Copying over HDR data to non HDR HEVC stream

[tijgert]

I'm trying to copy the HDR portion of a Remuxed movie to a compressed version of the exact same movie(source) without HDR.
Basically add HDR to the smaller non-HDR movie version so I don't have to recompress the HDR movie version myself in order to keep HDR.
I don't have Dolby Vision equipment so I am satisfied with regular HDR10(+).

Mediainfo shows the Remux video stream info as:
Dolby Vision, Version 1.0, dvhe.08.06, BL+RPU, HDR10 compatible / SMPTE ST 2086, HDR10 compatible

Using HDR10Plus-Parser-Tool.v1.34 I cannot find an HDR10 stream to extract, but I did find a DV RPU which I extracted.
(I am new in this, so please correct me if I use terms wrong or even make mistakes that you'd find basic).

I extracted the small version HEVC video stream and injected the RPU.bin with dovitool.
I then used MKVToolnix to replace the video stream in the small video version of the movie with the injected stream.
When I use Mediainfo to check it shows:
Dolby Vision, Version 1.0, dvhe.08.06, BL+RPU, HDR10 compatible
Before it showed nothing for HDR format, so it's a win, but not a total victory.
It lacks the SMPTE ST 2086, HDR10 compatible portion of it.

Is this result correct? Is there a way to improve my results to include the SMPTE ST 2086, HDR10 compatible portion?
Am I missing out on anything by not having that SMPTE ST 2086, HDR10 compatible portion?
Would recompressing the HDR source result in keeping the SMPTE ST 2086, HDR10 compatible portion or would that get filtered out anyway?

[lvqcl]

As far as I understand, an HDR video is not SDR video + some correction layer ("HDR portion"). The video stream itself is a part of HDR data.

[rwill]

HDR10 requires the pixel portion of a video stream to use the PQ transfer function and BT.2020 color encoding.

You need to decode the Dolby Vision stream to HDR10 if you want that.

As it looks like the DV stream is Profile 8.1 the pixel portion of the stream is already HDR10 backwards compatible - so just re-encode that.

You need to add the mastering display and light level information SEI to the stream so its HDR10, mediainfo should show these for your DV stream.

Its kinda sad, DV RPUs are stream specific and shouldnt be swapped around streams. I have seen this alot around here but it is just wrong.

[ErazorTT]

You apparently have some misunderstandings about that whole HDR thing. And since I thing the whole is in fact not very widely known, I'd like to try to shine some light on it.

First of all @lvqcl is right, you cannot separate the HDR part from the SDR part, as the video stream itself is the HDR part, nothing you could extract and add to an SDR stream.

Secoundly @rwill is right, in that the HDR part has a different transfer function and different color primaries then an SDR stream.

Thirdly, you are also partly right in the sense that there are indeed some HDR streams which do have additional information which can be extracted and moved and added to other streams! But here we are talking only about the Dolby Vision part of HDR streams, while the HDR part is entierly indivisiable as stated above.
The video you have there at hand is apparently a Dolby Vision video. Dolby Vision videos consist of a base HDR layer (called base layer), and the RPU information for dynamic tone mapping. Dolby Vision BluRays also have an additional enhancement layer which can either include actualy pixel information which are supposed to be added to the base HDR layer (called full enhancement layer) or without any pixel information (called minimal enhancement layer), in which case this layer is just holding the RPU information I mentioned before.

So the RPU you extracted includes just the dolby vision tonemapping information which is applied to the base HDR layer by your TV set (if you had a Dolby Vision compatible TV set, that is).

[kolak]

In shortcut- you can't do it.