Frame rates: Would you like half as much twice as often?

In an extensive interview at Variety, James Cameron has a lot to say about 3D production, but he also mentions the paper tiger that is 4K resolution for movies:

4K is a concept born in fear. When the studios were looking at converting to digital cinemas, they were afraid of change, and searched for reasons not to do it. One reason they hit upon was that if people were buying HD monitors for the home, with 1080×1920 resolution, and that was virtually the same as the 2K standard being proposed, then why would people go to the cinema?

He suggests that instead of having 4K (a 4096×3112 frame) 24 times a second, it’s better to go for 2K (2048×1536) 48 times a second. This would reduce the motion artifacts seen at 24 fps. ‘Motion artifacts’ most often happen when the camera pans too quickly – a juddering effect when 24 frames every second isn’t enough to show all the detail we would normally see if we turned our heads at the same rate.

[For those of you who are used to 2K being 1920×1080 and 4K being 4096×2160, I’m referring to the resolution of the full 35mm frame, which is cropped down for different aspect ratios when projected. Wikipedia has more on this.]

Artifacts also occur when objects such as cartwheels and hubcaps have detail that rotates at a rate that is close to 24 frames a second – as a picture is taken every 24th of a second and the pattern looks very similar avery 24th of a second, it looks as if the pattern hasn’t moved far and that the wheel is moving very slowly even though the cart or car is moving quickly.

If regular patterns are close the frame rate, you get strobing. The upper wheel is moving three times slower than the lower wheel.

The spokes in the lower wheel are moving so fast that they rotate almost as far the distance between two spokes, which makes it seem as if the spokes are moving backwards. You can see from the broken spoke that the wheel is still moving forwards.

Juddering pans and strobing wheels still occur at 4K. 4K gives us a more accurate representation of these effects. 2K twice as often will reduce these effects a great deal.2K at 48fps is better than 4K at 24fps. Temporal resolution is more important than visual resolution. This is why interlacing has survived into the digital era – those who want to show sport insisted in rates of 50 or 60 frames per second for their broadcasts. Due to bandwidth limitations, the would rather have half the vertical resolution (1920 by 540) twice as often.

Another advantage is the data rate for storing and communicating the footage would be less: 24 times 4096×3112 is 306 million pixels per second whereas 48 times 2048×1536 is 151 million pixels per second.

Cinema owners may have to let go of beating in-home systems using visual technology, they’ll have to concentrate on the architectural and social elements of a big night out at the movies.

If 2K at 48fps is adopted the post process will need to produce content that can be generated at both frame rates. 24fps has been a standard for so long that it will take years for projectors around the world to be replaced with digital projectors. As it costs $1,500 to produce a film print at 24fps, the sum will almost double for 48fps. With reel breaks happening twice as often, film projection at 48 fps isn’t worth the benefits of providing extra temporal resolution.

This isn’t that much of a big deal for editors. If we treat the extra frames per second in the same way we (used to) deal with interlaced footage, there shouldn’t be too much of a problem. Timecode can stay the same. We’ll stick to making edits only on 24ths of a second. If a 48fps movie is being mastered, it’ll get a bonus frame at the end of each shot. We’ll probably edit away at 24fps for now. Once the edits have been agreed on, we’ll be able to watch at 48fps to see if any moments added at the end of a shot are undesirable. We can then move the edit back a 24th of a second if need be.

It won’t take too much effort for Avid, Apple and Sony to add features to enable 24/48 fps workflows in their software. The sooner they do, the better the fidelity of the movies we make.

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21 comments
  1. Acmade said:

    Yes but 24 fps is beautiful. It’s reminiscent of the flicker of the campfire and part of the appeal of movies. It puts our brains in a dreamlike state and opens us to the suggestions of the filmmaker. Film at 48 fps may be “better” in a technical sense, but to my mind it is lacking in poetry. If a higher framerate is so desirable, why are video people so quick to sacrifice it in favour of a “film look”?

  2. Mat said:

    I agree with Acmade, we’ve got some sort of cultural connection with 24fps, and I don’t believe we’ll move away from it. I think modern home TVs run at 120Hz to take advantage of 24fps Bluray; mimicking the film look as much as possible. So even if films were to be shot at 48fps (and maybe action films will be), Bluray would have a firmware update to play back at 48fps, and TVs would gain the ability to run at 96Hz.

  3. Alex said:

    Tim Sassoon says:

    And the frame-rate issue. I personally think it’s a reality vs. memory/dream
    state issue that is contextually important but that no categorical decisions
    can be made about. Generally, things we want to see as real, like sports and
    news, play better at higher frame rates, to be more transparent. Fiction and
    fantasy usually plays better at lower, less realistic frame rates, and it’s
    sometimes disturbing to mix the two. Looking at older 16mm news footage can be a
    bit unsettling nowadays.

    This is from a mailing list discussion at http://www.cinematography.net

  4. Della St said:

    At some point, fairly soon in the grand scheme of things, frame rate and resolution will ultimately be an artists choice. It won’t be a question of whether or not someone can project it. They will all be interchangeable, and left to the artists to decide how they want to shoot it – and the projectionist will adjust accordingly. Let’s face it, had our forefathers in cinema been given the tools we have to achieve the best picture quality (frame rate and resolution) they surely would have chosen it over what they had. The “standard” of 24fps is only standard because for so long it was all that was available. I do enjoy the look of films (digital or otherwise) at 24fps, but ultimately, you have to ask yourself what’s best for the subject matter and can be utilized with the budget. More than worrying about frame rate and resolution, studios should be more concerned with the content and general marketing to get people back in the cinema. Frame rate is such a small concern if no one’s even bothering to make it out to the movies in the first place.

  5. mike said:

    Acmada and Mat’s comments uncannily echo the “vinyl is better than CD’ debates of twenty years ago.

  6. Bobby said:

    On the lower-budget and short film end, people have been tripping over themselves in the last five years to shift to 24p production – and, significantly, NOT to 30p. Given the small percentage that are ever output to film, this isn’t just to make conforming easier – the slower frame-rate has an attractive quality. Maybe it’s just because of people’s expectations built on movies seen in theatres, but it *looks* more ‘cinematic’.

    Sports are an interesting example. The first thing a lot of DPs and directors choose to do when shooting a sports scene – cliché though it might be – is to go the other way, to close up the shutter angle and create *more* staccato motion, not less.

  7. Mark said:

    The “cinematic quality” of film is most certainly NOT derived from the 24fps frame rate. Silent film at 18fps still looks cenematic while PAL video at a near-move 25fps still looks chintzy. Anyone who ever sat under ShowScan at 60fps knows it was a FANTASTIC cinematic experience. Flicker and Judder (sounds like a law firm) may be nostalgic, but they are nothing to worship.
    –Mark

  8. Matt G said:

    How do theaters respond is what I wonder. If we upshift the framerate of a movie, will theaters be willing to upgrade? I have a feeling it will take a mainstream film with the higher frame rate to end the debate for certain.

    In whatever case, 24fps will always be around, I’m sure. Just as orchestras have the same basic instruments now that they have had for centuries. Just because something new and pretty comes around, it doesn’t always kill off the predecessor. In the end, the artistry and skill of the film crew has more to do with the beauty of the film than the high definition and motion blurs. These things are simply tools with which to simply succeed or fail.

  9. Alex R. said:

    48 fps would give more of a VIDEO LOOK, which is what most filmmakers want to GET AWAY FROM. Most of the film community agrees that 24fps is the most visually appealing frame rate. 48fps seems like a bad idea.

  10. exelis said:

    Are you people insane? Increase frame rates to 96 fps! We don’t see things in frame rates, why should we be forced to watch them on the screen? I suppose you listen to vinyl LP records for the “warmness” of the hiss and crackle of defects on the disc itself.

  11. Little Donnie said:

    God, if only James Cameron was around 50 years ago! The strobing wagon wheels in Gone With the Wind, the Searchers and High Noon were taking me out of the story!

    Please, 48fps is like taking a photograph of the Mona Lisa instead of painting her. Why don’t we focus on what’s REALLY broken in movies- stories and characters.

  12. AdrenaliNitris said:

    I don’t care about flicker or judder. I care more about the motion blur that 24fps retains. It’s a matter of retaining a sense of reality in the motion. With 24p, there is still enough of a blur to retain the illusion that we are actually looking at a picture in motion instead of a series of pictures displayed rapidly one after another. When the framerate gets too high, the blurs go away. The picture is too crisp, too clear. It starts to look more like stop-motion than authentic motion. That is the key difference between video and film, and that is the real essence of the “film look.”

  13. Chris said:

    48fps will make it look too real. Rather upgrade to 8k resolution than this. It’s just how a film should look, not like a home movie, made with an interlaced cam. That’s what I think, sorry ^_^ For 3D cinema, maybe go to 48frames. I may be only 21, but I feel a little nostalgic when somebody talks about increasing frame rates and changing resolutions (for the worst, anyhow). Leave it the way it is, worked out pretty good so far, hasn’t it?

  14. JP said:

    You probably won’t get animated productions to switch. It’s expensive enough to animate 24fps. You’d effectively double the amount of animating, rendering, etc., which would shoot the budgets through the roof.

  15. AM2Star said:

    24p cameras were developed so that there was a compatability with film. This was the step into film from digital.

    Higher frame-rates will come, just like Todd-AO had half a century ago. Once the technology supports it, it CAN happen. There is nothing to be feared about a higher frame rate, nor appreciated in a lower one, as was mentioned.

    If 4k is the visual limit for film, perhaps the next technology will be a way to merge frames together to generate a transition, not like interlacing but some new style. Perhaps that is the 3D that is being developred.

  16. I think people who are snubbing 48fps should watch a well-made movie in it first. I think Cameron is correct.

    You certainly don’t hear gamers complaining about faster frame rates. Anything under 60fps is considered unplayable these days.

  17. >I think people who are snubbing 48fps should watch a well-made movie in it first.

    Exactly. Without having seen a REAL Hollywood movie (rather than a soap opera) in 48p or even 60p, people should stop playing the shrink here and say that 24fps is that other world that people want to escape to and that’s why 24p is better. You must experience both first, before you can make a comparison. Again, I am not talking about soap operas.

  18. I think at some point somebody has to ask the obvious question. Will doubling the frame rate make a movie more compelling, more emotionally engaging, or even more entertaining?

    Doubt it.

    I personally have many reasons for shooting 24p. I prefer the look over 30p, 60i or 60p. I appreciate the economy of it, because fewer frames per second means less storage and bandwidth required to edit and finish. It’s easier and more economical to light, because a 180° shutter at 24 admits more light than a 180° shutter at 30 or 60.

    But I promise, for whatever their virtues and faults, none of my shows would be any better if I crammed more frames into each second.

  19. Alex…
    Congrats dude, your blog rocks!
    This discussion is getting hot =]

  20. Geoff said:

    JP said
    “You probably won’t get animated productions to switch. It’s expensive enough to animate 24fps. You’d effectively double the amount of animating, rendering, etc., which would shoot the budgets through the roof.”

    That is not true, animated films like Chicken Little have already been re-rendered with double the amount of frames when they converted them to stereoscopic 3D. Converting them to 48fps 2D would be just as easy.

    48fps is the future and solves many of the problems of 24fps, and it’s backwards compatible with 24fps. Directors like Cameron should start shooting in this format and give us an opportunity to buy and see films in this format that has much better temporal resolution, and hopefully other directors will follow, but it doesn’t mean all films have to be in this format. Directors who prefer 24fps can continue using it.

  21. Mikey said:

    Stick with the 24fps for gods sake, am I the only one who feels like I’m watching some amateur home movie when films use 48fps? It may sound cooler to people “cuz 48 must be better than 24 right?” but it looks cheap, amateur and sad when real films use 48, and when they are mixed it just gives the movie a patchwork feel like something thats not finished and was patched together from different things.
    I just got out of “2012” and thought it was a GREAT movie! However like so many movies these days, it had a few scenes that just pissed me off and took away from the epicness of the movie by throwing in scenes with the higher fps, I don’t get why you would patch scenes in like that, anyone who isn’t a moron can see the difference, and its not a good difference.

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