[HELP] Setting PAR and color matrix on container-level

[Selur]

I have a workflow where I take SD videos, for example PAL 16:15, bt470bg/bt470bg/bt709, and I deinterlace + bob using Hybrid. However, the output file, no matter what container or encoder, will not contain the PAR or color matrix/curve hints

PAR and VUI signaling should be on stream not container level.
MKV allows additional HDR related signaling through the container.

I could probably add support through ffmpeg, mp4box, mkc for additionally signaling vui stuff through the container.
(ffmpeg is well documented over at https://www.ffmpeg.org/ffmpeg-all.html, mkv is well documented through https://mkvtoolnix.download/doc/mkvmerge.html)
Main problem is I would need some documentation, for mp4box, since

colr (string)

set color profile for imported video content (see ISO/IEC 23001-8). Value is formatted as:
* nclc,p,t,m: with p colour primary, t transfer characteristics and m matrix coef
* nclx,p,t,m,r: same as nclx with r full range flag
* prof,path: with path indicating the file containing the ICC color profile
* rICC,path: with path indicating the file containing the restricted ICC color profile

see: https://www.mankier.com/1/mp4box#Hinting_Options
-> without any clue how ISO/IEC 23001-8 I would need some additional details on how to use nclx and nclc

Cu Selur

Ps.: busy this weekend (helping a friend move to a new apartment, but I could look into it next week)