> 31. May 2024
I’m trying to understand the timeline here; the article was originally written last year and the latest spec is also from 2024 but the article has a link to this HN thread created yesterday?
How encryption for Cinema Movies works
111–120 of 124 posts
Re: How encryption for Cinema Movies works
#112Earlier quoted context omitted.
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.
Although you still have four frames of latency if you do it that way. All the audio has to be delayed to match. Parallelized decode of JPEG 2000 frames is quite possible, though. The choice of JPEG 2000 is unexpected. Most of the neat features of JPEG 2000 are useless for cinema. Being able to construct a low-rez version from a truncated file isn't useful. Nor is the ability to divide the image into tiles and decompr…
> The choice of JPEG 2000 is unexpected.
What format would you have expected?
> Maybe the advantage is that you can have more than 8 bits of color depth.
Yes, that and the (at the time) near state of the art compression efficiency. I remember reading a technical document where the engineers designing the standard argued for 12 bits per component based on experiments and studies they conducted.
Re: How encryption for Cinema Movies works
#113Earlier quoted context omitted.
Where do you live? Where I live only professionals and nerds use movie playback that allows single frame stepping, it's definitely a fringe phenomenon here.
I live in the EU, but any good free movie player should allow stepping through video frames back and forth and also playing with any desired speed in frames per second. This is not a feature that requires professional tools. And I do not think that you have to be a pro or a nerd in order to want to see clearly many of the details of the kind "blink and you miss it".
That the tooling might be pervasive doesn't mean it gets any use outside of fringe groups.
Re: How encryption for Cinema Movies works
#114Even 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.
Quite often it's industry insiders themselves who release rips from the Blu-Ray screener disks sent for Academy Awards consideration.
Re: How encryption for Cinema Movies works
#115Earlier quoted context omitted.
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 D…
While at the same time dealing with potentially untrustworthy employees and the prisoner's dilemma.
Re: How encryption for Cinema Movies works
#116Earlier quoted context omitted.
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.
Although you still have four frames of latency if you do it that way. All the audio has to be delayed to match. Parallelized decode of JPEG 2000 frames is quite possible, though. The choice of JPEG 2000 is unexpected. Most of the neat features of JPEG 2000 are useless for cinema. Being able to construct a low-rez version from a truncated file isn't useful. Nor is the ability to divide the image into tiles and decompr…
The ability to read a lower rez version of the images is a feature that is actively used. That way you don’t need to have both a 2K and 4K DCP for movies that have a 4K version, 2K projectors can simply decode the 4K DCP at 2K resolution.
Re: How encryption for Cinema Movies works
#117Earlier quoted context omitted.
> 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 so…
> "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"
I remember an history professor saying that for a subject he was working on he had to borrow a book from the library of Congress (through the library of his university), where the only publicly available copy in the US was. Of course it was an academic book, so it's not exactly a common situation.
Re: How encryption for Cinema Movies works
#118> 31. May 2024 I’m trying to understand the timeline here; the article was originally written last year and the latest spec is also from 2024 but the article has a link to this HN thread created yesterday?
Maybe the author saw a bunch of hits coming from HN and edited his post to add the link to the discussion? It doesn't seem as if the author themselves posted their article.
Re: How encryption for Cinema Movies works
#119Earlier quoted context omitted.
Read their comments, the analog loophole is mentioned in the first one.
To be charitable to gp, they may be talking about "digital" instead of "analog" capture. E.g. something like HDMI capture hacks: https://www.google.com/search?q=hdmi+capture+hdcp+bypass The issue is the so-called "DRM" isn't just the encryption of the harddrive files. The DRM protection also includes the watermarks in the video images that survive the HDMI capture . If pirates don't want their $2000 Kaleidescape play…
I was talking digital. The output has to hit a device that does something with pixels at some point. At that stage it isn’t encrypted. (Think ribbon cable to LCD, or equivalent). No reason why an FPGA or some custom hardware can’t grab that, just requires engineering effort.
Re: How encryption for Cinema Movies works
#120I'm confused why it's encrypted as a JPEG image per frame instead of one AES encrypted video file. Since the same AES key is used for each frame it wouldn't add any additional security imo
As per asdcplib's author themselves in another clmment:
> Frame-by-frame encipherment, rather than whole stream, better supports random access and the famous tobacco intermissions popular in the EU.