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How encryption for Cinema Movies works

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Re: How encryption for Cinema Movies works

#91

Post by dvngnt_ »

codemiscreant wrote: post #24
john01dav wrote: post #3

Even with all of this onerous encryption and DRM, it's not hard to find pirated copies of movies. It makes me think that the sacrifice in ownership rights for the theaters over their equipment isn't worth it.

There is essentially zero piracy from these digital cinema releases. The pirate copies are generally from once it starts digitally streaming on one of the services including PPV, and when pirate copies exist earlier it is almost always someone with a camera in a theatre making a terrible quality screener. Piracy is inevitable, but in this case their model is much more robust that I would have predicted.

Back in my day the first releases were cam rips sold on dvds for $3-5 per movie. quality wasn't great but the audio could be ripped from the devices for hearing impaired https://en.wikipedia.org/wiki/Telesync

quality varied but was good enough in mid 00's probably better

Re: How encryption for Cinema Movies works

#92

Post by asdcplib »

Hi, asdcplib author here (mentioned in the article.) Excellent writeup of DCP and related tech. FYI the colorspace of an SDR DCP MXF file is X'Y'Z' with gamma 2.6 (see SMPTE 428-1.) Other MXF formats (i.e., not cinema) use a wide variety of colorspaces. Despite the huge range of XYZ, DCP image files are usually constrained to code values that fall within P3 (again, SDR.) The HDR applications are more interesting.

Upon reading the comments: • DCP is a B2B format. DCP usage is licensed by contract, not EULA. Please keep these important differences in mind when commenting on DRM. • Decrypt, decode, color processing, watermark occurs in FPGA. If you think that sounds hard, remember that all of this tech was originally deployed 20 years ago. Moore's law has made our lives much easier since! • Frame-by-frame encipherment, rather than whole stream, better supports random access and the famous tobacco intermissions popular in the EU.

Re: How encryption for Cinema Movies works

#93

Post by crazygringo »

kelnos wrote: post #34
codemiscreant wrote: post #24

Earlier quoted context omitted.

There is essentially zero piracy from these digital cinema releases. The pirate copies are generally from once it starts digitally streaming on one of the services including PPV, and when pirate copies exist earlier it is almost always someone with a camera in a theatre making a terrible quality screener. Piracy is inevitable, but in this case their model is much more robust that I would have predicted.

Not sure of the GP's core message there, but I think this is kinda the point: even with all this onerous encryption on the cinema releases, high-quality pirated copies still very quickly make it out. So basically they have this very secure scheme for getting movies to theaters, but everything else is full of holes. Makes you wonder if all the effort and cost to secure the theater distribution chain is worth it. If yo…

> Certainly this does make the case of a theater-only-first release nearly impossible to pirate. But there aren't quite as many of those anymore, and all this DRM must be expensive, both in the hardware/software, and in the logistics. I guess they've found it's worth it, but... oof.

Yes, that's the entire point. There are still tons of theater releases, that's literally the entire business of cinemas. The cost of DRM is peanuts next to their revenue, it's absolutely worth it to them. Nothing "oof" about it.

Re: How encryption for Cinema Movies works

#94

Post by crazygringo »

fulafel wrote: post #56
userbinator wrote: post #36

Earlier quoted context omitted.

Dedicated hardware, not even regular GPUs. JPEG2000 decompression has a rather complex entropy decoding part which is not easily parallisable.

Only on the intraframe level - Frames are independent so overall it's "embarrassingly parallel".

There's no point to decoding in parallel if you're watching in sequence.

Re: How encryption for Cinema Movies works

#95

Post by alabastervlog »

loeg wrote: post #46
plastic3169 wrote: post #44

Earlier quoted context omitted.

There are no high quality pirated versions though. The streaming version and even blu-ray is compressed way heavier than these DCP files. I’d buy these cinema versions of films in a heartbeat if they were availble.

1080p/4k as encoded by the streaming sites / blu-ray is sufficiently high quality for virtually all of the viewing public. You're weird (no offense).

Even among the set of people who have something even semi-resembling a proper home theater—which is already a tiny group—I'd be 95+% would need to upgrade their gear quite a bit before they'd benefit at all much from quality higher than ~50GB-100GB blu ray rips.

(stream rips do often does look like dog shit, though—I find sub-10GB 1080p blu-ray downscales [to get the HDR from the 4k blu ray, but lower res and storage space] usually look better than raw 4K streaming rips)

Re: How encryption for Cinema Movies works

#96

Post by mysteria »

kmeisthax wrote: post #47
mysteria wrote: post #20

Earlier quoted context omitted.

To be clear, traitor-tracing each stream would require a unique encode per account to inject the stegotext; that's computationally unfeasible. Doing one encode per movie theater would still be a struggle, but less so by three orders of magnitude. If the movie is streamed in chunks, only certain short segments would need to be reencoded to add watermark data. Alternatively it might be possible to splice in a short seg…

If you were only watermarking short sections of the video, wouldn't that make it possible to analyze the stegotext and erase it? You could have a handful of people rip the same video and then compare them, and if different sections get watermarked then you can reassemble an unwatermarked file. This also applies to splicing in short segments of watermarked video. If you have the whole thing watermarked then all you ca…

Sectional watermarking is always going to have a higher risk of detection using multiple rips but that's the tradeoff you get with computational power. As you said the best option is to watermark the whole thing but that's expensive.

Cinavia looks interesting as it's done on the client side, like how programs like Photoshop detect the watermarks in banknotes to prevent people from using it to create forgeries. If they managed to get it into the firmware of every television, AVR, etc. then it would be much more effective than just having it on Blu Ray players.

Re: How encryption for Cinema Movies works

#97

Post by alabastervlog »

Mindwipe wrote: post #77
ajsnigrutin wrote: post #11

Earlier quoted context omitted.

Yes, and those paid options were one subscription that had "everything". Then paid options broke up into 5 different subscriptions, some not allowing more than 2 devices, some having ads in paid plans, some not available in your country, some only having seasons 3 and 5 of the series, some having the series you wanted to watch but remove it half way through, some give you a "buy" button for the media, but then take t…

> Yes, and those paid options were one subscription that had "everything". It really didn't. It's incredible this collective delusion exists when it's not true.

It was a lot closer when they still had a streaming + disk option, but even then, they were missing lots (and lots, and lots) of stuff. I think people don't realize how many tens of thousands (maybe into the hundreds, IDK, I wouldn't be surprised) of films there are, let alone how many hours of TV content.

This is like when people talk about how everything's on the Web, when it comes to books. 1) This is only even sort-of true if by "on the Web" you mean "piracy sites have an epub/pdf of it", and 2) even then, extremely not close to true, the time from "I'm going to deep-dive this topic" to "... and now I need to go to the library, and possibly a specific library, maybe on another continent" is often not long at all.

Re: How encryption for Cinema Movies works

#98

Post by dsr_ »

crazygringo wrote: post #94
fulafel wrote: post #56

Earlier quoted context omitted.

Only on the intraframe level - Frames are independent so overall it's "embarrassingly parallel".

There's no point to decoding in parallel if you're watching in sequence.

If your hardware can only manage 4 frames per second but you need 48, then decoding with 12 sets of hardware in parallel achieves your goal.

Re: How encryption for Cinema Movies works

#99

Post by wmf »

jasode wrote: post #68
kelnos wrote: post #34

Earlier quoted context omitted.

Not sure of the GP's core message there, but I think this is kinda the point: even with all this onerous encryption on the cinema releases, high-quality pirated copies still very quickly make it out. So basically they have this very secure scheme for getting movies to theaters, but everything else is full of holes. Makes you wonder if all the effort and cost to secure the theater distribution chain is worth it. If yo…

>If you're going to allow playback on devices in "adversarial" hands (streaming, home physical media playback), it's going to be incredibly difficult to restrict copying. Kaleidescape movie players[1][2] are an example of an "adversarial" environment in customers' homes but so far, their DRM is still unbroken by pirates. (10+ years of Strato players deployed out in the wild but still not defeated yet.) The 4k 100+ GB…

If HDCP strippers work they should also work on Kaleidescape.

I wonder if they use watermarking so they can "burn" the player after a single rip.

Re: How encryption for Cinema Movies works

#100

Post by sethhochberg »

lb1lf wrote: post #62
johnisgood wrote: post #60

Earlier quoted context omitted.

I think the question remains, is it still worth it given these holes?

It presumably is, as the effort is kept up despite the cost and inconvenience. My guess would be that the plan is mostly to ensure that when a new release premieres in theatres, going to a theatre is the only way to experience it in high quality. It doesn't really matter all that much if the people who waits for it to arrive on Netflix gets a pirated copy; it does matter if the ones forking over $20 to see it in a th…

A really important element of this is that much of the burden of maintaining the DRM is on the theaters, and the theaters themselves are the ones who care about protecting the theatrical release period: you might be less likely to pay them for a ticket if you can get a high-quality copy at home before the actual streaming/media release

It’s a different dynamic than we typically talk about with DRM. Most of the time DRM is something imposed on a consumer who doesn’t really want it. But in this case, the consumer is the theater and they really do want the protection.

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