How encryption for Cinema Movies works

I'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

I think JPEG 2000 is simply the chosen format for distribution of the video, not for security.

JPEG 2000 has some interesting properties for very high quality video storage and transport where bandwidth is not a concern. The traditional encoded video formats we know are less preferred at this scale.

JPEG 2000 is resource intensive, though. The decoding hardware is probably either GPU based or using an FPGA implantation from one of the providers who makes hardware for this.

It's definitely dedicated hardware JPEG2000 decoding.

DCPs were designed to be jpeg200 streams with a bunch of audio streams as well.

The idea was that they wanted up to 16bit colour (per channel) lossless imagery. The encryption was (or so I recall) was an extra feature.

One movie can be 200G to 1TB large. The chunked encryption allows it to seek the movie without decrypting from the beginning.

But any computer with full disk encryption also has seekable encryption

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.