I Want to Burn 4K UHD BluRays on PC and Play Them on a 4K BluRay Player. Does it Work?

First of all, if you are using any copyrighted movies you won't get very far. Even if you circumvent the protection to be able to RIP the content you can't play most on modern BluRay players (2013+) as they'll implement Cinavia audio protection which keeps MUTING the audio.

(not sure how many movies do this, but probably most by now. if the movie has Cinavia it's POSSIBLE to watch on PC but not on a modern BluRay player)

Compressing the audio doesn't fix the issue either.

I'm not sure what else you could be referring to.

*Now, the COST of these discs is prohibitive anyway so you might as well just buy the movies.

Also, the diminishing BENEFIT of video means that you can easily compress high quality video anyway (I'll assume it's legally obtained) and easily fit it on a normal BluRay, dual-layer disc that may cost about $2 in bulk.

4K BluRay players support H265 (HEVC). I did a little experiment and took my Avatar BluRay (1080p, not 4K) and compressed it down to the point where I can start to tell in some scenes that it's not BluRay. I sat about 1.6x the diagonal of my high-res monitor.

(Yes, it was much more obvious sitting even closer but you wouldn't do that. just trying to find the low-point. I'd probably go 2x higher file size to be safe)

Size?

1GB for two hours. Yes.

So that's basically the low-end for "almost" BluRay quality. Now, 4K doesn't need 4x the size. Again, diminishing returns. It's hard to tell the difference. I'll give it at MOST about 2x (including HDR content).

So that puts the minimum for 4K (HEVC) quality content at about 1GB per hour, or 2GB for a 2-hour movie. (UPDATE: add DTS-HD or whatever audio you want on top of that but it's not going to change the type of DISC you burn to. Adds 1GB or so for highest?)

You have something like 44GB on a $2, normal BluRay disc. There's absolutely no need to get 100GB discs unless you want a straight copy (if you even can) without compressing.

*I really wonder who will bother making 100GB discs for content though for 4K machines. Again, they support HEVC/H.265 so it makes much more sense to simply compress the data with that encoder.

(FYI, when I compressed my BluRay collection the most I ever needed with H.264, not H.265 which is about half, was 4GB per hour. Sitting 1:1 to my high-res monitor I can't tell the difference between original movies and 8GB movies that I compressed myself. Or 4GB for a two-hour movie using HEVC though I don't do that since it doesn't work on my other devices)



UPDATE:
I revisited my HEVC compression (based on 10 minutes). I calculated the total size it would be which is about 1.4GB for a 2h40minute movie.

Remember, that's "almost" BluRay quality as I discussed above. Now, let's round that to 2GB and then 2x more for 4K HDR. That's plenty if compressed properly to get to the maximum (arguably) that a human can see sitting close to a good 4K HDTV. L

Add another 2GB more for super good audio (I compressed it though it sounded great to me) and we're looking at roughly 6GB needed for a 2h40min, HEVC, 4K movie.

Even if you argue that's not enough due to certain types of compression errors we're still talking about 6GB size so even 25GB (22.3GB or so usable) is plenty for a movie.