r/Damnthatsinteresting • u/NoWork215 • Jul 16 '26

Video The Odyssey IMAX 70mm Setup

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3.2k

u/moomzzz Jul 16 '26

Here’s me thinking they just plug in a usb somewhere and crack open VLC player on the big screen

1.1k

u/thomasthedude Jul 16 '26

some cinemas do that, when I went to the latest avatar movie, the audio was out of sync and when they were fixing it you could see they used VLC

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u/justjanne Jul 16 '26

While that can happen (sometimes cinemas can actually get a license to show a movie off a bluray disc), typically there's dedicated playback servers showing a much higher quality version of the movie (think about 600GB for a movie).

105

u/Away-Way5656 Jul 16 '26

what are they doing storing every single frame as a uncompressed image?

316

u/justjanne Jul 16 '26

Pretty much! Every frame is a separate JPEG2000 at almost lossless quality.

That's 10× more data than a typical 4K UHD Blu-ray, with 64 times more color depth than Dolby Vision.

And the sound is for trailers typically uncompressed 5.1 surround, for most movies 1024 channels of lossless Dolby Atmos, or with IMAX lossless 12.1 surround.

e.g. here's a 3 minute trailer in 2048×1080p, aka DCI 2K or 1080p HD, at 3.4 GB filesize: https://archive.org/download/avatar-2009-official-trailer-2k-prores/AVATAR_TLR-B-2D_S_EN-XX_51_2K_20091108_SMPTE_OV.zip

That should give you a feeling for why movies in cinemas look so much better than at home.

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u/retiredalavalathi Jul 16 '26

That should give you a feeling for why movies in cinemas look so much better than at home.

I've never felt that. Picture quality is always crisper on a TV screen than a cinema screen.

8

u/justjanne Jul 16 '26

Interesting!

For me, even Blu Rays will look slightly softer on my OLED at home than in the local IMAX cinemas.

I'm only able to match the crisp cinema look where every piece of film grain is perfectly sharp if I actually play DCP packages at home.

It's possible your cinema is just not up to spec, which is sadly common (and part of why cinema has been dying for almost a century now)

4

u/yamoth Jul 16 '26

That is because the theater screen on average measured 800 inches diagonally whereas most people home TV screen average 65 inches. Same reason why a 1080P youtube video look better on your phone screen vs your 4k 27" monitor.

2

u/mrminutehand Jul 17 '26

Mostly feel the same, though for IMAX in particular. The Manchester Printworks Vue (UK)'s 70mm IMAX presentations usually have film noise or slight blurriness in general, though that's probably more to do with the film itself as opposed to projection quality.

2

u/BeersTeddy Jul 17 '26

Not a rocket science when 85" TV which already shows poor compression in 4k is probably 2m while imax is 22m.

Also the distance from 85" is still labour 3-6m

Whike in cinema you don't really sit 50m aways from the screen

36

u/SagittaryX Jul 16 '26

Compared to streaming yes, that's a noticeable difference to quite a few people. But I doubt that if you played that quality vs a 4K BluRay on the same screen that there is that huge of a difference that people would notice.

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u/VexingRaven Jul 16 '26

Of course, but that's the point right? They're not playing it on an 85 inch screen. They're playing it on an 85 foot screen. It needs to be perfect.

9

u/Zac3d Jul 16 '26 edited Jul 17 '26

It needs to be perfect.

Last time I went to the movies the projector screen was dirty. Which meant the brighter the image, the more apparent any flaws in the screen were. And also the black levels for projection just sucks compared to a modern OLED. Flaws of a theater are more apparent than what Blu-ray compression would be.

2

u/ZooAreYou Jul 17 '26

Theres one cinema we go to where some prick clearly threw a milkshake at the screen and apparently the cost to clean it is somehow too much for the cinema to bother with. As you say its noticable in bright scenes. Its like an infuriating dead pixel once you know about it.

2

u/SandpaperTeddyBear Jul 16 '26

It truly doesn’t matter, because you’re sitting so much further from the 85 foot screen.

My understanding of the development “HD” format is that it was more or less designed to be similar to sitting in the middle of a movie theater watching a normal screening print. My experience of having watched movies off of a 35 mm projector for many years, followed by some years of watching standard blu rays get sometimes played in movie theaters, is that they got it about right.

The one exception is well-shot black and white movies, which have much more dynamic range than the HD blu ray format allowed for, but 4K UHD discs are basically reference quality even for those.

5

u/FrozenLogger Jul 16 '26

Or just good enough. I haven't been able to find a theatre that gave a shit in years. Even IMAX.

Looks better at home.

14

u/ExultantSandwich Jul 16 '26

Have you actually been to an IMAX theater? The US has 14 screens, NYC has exactly one. California has two for the entire state

3

u/42nu Jul 16 '26

Wait, are we talking the IMAXs that are a giant dome and more likely to be part of a science museum?

I could see there only being 14 of those in the US.

8

u/justjanne Jul 16 '26

IMAX is a weird, overloaded term.

There are only 41 IMAX film cinemas in the world (which are also the ones showing the Odyssey on film).

There are hundreds of IMAX Laser cinemas, which often also have the same aspect ratio, same size screens, and just slightly less sharp image.

And then there's all the shitty cheap regular cinemas that have an IMAX label attached but did nothing to earn it.

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u/LeedsFan2442 Jul 16 '26

There are very few cinemas that are truly IMAX and actually use 70mm film projectors

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u/FrozenLogger Jul 16 '26 edited Jul 16 '26

Yep, many times actually. The angle of the seating and size of the screen is the amazing part. But it seems like the quality of those isnt what they used to be.

Funny thing about IMAX, is they are not all the same. They really should be if they are marketed as IMAX.

3

u/dragonbud20 Jul 16 '26

You're either partially deaf, partially blind, or you've never been to a real IMAX theatre with an actual 70mm projector.

-1

u/FrozenLogger Jul 16 '26

OR enshitification is everywhere, i have a great home system, my viewing angle is perfect, the screen is kept clean and my proximity matters.

Again, been to many IMAX theatres they are not all the same, but even the best ones just dont impress me that much.

But speaking of 70mm, that used to not be an uncommon format. Approx 150 theatres in the US in the 60's and 70's. Nowdays it is mostly IMAX.

There was a LOT lost by creating all these dinky little movie boxes that are everywhere today. IMAX at least makes up for that.

Well at least the ones that actually are 70mm. A lot of IMAX are not. Scammy little company.

1

u/Redthemagnificent Jul 16 '26

I agree with 90% of movies. But a properly mastered IMAX movie is legitimately a different experience. Every once and a while I think it's worth it

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u/[deleted] Jul 16 '26

[deleted]

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u/skepticalbob Jul 16 '26

That's a big movie theater.

11

u/slonkulocuswily182 Jul 16 '26

Streaming’s data rate is incredibly low quality.

The picture relies on your tv/phone to sharpen the image.

2

u/InvidiousPlay Jul 17 '26

That's not correct at all. Most devices do very little on the fly "sharpening"; it's not an effective strategy anyway, you can't magic away compression artifacts.

Compression algorithms are just extremely efficient at keeping half-decent images even at awful bitrates.

10

u/Comprehensive-Mud373 Jul 16 '26

Yeah, why like have different quality on video at all? What's the reason of having 2160p 4K when 480p is more than good enough on my phone? /s

1

u/Fooly_411 Jul 17 '26

I bet you would easily notice the difference on a large theater screen in the dark. There is a vast gulf of what is noticable to the eye with that set up vs even high quality TV panels.

2

u/orthogonius Jul 16 '26

1024 channels of lossless Dolby Atmos

How many speakers does your local theater have‽

1

u/justjanne Jul 16 '26

Most cinemas have usually something like 64 actual speaker channels, but that's the point of Atmos (or DTS:X), object-based surround sound automatically mixed for whatever speaker configuration the local cinema has.

(In contrast to the old times, when cinemas had 5.1 channels with 5-10 speakers per channel)

2

u/LightShadow Jul 16 '26

cinemas look so much better than at home

Only if the projector is in focus...which is a real problem around here.

2

u/LikeALincolnLog42 Jul 16 '26

The movies at my local AMC look like total shit unless you’re in one of the only two big auditoriums. The other 14 screens are complete and utter crap. They’re unbelievably dim, and no amount of polite complaints to the local staff or via their website has resolved it. Thanks, AMC! /s

2

u/WantonKerfuffle Jul 16 '26

So that's what it takes to squeeze the maximum amount of quality out of our current technology.

...only for me to go "wow that is uncomfortably loud" as my main takeaway comparing the cinema experience to a BD at home.

1

u/rIceCream_King Jul 16 '26

That’s fascinating, thank you for sharing.

1

u/LickingSmegma Jul 16 '26

The hell are you gonna do with 1024 audio channels? Are you mixing them with 1024 sliders, with near-analog precision?

3

u/Redthemagnificent Jul 16 '26 edited Jul 16 '26

Its done with software using object-oriented sounds in 3D space. "dolby atmos" is one example of such software.

The idea is you want the your explosion sound or whatever to sound like it's coming from the same direction with the same volume in every theater no matter what the speaker configuration is. So instead of a fixed master track tuned to a specific speaker layout, the audio system gets a command saying "make this sound come from XYZ coordinate in your theater" and it does some processing in realtime to figure out the exact volume and timing (phase) each speaker needs to use to fullfil that command.

To come back to your question on the number of channels, that defines your maximum resolution. More channels = more precise beam forming. Idk about the 1024 number. That does seem to high to me. But idk, it's possible. Audio processing is cheap these days

1

u/LickingSmegma Jul 17 '26

Interesting, thanks!

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u/justjanne Jul 16 '26

Basically, once you go beyond 12.1, each cinema will have a different speaker configuration.

So instead you have each individual object as a separate track, in the scene positioned in 3D space, and typically a Dolby Atmos processor that then mixes that automatically for the specific speaker configuration of each cinema.

2

u/LickingSmegma Jul 16 '26

So indeed pretty much close to what I was imagining. Except hopefully you just specify how your speakers are positioned in some kinda virtual room, and the thing calculates the mix itself.

This must be a nightmare for the studio's audio engineers too. I'm gonna guess most films don't use anywhere near the whole 1024 channels.

1

u/Specialist_Bad3391 Jul 16 '26

All that and then you have an uncalibrated projector with chromatic aberration all over the picture. Totally skewed and flickering luminosity.

That's where I saw backroom. At least half the time there was a vhs look over the image so the poor image quality wasn't so important. But come on, if I'm paying 15 for a 2h screening theater better up their rig

1

u/justjanne Jul 16 '26

And if you're in a non-english country, the sound is often also dubbed.

There's a reason why I only watch movies either in IMAX with Laser 4K in the original language, or at home (with an OLED and proper Dolby Atmos 5.1.4 system, not a soundbar).

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u/piss_puncher227 Jul 16 '26

Too bad the movie is shit then.

8

u/AllEncompassingThey Jul 16 '26

I feel like when you bought a ticket to The Emoji Movie you knew what you were getting into

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u/GloriousNewt Jul 16 '26

Awww did all those positive reviews hurt you?

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u/Nolis Jul 16 '26

Usually the contrarians who just sort by top to find a bunch of movies they've pretended they've seen and pretend they don't like at least try to copy and paste points they've seen from negative reviews online, it's funny that you guys just literally can't find any for this movie lol

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u/daninet Jul 16 '26

Its Jpeg2000 compression with uncompressed audio. Video is around 500mbps

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u/[deleted] Jul 16 '26

[deleted]

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u/erty3125 Jul 16 '26

That's not uncommon still, a lot of games the majority of the game size is in audio and video files still, for a while it was a not uncommon process to delete other languages + story mode voice files + other languages in games to make the file size drastically smaller.

2

u/puts_on_rddt Jul 17 '26

As a consumer, the best quality of movies I can buy is the 4K UHD version. If I rip it losslessly to my PC I usually end up with a 60gb file that has a bitrate of 60Mb/s.

They get 10x that.

:(

1

u/callisstaa Jul 20 '26

Same with PS1 games. CDs were about 600MB and even at 420p FMVs and mp3 audio used the bulk of that space, hence why FMV heavy games like Final Fantasy came on multiple disks.

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u/necrophcodr Jul 16 '26

A lot of compression isn't lossless.

-1

u/bfodder Jul 16 '26

Please show me the compression that is lossless.

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u/necrophcodr Jul 16 '26

Well general compressions are. I don't know of any video compressions that are lossless, but I don't claim to know everything.

Edit:

Apparently there's quite a few: https://en.wikipedia.org/wiki/List_of_codecs#Lossless_video_compression

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u/LickingSmegma Jul 16 '26

FLAC, APE or WavPack for audio (in fact, iirc even WAV uses basic run-length compression). PNG or lossless Webp for static images.

1

u/bfodder Jul 16 '26

I guess I should have said video compression because that was what I was meaning, but it seems those do exist anyway.

1

u/LickingSmegma Jul 16 '26

Well, if you simply encode each frame as lossless webp, you already get lossless video compression.

FLAC and other lossless audio codecs apply pure mathematical compression that allows reconstructing the original stream, only they account for playback realities such as seeking. It's no surprise that the same can be done with video.

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u/justjanne Jul 16 '26

Technically™, webp is the worst format to use for this comparison, as it always converts to YUV in 4:2:0 and sRGB.

But assuming we go with e.g. cinemaDNG, that's exactly how lossless raw compression works.

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u/LickingSmegma Jul 16 '26

Yeah, I keep discovering that people have come up with lots of niche image formats in the past fifteen or so years when I wasn't actively looking at them (and, to a lesser extent, audio formats too).

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u/bfodder Jul 16 '26

Yeah. Simply.

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u/LickingSmegma Jul 17 '26

I mean, that's how animated GIF works in its simpler form. Every frame is a separate static GIF. It allows for some additional compression by replacing unchanged areas with the 'transparent' color, which gets compressed just like other areas of the same color.

I need to look into APNG, it might be a more advanced version of the same idea.

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u/chocolateboomslang Jul 16 '26

Well, yeah. If we're paying money to see a movie in the movie theatre we should expect the best quality they can deliver.

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u/Gurbonkers Jul 16 '26

IMAX DCPs are 300 gigs but yeah

1

u/justjanne Jul 16 '26

Is that maybe for the 2K dual projection systems, or for movies with more typical runtimes? Because the previous 3h movie 4K DCPs I've seen were around 500-600 gigs.

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u/Loraelm Jul 16 '26

Yeah but you weren't specific about the 3h part lol. A regular 90min movie is around 350 Go in 4K

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u/justjanne Jul 16 '26

Ah, sorry :D I thought it was obvious with the original post being about Christopher Nolan's Odyssey, but I should have been more clear about it.

Have a nice evening :)

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u/Gurbonkers Jul 19 '26

No. Odyssey’s DCP is 300 gigs. There are pictures. The largest DCP in history so far is the no way home DCP which was 500 gigs cause it was 3D

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u/justjanne Jul 19 '26 edited Jul 19 '26

Could you please link the pictures then?

The known trailer DCPs are:

  • Trailer Normal FLAT 2K, 2.39:1:1 3.1GB
  • Trailer IMAX 4K 1.43:1 10.8GB

The known movie DCPs are:

  • Standard FLAT 4K 299GB
  • Standard SCOPE 4K 297GB
  • Dolby Cinema FLAT 4K 216GB
  • Dolby Cinema SCOPE 4K 214GB
  • Barco FLAT 4K 442GB
  • Barco SCOPE 4K 439GB

Both from extrapolating the trailer sizes, and from extrapolating the pixel count of the different releases, you'd expect the IMAX 1.43:1 DCP to be around 500GB.

1

u/cp5184 Jul 18 '26

8k imax must be huge... Looks like just a normal 8k dcp would be about 17TB raw, ~8.5TB losslessly compressed... plus, like 10GB probably for sound or so?

imax often does double camera so it may be 34TB/17TB? And if they mess around with 60fps... 85TB...

1

u/Gurbonkers Jul 19 '26

Wtf are you talking about? They don’t do DCPs in 8K

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u/cp5184 Jul 19 '26

Why not?

Warner Bros said that it has scanned around 20 films in 8K in recent years. Each film is scanned at 4K or 8K depending on the visible difference,

Samsung to showcase 8K movie trailers for Creed III, Barbie, Blue Beetle, Dune: Part Two, Wonka and Aquaman and the Lost Kingdom

https://www.flatpanelshd.com/news.php?subaction=showfull&id=1745480457

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u/PM_ME_YOUR__INIT__ Jul 16 '26

600gb? Homelab owners in shambles

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u/RedditJumpedTheShart Jul 16 '26

How? I have over 100tb of rust

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u/PM_ME_YOUR__INIT__ Jul 16 '26

You can store 166 movies then

1

u/Roach_Coach_Bangbus Jul 16 '26

I read they receive hard drives that have the movie on it? Regal has been doing a ton of older movies on and off since September. I remember the day they were supposed to show Saving Private Ryan got delayed because they didn't receive the hard drive in time.

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u/Inquisitive_idiot Jul 16 '26

The probably went to a FauxMax

1

u/SandpaperTeddyBear Jul 16 '26

sometimes cinemas can actually get a license to show a movie off a bluray disc

And sometimes they just don’t care.

Also, it’s possible that some theater rentals for normal birthday parties and stuff fall under “exhibition” laws, but in practice I doubt studios care, and those are usually “bring your own blu ray.”

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u/DefMech Jul 16 '26

That doesn't sound right. The system for digital movie distribution is heavily locked down and tightly integrated with the studios themselves, to the point that the actual theaters barely have any control over showtimes and when/how a movie starts. I'm not sure how a theater would be able to play a new release digital movie through VLC. Movies released in DCP are encrypted and to my knowledge there is no way to acquire the keys or decrypt the files unofficially.

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u/justjanne Jul 16 '26

They probably used VLC for the trailers, or in some rare cases cinemas can also get a license to play movies off of consumer blu ray discs, but that's typically only for films that have long been released.

Sometimes you can get decrypted DCPs, and especially trailers are never encrypted — e.g., here's the Avatar (2009) trailer as DCP https://archive.org/download/avatar-2009-official-trailer-2k-prores/AVATAR_TLR-B-2D_S_EN-XX_51_2K_20091108_SMPTE_OV.zip

But VLC doesn't properly support DCP anyway.

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u/FrenchFryCattaneo Jul 16 '26

Yeah I've seen small theaters where the ads before the movie are played on a completely different projector, so that could be done on vlc.

3

u/justjanne Jul 16 '26

Even the proper cinema projectors usually have an HDMI input.

In larger cinemas you'll typically see one set of ads (usually local businesses, car ads, ice cream, etc), then a few seconds of darkness, followed by movie trailers and maybe one or two ads. The first half is usually played from regular video files such as .mp4, while the second half are actual cinema packages (DCP). Often the first half is played from a different projector or via the HDMI in.

1

u/excaliburxvii Jul 17 '26

So how the hell am I supposed to watch that trailer? Genuinely, I would like to. MPC? Whatever Linux equivalent?

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u/justjanne Jul 17 '26

The intended way: with a cinema projector. They have DCP playback servers builtin.

MPC and MPV won't work either, they also just use ffmpeg (the library that powers VLC) and have a different UI on top.

Alternatively, easyDCP or doremi might work for you.

0

u/excaliburxvii Jul 17 '26

Oh darn, those are expensive. Understandably. My hopes of seeing that original Avatar trailer in glorious quality, not obliterated by 17 years of compression are dashed. :(

Thank you for the info. I assume that, hypothetically, even with a DCP server or something like easyDCP there aren't really DCPs to watch for a normal (non-rich) person? Just curious.

2

u/justjanne Jul 17 '26

I don't think there are any good solutions.

But there is a ProRes version, which is minimally compressed, but with slightly worse color than the actual DCP.

https://archive.org/download/avatar-2009-official-trailer-2k-prores/AVATAR_TLR-B-2D_S_EN-XX_51_2K_20091108_prores.mov

1

u/excaliburxvii Jul 21 '26

Thanks for the link, and the info.

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u/Caboose127 Jul 16 '26

Most likely scenario is that they don't live in the USA (or a country with formal distribution channels for movies) in some smaller countries it's very common for theaters to show bootleg copies of movies.

This won't happen in the USA though (or at least if it does happen, the theater won't stay on business very long).

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u/fascfoo Jul 16 '26

I'm wondering if this "theater" this person went to was some janky bootleggy place

1

u/Nauin Jul 16 '26

Do... Do you not live somewhere dense enough for there to be an indie theater? Because indie theaters have a lot of freedom compared to your standard corporate chain while still getting a select few new releases.

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u/curtcolt95 Jul 16 '26

they don't get to play by different rules just because they're not a big chain

1

u/chocolateboomslang Jul 16 '26

Allow me to inform you of something called "breaking the rules"

2

u/DefMech Jul 17 '26

How would they do that in this scenario? When Avatar was released, there was no ability then or now to access the unencrypted DCP files to be able to play the movie through VLC. You can certainly do it now after the movie has been out on streaming and DVD/Blu-ray. It's trivial to play a pirated or legit copy of the movie, but definitely not when it was originally released in theaters.

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u/chocolateboomslang Jul 17 '26

I'm assuming it was a bootleg copy some time after the release. Not a day one release.

2

u/shodan13 Jul 16 '26

Not even MPC? smh

2

u/symphonicrox Jul 16 '26

They do basically download the movies now, but they have to play at such a high bitrate. Many theater-quality movies are essentially 1080P, but because of the bitrate they are so much better.

1

u/cletusthearistocrat Jul 16 '26

We went to a theater to watch Wonka (2023) and it looked and sounded exactly like a cam pirated copy. Low resolution, flat color, terrible echoey sound. It was such poor quality that we walked out. (And this was at a big national chain.)

Went home and searched the internet for a way to watch the movie with better quality and found the movie with the exact same shitty quality as the theater. Waited a couple of months and were able to finally watch the movie with the "good" quality.

I'm quite positive that the theater pirated the movie instead of paying for it. Has anybody heard of or experienced this?

1

u/Ninja-Sneaky Jul 16 '26

Here is this article from Artechnica in 2016: https://arstechnica.com/gadgets/2016/05/cannes-film-festival-digital-cinema-system-details-photos/

They describe the setup at Cannes Film Festival, fully digital with this quote:

Then you have the playback computer, which, at least at Cannes, is just a computer running something akin to VLC.

1

u/justjanne Jul 16 '26

If you actually read the article, they go into a lot of detail on how decryption, delivery, and software like doremi work.

And how these players automatically handle ads, trailers, curtain motors, lights, intermissions, etc.

1

u/Stained_concrete Jul 16 '26

Top tip: Hit J and K to nudge the audio back and forth while VLC is playing without leaving fullscreen.

1

u/DazzlingRutabega Jul 16 '26

I definitely figured they moved to something digital after all the cinemas revamped for high death. It's hilarious that they use VLC.

Also, I remember back in the day the girl I went on a date with to go see The Matrix had seen it before but she said she was fine seeing it again.

In the scene where Cypher betrays Neo suddenly the film literally melted onscreen. The theater got it back up and running quickly, however it was after all the action happened and the scene played out. I freaked out wondering what I missed and then remembered that my date had seen it before and luckily she filled me in on what happened. It was kind of worth missing that scene because I had never seen that happen in a movie before (and now probably never will again).

1

u/Alienhaslanded Jul 17 '26

Just put that on Pirates Bay.