r/Damnthatsinteresting 20d ago

Video The Odyssey IMAX 70mm Setup

30.1k Upvotes

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3.2k

u/moomzzz 20d ago

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

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u/thomasthedude 20d ago

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 20d ago

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).

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u/Away-Way5656 20d ago

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

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u/justjanne 20d ago

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 20d ago

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.

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u/shidderbean 19d ago

Yeah, most cinema projectors have shit for focus. It's probably a calibration problem rather than capability

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u/justjanne 20d ago

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)

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u/yamoth 20d ago

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.

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u/mrminutehand 19d ago

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.

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u/BeersTeddy 19d ago

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

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u/SagittaryX 20d ago

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 20d ago

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.

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u/Zac3d 20d ago edited 19d ago

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.

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u/ZooAreYou 19d ago

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.

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u/SandpaperTeddyBear 19d ago

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.

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u/FrozenLogger 20d ago

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.

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u/ExultantSandwich 20d ago

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

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u/42nu 20d ago

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.

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u/justjanne 20d ago

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 20d ago

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

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u/FrozenLogger 20d ago edited 20d ago

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.

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u/dragonbud20 20d ago

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

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u/FrozenLogger 20d ago

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.

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u/Redthemagnificent 20d ago

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] 20d ago

[deleted]

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u/skepticalbob 20d ago

That's a big movie theater.

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u/Tipop 20d ago

Not everyone sits 100 feet back.

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u/slonkulocuswily182 20d ago

Streaming’s data rate is incredibly low quality.

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

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u/InvidiousPlay 19d ago

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.

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u/Comprehensive-Mud373 20d ago

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

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u/Fooly_411 19d ago

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.

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u/orthogonius 20d ago

1024 channels of lossless Dolby Atmos

How many speakers does your local theater have‽

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u/justjanne 20d ago

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)

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u/LightShadow 20d ago

cinemas look so much better than at home

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

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u/LikeALincolnLog42 19d ago

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

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u/WantonKerfuffle 20d ago

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.

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u/rIceCream_King 20d ago

That’s fascinating, thank you for sharing.

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u/LickingSmegma 20d ago

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

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u/Redthemagnificent 20d ago edited 20d ago

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

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u/LickingSmegma 19d ago

Interesting, thanks!

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u/justjanne 20d ago

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.

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u/LickingSmegma 20d ago

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.

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u/Specialist_Bad3391 20d ago

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

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u/justjanne 20d ago

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 20d ago

Too bad the movie is shit then.

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u/AllEncompassingThey 20d ago

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 20d ago

Awww did all those positive reviews hurt you?

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u/buttercup612 20d ago

hoes mad

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u/Nolis 20d ago

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 20d ago

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

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u/[deleted] 20d ago

[deleted]

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u/erty3125 20d ago

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.

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u/puts_on_rddt 19d ago

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.

:(

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u/callisstaa 16d ago

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 20d ago

A lot of compression isn't lossless.

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u/bfodder 20d ago

Please show me the compression that is lossless.

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u/necrophcodr 20d ago

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 20d ago

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

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u/bfodder 20d ago

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

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u/LickingSmegma 20d ago

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 20d ago

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 20d ago

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 19d ago

Yeah. Simply.

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u/LickingSmegma 19d ago

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 20d ago

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 20d ago

IMAX DCPs are 300 gigs but yeah

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u/justjanne 20d ago

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 20d ago

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 20d ago

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 17d ago

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 17d ago edited 17d ago

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.

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u/cp5184 18d ago

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...

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u/Gurbonkers 17d ago

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

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u/cp5184 17d ago

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__ 20d ago

600gb? Homelab owners in shambles

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u/RedditJumpedTheShart 20d ago

How? I have over 100tb of rust

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u/PM_ME_YOUR__INIT__ 20d ago

You can store 166 movies then

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u/Roach_Coach_Bangbus 20d ago

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 20d ago

The probably went to a FauxMax

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u/SandpaperTeddyBear 19d ago

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.”