What technology is it that prevents SVP from being used along with the internal Kodi player?

I'm running both Windows and Linux for Kodi, in Windows I use DSPlayer, i.e. DirectShow, and on Linux I can get SVP to work with mpv as external player.
I would love to run Kodi solely on Linux, but using mpv disables all OSD menus, so I can't download subtitles etc via the OSD = no go.
Windows however works, but its Windows so... eh..

Basically I'm just wondering whether the internal Kodi player will ever be compatible with SVP so that the whole setup of Kodi + SVP will become platform agnostic?