[FEATURE]: Aliases for ffmpeg tone curves and primaries

Ffmpeg provides a large set of primaries and transfer functions (OETFs) for use as metadata in video formats, with the -color_trc and -color_primaries parameters (or equivalent AVFrame members).

Allowed values for these options are stated to come out of ISO/IEC 23001-8:2013 in libavutil/pixfmt.h, and reference existing standards and recommendations that are for the most part already implemented in colour-science.

Is there any interest in adding aliases to let people reference these more easily?

[ValZapod]

And the luma vs luminance changes

Well, technically we do support linear transfer (so Y of YCbCr is indeed Y of XYZ) just not in ffplay directly (strange open bug), alas, but mpv that uses ffmpeg almost in full, does support it using ffmpeg primitives.

Check with mpv vs ffplay: https://forum.videohelp.com/attachments/43324-1507526652/dpx-sequence.zip

We do (at least with zscale) support constant luminance, where Y of YCbCr is indeed Y of XYZ since you first apply the matrix on to get linear Y of YCbCr and only then apply nonlinearity to get Y’.

[KelSolaar]

If they are all the same we could alias them as an option, we sometimes do that, e.g. https://github.com/colour-science/colour/blob/develop/colour/characterisation/datasets/colour_checkers/sds.py#L3188, then we would describe that they are all the same in the doctrings. colour.models.rgb.video works for me!