex you want to make it, this would be a LOT of work, and even if you get real time motion at both 24 fps and 60 fps (and 30 fps, too), when you ramp between them, you'll be seeing speedups and slowdowns in the footage. You won't get "real-time" smooth motion.

(And no film projector can vary speeds automatically like that.)

But keep in mind, you say you want 24p because you don't want the "soap opera" look of 60 fps. Well, you're still going to get that if you go to 60 fps for your "fast action," and the fast action is going to make that soap opera look even more obvious.
 
Yes of course you will always get slowdowns and speedups of the footage. You get this even with 24p footage with 2:3 pulldown.As far as film projectors are concerned the proposal is to print 48 frames or 60 frames per second and then you can alter the framerate by printing the same frame twice or three times. For conventional releases 24 fps copies can be printed from 48 fps or 60 fps masters. However the real future is digital projection and distribution where the infrastucture for higher framerates and dynamic ramping of framerates already exists.As far as fast action shooting goes most cinematographers simply track the fast moving subject in order to minimize relative movement and achieve good results with 24 fps. But indeed there are a lot of impossible shots such as filming race cars whizzing by in which 24 fps just does not have enough temporal resolution in order to do the job. The ability to shoot and display in higher framerates gives the cinematographer that ace in the hole without destroying the film look because he can always go back to the lower framerate even lower than 24p if desired.So with the technology of the Varicam with its on the fly frame rate ramping capture and display capability I can achieve the perfect film look that does not scream video yet I can get away with all of these impossible shots with faster pans faster zooms without producing unacceptable judder.Of course the alternative is to buy a 120 hertz television which will convert any 24 fps movie to cheesy 48 fps video but my alternative is a lot more finely tuned.
 
Well, that's what I said -- you'd have to render or print to the highest framerate and add a pulldown for the lower frame rates -- a pulldown is adding duplicate frames.

But . . . when you go to 60 fps recording and play it back at 60 fps, you'll be back to the "soap opera" look. If you want to keep it real time, instead of slo-mo, you have to play it back at 60 fps, thus destroying the filmic motion you want from 24 fps.

Unless you're talking about shooting 60 fps and then converting back to 24p -- in which case you'll have all the same motion issues that you'd have if you had shot 24p.
 
If you want to achieve the "filmlook" (in terms of frames/second) you have to shoot for a 24p file. Every cinema projects 24 individual frames per second (sure they often project 48 frames/second these days but you always have to consecutive identical frames). Cinema projector don't speedrampe, they are always 24p. In other words to get the "filmlook" you should shoot for 24p. Yes, fast moving object create a jerky motion but that is part of the filmlook and you can see it all the time in the cinema (try to focus on the background during a fast pan and you will see it). The Varicams ability to speedramp is used for a fluid transition between normal motion to fast or slow motion but the speed the images are projected always remains constant and doesn't change. Changing the speed of the projection always make your footage look less filmlike or let's say look less the way the cinema audience is used too... I hope it makes sense...
 
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For example most people think that Doug Trumble advocated that all movies should be captured and played back at 60 frames per second. Doug Trumble never said that and the truth is that he preffered 24 fps footage over 60 fps footage. What Doug Trumble did when he made his movie Brainstorm starring Natalie Wood was that during the virtual reality scenes of the movie he used 60 fps footage to give the footage a well deserved heightened sense of reality. But the drama portions of the movie he used 24 fps footage in order to preserve the film look. Yet everyone accuses Doug of trying to destroy the film look.

Now if you are making a movie and you want to show people watching television and you zoom in on the television screen will using a higher framerate destroy the entire movie? Or if you make a movie about video games will using a higher framerate just to show the video games wreck the entire movie? And how much of a higher framerate can we use? And what percentage of the footage can be in higher framerates? From my personnel experience I would say that only 2 percent of the footage I have ever shot was in 60p.
 
What do you mean by he used 60 fps footage to give the footage a heightened sense of reality? Shooting 60 fps is just normal slow-motion (2.5 times slower) as you see in almost every movie....
 
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A little knowledge is a dangerous thing. It sounds like you have an understanding of the technology of cameras but less about the human eye. The human eye can see a difference between framerates but can't actually see temporal details faster than about 1/25th of a second (1). Go read the wikipedia entries on frame rate, flicker fusion threshold, and temporal aliasing. Maybe this will put your mind at ease about shooting at 24 or 30 fps.
 
androbot2084 said:
Now if you are making a movie and you want to show people watching television and you zoom in on the television screen will using a higher framerate destroy the entire movie? Or if you make a movie about video games will using a higher framerate just to show the video games wreck the entire movie? And how much of a higher framerate can we use? And what percentage of the footage can be in higher framerates? From my personnel experience I would say that only 2 percent of the footage I have ever shot was in 60p.
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No one said it would ruin the movie; for those limited examples, maybe no one would even notice a frame rate change (but then, maybe they would).

I don't know that it's worth it, though, considering that you'd have to (as I said) render the whole thing out at 60 fps, or project at 60 fps. You give up a lot of the cost- and space-saving benefits of 24 fps.

But, getting away from shooting TV or video game screens, if you use 60 fps for motion which is supposed to be part of the narrative the story -- characters, vehicles, whatever -- then people will notice a difference. In "Brainstorm," if I recall correctly (and it's been many years since I've seen it), there was a narrative reason why the footage would look different. Absent that obvious reason, though, the difference in frame rate will look strange and unnatural, and (again) you're back to the soap opera look.

But hey, do what you want. It's your film. :)
 
what do you mean 24p is not good for fast action? it's been working for years and years and years. try shooting 24p but with a fast shutter speed between 1/250 to 1/1000 if you want things to look dicey but not like cheap video.
 
androbot2084 said:
What Doug Trumble did when he made his movie Brainstorm starring Natalie Wood was that during the virtual reality scenes of the movie he used 60 fps footage to give the footage a well deserved heightened sense of reality. But the drama portions of the movie he used 24 fps footage in order to preserve the film look. Yet everyone accuses Doug of trying to destroy the film look.
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IIRC, Doug Trumbull WANTED to use 60 fps for the special scenes in BRAINSCAN, but that would not have been possible in a normal commercial release. As a compromise, he used a wider aspect ratio for those scenes (and, I believe, 65mm negative--but I may be wrong on that point). It was a big compromise, and did not go very far at all in approximating the kind of effect he was after, because of course 24 fps could not possibly emulate 60 fps...
 
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As an analogy what if we had a choice of only one single speed limit for the entire country such as 25 miles per hour. The proponents of the 25 mile per hour speed limit would say a 25 or a 30 mile per hour speed limit would be the only way to go because we do not want faster speed limits in residential areas or school zones because this would increase traffic fatalities. Yet proponents of faster speed limits such as 60 or 70 miles per hour would say that these higher speed limits would be mandatory if people want to get to work on time. However the proponents of the 25 mile per hour speed limit would say that higher speed limits are nonsense. They would argue that by elinminating stop signs by building expressways complete with tunnels and overpasses traffic will always be moving so who needs higher speed limits higher than 25 mph?

And yet in Hollwood we have imposed a universal 24 frames per second speed limit as a safety measure so in order not to kill the film look. Yet if it is argued that 24 fps cannot keep up with fast action the proponents of 24 fps say nonsense. The use of dollies and steadycams or higher shutter speeds will remove all of the bottlenecks that hinder the capture of fast motion.
 
Nobody's imposed anything as "a safety measure so in order not to kill the film look." That's silly. The speed "limit" is in place because there's a massive wordwide base of hundreds of thousands of 35mm projectors, all of which run at 24 fps.

You're free to shoot your film at any speed you want, most every modern movie camera supports variable frame rates. Editors can usually edit at any speed you want. It's just that if you want to be able to project it on a projector, it had *better* be 24fps or you're hosed.
 
Originally Doug Trumbles Showscan format ignored 24 fps compatibility and shot at 60 fps for the highest picture fidelity and NTSC compatibility. However newer film formats such as Maxivision 48, Super Dimension 70 and IMAX 48 have stressed that content should be filmed at 48 frames per second so that 24 fps versions could be printed that could be playable on any projector. Although these higher frame film formats may never achieve any significant marketshare for theatre projection it is certainly possible to deliver higher frame rates for Blu-Ray disc, HD-DVD, or 4k digital projection.
 
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