24fps versus 25fps

Ajos

I wish people would stop thinking that shooting at 25fps is acceptable if your film is going to be screened from a print. It's a nightmare. The print will be projected at 24fps. Your film will be 4% longer - that's 4% slower - than you're used to, and that is signifigant. And don't talk about harmonisation as if it's a completely transparent, painless process. A 4% pitch change (without length change) is an incredibly violent thing to do to a piece of sound, no matter how expensive your box. And all your carefully chosen source music will just sound wrong to everybody that's familiar with it. And there's nothing you can do about it.

If you're going to show the film at 24fps, shoot and edit the damn film at 24fps. It is possible! You just need to plan your production and post production path carefully, and work with a sympathetic post house. Unfortunately (and maybe this has changed recently) none of the Dublin facilities want to be bothered working this way - it's easier for them to promote the fiction that shooting at 25fps is a minor compromise.

Honestly, you spend so much time and energy writing, casting, designing, lighting, shooting, editing and mixing your film. You get it as close to the way you want it as you possibly can, down to the minutest detail - a frame here or there on a cut, a dB more or less on a door close. You finish. And then what do you do? You slow it down, randomly. You probably don't even check the new cut (because that's basically what it is), and even if you do check, there's absolutely no possibility of changing anything. Why is that OK?

Sorry. As a sound editor, this particular topic really gets my goat. It matters, people! It matters! And don't record sound on the camera, either. It won't be in sync properly and those cameras can't handle hot levels very well. And there's no confidence monitoring. Double system all the way!

Ranting is fun.

Hugh_C

Originally posted by Ajos


Ranting is fun.

And a little knowledge is a dangerous thing...

I agree about the harmonisation BTW

Ajos

And not about anything else?

Lump

Originally posted by Ajos
I wish people would stop thinking that shooting at 25fps is acceptable if your film is going to be screened from a print. It's a nightmare. The print will be projected at 24fps. Your film will be 4% longer - that's 4% slower - than you're used to, and that is signifigant. And don't talk about harmonisation as if it's a completely transparent, painless process. A 4% pitch change (without length change) is an incredibly violent thing to do to a piece of sound, no matter how expensive your box. And all your carefully chosen source music will just sound wrong to everybody that's familiar with it. And there's nothing you can do about it.

If you're going to show the film at 24fps, shoot and edit the damn film at 24fps. It is possible! You just need to plan your production and post production path carefully, and work with a sympathetic post house. Unfortunately (and maybe this has changed recently) none of the Dublin facilities want to be bothered working this way - it's easier for them to promote the fiction that shooting at 25fps is a minor compromise.

Honestly, you spend so much time and energy writing, casting, designing, lighting, shooting, editing and mixing your film. You get it as close to the way you want it as you possibly can, down to the minutest detail - a frame here or there on a cut, a dB more or less on a door close. You finish. And then what do you do? You slow it down, randomly. You probably don't even check the new cut (because that's basically what it is), and even if you do check, there's absolutely no possibility of changing anything. Why is that OK?

Sorry. As a sound editor, this particular topic really gets my goat. It matters, people! It matters! And don't record sound on the camera, either. It won't be in sync properly and those cameras can't handle hot levels very well. And there's no confidence monitoring. Double system all the way!

Ranting is fun.

Well surely if you balance a mixer tone to 0Db and level the camera at -12Db (Itv Standard) you can balance from your mixer and all is sweet.

John

mycroft

Music will shift down a tone, which is noticable particularly on string instruments. I've seen a performance ruined because a actor had quite a high pitched voice and after the shift it modified the intonation of her lines.

Ajos

Well surely if you balance a mixer tone to 0Db and level the camera at -12Db (Itv Standard) you can balance from your mixer and all is sweet.

It can be done, sure - but what about confidence monitoring? The mixer listens to the output of the mixer, not the camera. If something goes wrong with the cable, or the camerman accidentally changes the level, then there's no way to tell, unless you listen back after every take. I've worked on more than one digital show where there were crucial takes that came up silent or crackly, and if there hadn't been a DAT backup we would have been screwed. In one case we had to ADR a whole scene, which was tough as the actors were semi-improvising and we had to try and lipread exactly what they were saying.

And there's absolutely no headroom. If something goes into the red even a little on the camera, it doesn't distort pleasantly, it makes a giant cracking noise. Hot levels on a DAT (they happen) are sometimes somewhat salvageable - never on the camera. So smart mixers record low, which presents its own problems.

And people tend not to record wildtracks if they don't have a separate recorder, which is a shame.

And it's not proper sync. And it becomes impossible to check, because nobody ever slates. There's an assumption that because it's recorded simultaneously onto the same tape as the video, it's in sync. But it's often not - and it'll be rubbery until the end of time.

And it always sounds slightly compressed to me, slightly MP3ish, although that's controversial. Does anybody know if the sound going on to the camera is true digital 16bit 44.1/48kHz, or something else?

Lump

Wireless headphone return from the camera. I'm just suggesting that it can be done.


John

Ajos

But the cameras never have have confidence, that is to say off tape, monitoring. There's no guarantee that what you're hearing is what's going down. And what about my other points?

I'm not saying it can't be done - it's done all the time. I'm just saying that it's a compromise. It's usually the worst possible option, but it's common because it's perceived as the cheapest. You get what you pay for.

Hugh_C

Originally posted by Ajos
If you're going to show the film at 24fps, shoot and edit the damn film at 24fps. It is possible! You just need to plan your production and post production path carefully, and work with a sympathetic post house. Unfortunately (and maybe this has changed recently) none of the Dublin facilities want to be bothered working this way - it's easier for them to promote the fiction that shooting at 25fps is a minor compromise.

I can think of 4 facilities straight off which will accommodate 24fps. You don't even need the film options on an Avid to do it...

The only reason to shoot at 25, AFAIK, is if you're shooting tape or hi-def.

Ajos

Sorry, yes, I should have been clearer. I meant that it should be possible to work at 24fps while using HD. Isn't that what 24p is all about? That's where the problems come in. But even shooting super 16mm or 35mm on a low budget the post houses will tend to recommend you shoot at 25fps (Halo Effect).

It just seems there's been a flurry of feature films shot on HD at 25fps: Dead Bodies, Ulysses, Headrush, Intermission. (Goldfish Memory and Timbuktu were both also shot at 25fps, but they used mini DV, so I guess there was no option.)

I understand it's a bad idea to try new technology on a big project, but there have been many shorts shot on HD where it would have been perfectly feasible to work out the kinks of the system, but even the people who asked about shooting 24p were told not to. Nobody seems to want to.

Hugh_C

Originally posted by Ajos
Sorry, yes, I should have been clearer. I meant that it should be possible to work at 24fps while using HD. Isn't that what 24p is all about? That's where the problems come in. But even shooting super 16mm or 35mm on a low budget the post houses will tend to recommend you shoot at 25fps (Halo Effect).

Ah, now I understand you... 24p - I just don't know, I have never seen anything @24fps that I know has originated on 24p. I imagine pans look pretty jerky. The maths is astonishingly complicated.

What is Halo Effect?

Ajos

You probably have seen something shot at 24p - any American movie that shoots HD will shoot at that (well, OK, 23.9). There's a list of stuff here that's been recently shot on HD - I'm willing to bet that all or most of these projects were shot at either 24p or 23.9. It's all a lot easier in NTSC, unfortunately. I don't know of any projects that have shot 24p and undergone a PAL postrproduction process, but I don't see why it isn't possible.

And I don't see why the pans would be any jerkier than 16 or 35. Isn't that the point of the "p"? I have seen HD shot at 25fps projected at 24fps, and the pans didn't look particularly bad.

This is the IMDb entry for Halo Effect. They shot on 35mm, at 25fps, because it would be "easier for post". That just ain't right.

Hugh_C

Originally posted by Ajos
YAnd I don't see why the pans would be any jerkier than 16 or 35. Isn't that the point of the "p"? I have seen HD shot at 25fps projected at 24fps, and the pans didn't look particularly bad.

Doesn't that bring us back to the harmonisation argument at the top of the thread, or am I misunderstanding 24p completely?

H

angelofdeath

just got video vegas 4.0 down, looks like a really sweet piece of software, how do you guys rate it?

Ajos

Originally posted by hughchal
Doesn't that bring us back to the harmonisation argument at the top of the thread, or am I misunderstanding 24p completely?

H

This has really gone off topic! Harmonisation as I understand it doesn't have anything to do with image, just sound. I'm not saying that projecting something shot at 25fps at 24fps is a good thing, just that the pans didn't look particularly bad.

I think, and I may be wrong, that the p in 24p, standing progressive, means that the entire frame is captured in one go, as opposed to alternating subframes as in previous video technology. This makes it look more like film, and applies to 25p as well as 24p. Is this right?

I guess I don't really understand why pans should look particularly jerky if they're shot 24p and projected at 24fps, even though the maths is so far over my head it's not even funny.

Hugh_C

Originally posted by Ajos
This has really gone off topic!

snip

I guess I don't really understand why pans should look particularly jerky if they're shot 24p and projected at 24fps, even though the maths is so far over my head it's not even funny.

Yes, but a few comments ago (we should move this onto another topic) you said that you'd seen something like

' I have seen HD shot at 25fps projected at 24fps, and the pans didn't look particularly bad.'

In this case, I wouldn't expect pans to be smooth, but the audio runs at true pitch. The maths is horrible, because basically, in an ideal world, you need to shoot at the lowest rate that has both 24 AND 25 as divisors i.e. 24 x 25 = 600 fps, which is obviously utterly impractical. perhaps there's something lower, but impractical nevertheless. The problem is to stuff 25 pieces of information evenly into 24 slots, which is nasty and therefore, I'm assuming, gives rise to artifacts which manifest themselves as jerky pans.

H

Ajos

Surely the entire problem is that there is no way to harmonise images the way you can harmonise sound - it has to be projected slower because a frame is a frame is a frame (I'm not talking about the way Film Composer or Lightworks can take a PAL project and play it at 24fps, only about the final release format). The 25 video frames per second are transferred 1:1 to film frames, which are then projected as if they were captured at a rate 24 frames per second. So the pans don't look any better or worse than they did on the original medium, just 4% slower. It's nasty because 25 pieces of information are not stuffed into 24 slots - they're stuffed into 25 slots, which equals 1 second and 1 frame rather than just one second.

It is, of course, possible that I'm missing your point.

Ajos

[mod edit] superceded link[/edit]

Dustaz

Sorry for the delay, but im sort of offline atm, but better late than never

Thread split and merged with the new thread.

Hugh_C

Originally posted by Ajos
It is, of course, possible that I'm missing your point.

I probably need to read up on 24p a bit to avoid bullsh1tting any further

hc

Ajos

I'm glad you blinked first!

Ajos

Here's an example of the way the argument can go.

I just think there's a very incorrect assumption prevalent in Dublin (and elsewhere) that the difference between 24fps and 25fps is insignifigant, and it's leading people to make bad decisions about the way they shoot and edit their movies. I'm just trying to be a lone voice in the wilderness. Won't somebody please listen to me! (howls):eek: