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James Cameron champions faster film projection rates (from 24 to 60 fps)

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Re: James Cameron champions faster film projection rates (from 24 to 60 fps)

#71

Post by jwr »

alexqgb wrote: post #51
bpeebles wrote: post #33

Earlier quoted context omitted.

48 divides evenly into 240, so in theory a 240Hz TV could take a 48Hz signal and display it without any pulldowns, while 120Hz is 2.5 times 48, so it needs to do some work to create extra frames. (And really, that's the main advantage, currently, of 120Hz and 240Hz: 24, 30, and 60 (the primary American frame rates) all divide evenly into them, unlike 24 into 60).

Seems like you wouldn't count on the TV to do this work. Instead, you'd shoot at 48, then convert to 60 before delivery, in the same way that TV shows shot on film and edited at 24p subsequently convert to 25 for PAL markets and 29.97 for NTSC.

Problem is, while you can devise ways of converting 24p to interlaced 29.97, getting from 48 progressive frames to 60 progressive frames isn't obvious to me at all. You'd have to add a frame every 4 frames. This would likely ruin the whole large framerate experience.

Re: James Cameron champions faster film projection rates (from 24 to 60 fps)

#73

Post by jwr »

alexqgb wrote: post #66
masuel wrote: post #61

Earlier quoted context omitted.

H264 has no such limitation regarding gop structure. The levels (3.0, 4.1 etc) define (slightly indirectly) the DPB (decode picture buffer) size. This is how many frames must be held in memory at one time. The gop itself is not limited. Furthermore the compression rate for high frame rate actually increases for live action as there has been less change between the frames and even taking a fixed framerate. There are c…

Very interesting. Thanks for the detail. I guess the fixed GOP structure must be limited to HDV (MPEG-4). That flexibility is pretty awesome. For what it's worth, I suspect what you describe (720p60 @ 6Mbps) is more than fine for most people. In other words, Cameron's idea that people will be going to theaters because of magical picture quality seems like wishful thinking. I suspect people go to theaters because they…

HDV has nothing to do with H.264, or any of the MPEG-4 standards for that matter.

Re: James Cameron champions faster film projection rates (from 24 to 60 fps)

#74

Post by jwr »

alexqgb wrote: post #58
jwr wrote: post #27

Notice he's leaning towards 48p as opposed to 60p, which is an already standardized framerate that your modern TV likely supports. I do not think that is an accident. After all, once we all buy our new 3D TVs, something will have to happen for people to buy new TVs again in 3-4 years. And before you mention bandwidth considerations, I do not have actual data, but I suspect that when using H.264 High Profile, the diff…

Assuming the bitrates are the same, 48fps will require 80% of the bandwidth needed to handle 60. To the best of my knowledge, H.264 only supports two GOP structures (short = 6 frames / long = 15 frames), both of which operate independently from the playback speed. In other words, a short GOP setting produces 8 blocks per second running at 48, and 10 per second running at 60. Assuming a constant bitrate (I know, I kno…

> "To the best of my knowledge, H.264 only supports two GOP structures (short = 6 frames / long = 15 frames), both of which operate independently from the playback speed. In other words, a short GOP setting produces 8 blocks per second running at 48, and 10 per second running at 60. Assuming a constant bitrate (I know, I know), the throughput of the entire system needs to increase by an additional 20% to handle 60."

I'm sorry, but it needs to be stated: the above isn't true and the calculations have nothing to do with reality. H.264 supports pretty much any GOP structure and you don't get from frames to final bitrate by dividing frame rates by GOP size.

Re: James Cameron champions faster film projection rates (from 24 to 60 fps)

#75

Post by mryall »

relix wrote: post #18
VMG wrote: post #2

This is more exciting for me than 3d. I remember thinking this when I first noticed that counterstrike didn't feel right at <60fps while watching action films with 24fps

That is because a game's frame is rendered at one absolute time point, while a movie's frame is like a photograph taken with a shutter speed of 1/24th: it includes the motion data of that whole time interval, it contains motion blur, and it's smooth from one frame to the next. That's why a game at 24fps looks bad, but an (action) movie at 24fps looks good.

That doesn't seem like it could be true. The film is rolling through the camera, and if the shutter were open continuously, the entire film would be a vertical blur of light. The shutter would open and close once per frame, so the film can be advanced. The actual shutter speed of a camera shooting 24 fps would be much faster than 1/24 s.

Re: James Cameron champions faster film projection rates (from 24 to 60 fps)

#76

Post by VMG »

jonhohle wrote: post #41
DanielBMarkham wrote: post #12

My idea of great film tech? 8K, 60fps, and true 3-D (not the hokey 2-level thing) It'd be awesome, but it's a long, long way away. As Jim says, this is low-hanging fruit. Easily done with most everything that's on the shelf today.

It may be low hanging fruit, but imagine rotoscope work on a 24fps feature vs a 60fps feature. The work has just increased 2.5x for the same shot. For fully rendered content, there is likely no additional man hour time, but for any frame by frame work involving humans, post processing could take a lot longer.

Is this kind of thing really done frame-by-frame though? I think with smart interpolation techniques you shouldn't have to do single frames anymore.

Re: James Cameron champions faster film projection rates (from 24 to 60 fps)

#77

Post by ciupicri »

seanalltogether wrote: post #31
modeless wrote: post #7

The problem is that 24 FPS is now part of the Hollywood "look". 24 FPS is associated with high quality high budget productions in people's minds; 60 FPS looks like a home movie or low-budget TV sitcom. It may take a while to change people's perceptions.

Sitcoms and soap operas look the way they do because of lighting. I won't disagree that 24 fps has something to do with the 'film' look, but I think camera lens, filters, and lighting affect the look of the movie more then the framerate.

I have always asked myself why films made for television look different than the ones made for cinema. Thank you for the explanation!

Re: James Cameron champions faster film projection rates (from 24 to 60 fps)

#78

Post by RVK »

electromagnetic wrote: post #65
modeless wrote: post #7

The problem is that 24 FPS is now part of the Hollywood "look". 24 FPS is associated with high quality high budget productions in people's minds; 60 FPS looks like a home movie or low-budget TV sitcom. It may take a while to change people's perceptions.

No, the Hollywood "look" is having tens/hundreds of millions of dollars to dump. TV looks low-budget because it is low budget. But there's a big difference between real low budget TV and simply TV. Honestly, download an original British or Canadian drama show that doesn't get carried in the US and you'll see low budget. You'll see horrific, unwatchable direction. I'm sorry, but give Sam Raimi a video camera with any…

I can't speak for Canadian TV but primetime British dramas are generally technically excellent - for instance, this year's Oscar winner for Best Director, Tom Hooper, has directed episodes of Cold Feet, EastEnders and Byker Grove.

Practically nothing that doesn't feature US accents and locations is picked up by the networks - sometimes period co-productions sneak in, as long as there's pretty frocks and no swearing.

You're missing Misfits, for instance, which is the best show on TV...

Re: James Cameron champions faster film projection rates (from 24 to 60 fps)

#79

Post by byw »

modeless wrote: post #7

The problem is that 24 FPS is now part of the Hollywood "look". 24 FPS is associated with high quality high budget productions in people's minds; 60 FPS looks like a home movie or low-budget TV sitcom. It may take a while to change people's perceptions.

I think the fact that Cameron, Jackson, and Lucas are using it will make the transition much easier.

Re: James Cameron champions faster film projection rates (from 24 to 60 fps)

#80

Post by nathos »

mryall wrote: post #75
relix wrote: post #18

Earlier quoted context omitted.

That is because a game's frame is rendered at one absolute time point, while a movie's frame is like a photograph taken with a shutter speed of 1/24th: it includes the motion data of that whole time interval, it contains motion blur, and it's smooth from one frame to the next. That's why a game at 24fps looks bad, but an (action) movie at 24fps looks good.

That doesn't seem like it could be true. The film is rolling through the camera, and if the shutter were open continuously, the entire film would be a vertical blur of light. The shutter would open and close once per frame, so the film can be advanced. The actual shutter speed of a camera shooting 24 fps would be much faster than 1/24 s.

Correct. There's a simple formula for that: http://en.wikipedia.org/wiki/Shutter_speed#Cinematographic_s...
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