UHD Blu-Ray Video Compression

[Razor54672]

Does a UHD Blu-Ray use lossless HEVC to compress Master movie files? Or is it lossy?
If so, does that mean encodes essentially take a lossy file as input to create another lossy file? 
Wouldn't that result in perceptible quality loss?

[Bombastinator]

1 hour ago, Razor54672 said:

Does a UHD Blu-Ray use lossless HEVC to compress Master movie files? Or is it lossy?
If so, does that mean encodes essentially take a lossy file as input to create another lossy file? 
Wouldn't that result in perceptible quality loss?

This is the kind of thing wikipedia is really useful for.  Whatever they have is going to likely be their own thing though.  Whatever it is it’s going to be proprietary. It may be a version of HEVC, but if it is there will likely be significant differences literally to keep it from being compatible  One of the things about blu-ray is it’s so heavily concerned with drm and copy protection that it almost couldn’t be put on windows, and windows had to be modified just to allow it in some fairly painful ways, which were so onerous that it almost didn’t happen. The concept of the system using something FOSS just seems unlikely to me.

[tikker]

1 hour ago, Razor54672 said:

Does a UHD Blu-Ray use lossless HEVC to compress Master movie files? Or is it lossy?

To my knowledge it's a lossy compression. Raw uncompressed footage would be hundreds of gigabytes if not terabytes:

(3840 x 2160) pixels/frame * 24 frame/second * 10 bit/pixel = 248 MB/s

 

That translates to ~15 GB per minute, or 1.8 TB for a 2 hour uncompressed movie.

1 hour ago, Razor54672 said:

If so, does that mean encodes essentially take a lossy file as input to create another lossy file?

If you re-encode it, then yes. You lossy compress something already compressed and hence you will likely degrade quality to some extent. If you do a one-to-one rip of the disc, then there is no re-encoding and hence there should be no difference between the two.

1 hour ago, Razor54672 said:

Wouldn't that result in perceptible quality loss?

If you don't choose your settings carefully it will be noticeable yes.

[TheGreatestGazoo]

Yes, UHD Blu-Ray supports the very efficient HEVC for encoding. Also 8K UHD is supported in HEVC.

[Bombastinator]

7 hours ago, TheGreatestGazoo said:

Yes, UHD Blu-Ray supports the very efficient HEVC for encoding. Also 8K UHD is supported in HEVC.

Wow, that avatar is a seriously deep cut.