Mixing metadata

[CaveDoctor]

Is there a way to separate 4K metadata from a file and add it to a 1080p file to place it in the 10 bit color space?

[deleted user]

I don't know if there is any way to losslessly add the metadata to an existing stream without reencoding it. But I can tell you that 10-bit has nothing to do with the metadata, the metadata exists to my knowledge for mapping HDR values onto displays with lower dynamic range than the full HDR spectrum. 10 bit is not even HDR per se, it's just the bit depth - you can do a 10 bit encode in SDR, no problem.

With that said, yeah, I think you need the metadata for players to play a video as HDR. But for one, I don't think it works with x264, at least not so far. And for another, I am not aware of any tool that can add them to an existing h265/x265 stream, though I think it should be theoretically possible.

[CaveDoctor]

Say for example I had a blu ray set of a show and I wanted to test out doing this with 1 episode.
My goal for said show is to reencode it in x265, sourced from a blu ray.
Now, say that I have a heavily compressed stream from a streaming site, but it's in 4k with 10 bit HDR, or Dolby Vision.
My end goal is to create a 2k version of this film or show.
What would I need to do?

[deleted user]

You can of course use x265 to do a normal SDR encode from a Blu Ray, in fact many people are already doing this. Obviously it won't be HDR. Unless you yourself do some HDR color grading, but what's the point?

You would downscale it and make an encode of it in 2K, and add HDR metadata during the encode to make it work as HDR, presuming that's what you want. Though I don't know how the compatibility would be for a 1080p HDR stream with general consumer hardware, but I think it should work in principle.

[CaveDoctor]

I think 1080p or 2k is superior for a number of reasons, as standard 4K content on Blu-ray makes 4:4:4 images when downscaled right.
I read that 10 bit is easier to store than 8 bit and has less banding.

So, my goal, x265 compression, 10 bit color, 1080p or 2k content at 4:4:4.
The other goal, Anamorphic storage, 4:3 2k might be a good place to start, 1536x2048.
I also want to be able to store the image in an MKV container, and eventually use MKV menus when they become a thing.

So I can either upconvert an image to 10 bit from it’s standard 8bit using a program, or I can mix images from 2 different sources to enhance the color.

[CaveDoctor]

You can of course use x265 to do a normal SDR encode from a Blu Ray, in fact many people are already doing this. Obviously it won't be HDR. Unless you yourself do some HDR color grading, but what's the point?

You would downscale it and make an encode of it in 2K, and add HDR metadata during the encode to make it work as HDR, presuming that's what you want. Though I don't know how the compatibility would be for a 1080p HDR stream with general consumer hardware, but I think it should work in principle.

From what I gather, it's probably about stacking captures.
Hypothetically speaking, If I wanted to take a Rip of Wrath of Khan from iTunes, with it's HDR color space, and downscale it to 2k, and combine it with the bluray of Wrath of Khan, that is from the same remaster, and upscale it to 2k, would I reap the benefits of having the 10 bit color data, on that new file I create?