Box currently doesn't support proper dolby vision and audio formats without playing through kodi.
Mxplayer it's the problem itselfs. The passthrough don't work for years.
Vlc player on Z12 and Novaplayer works, but if you speed forward the movie, it's glitchy yes and will hang with a terrible hard scratching sound, and color become strange and go back to desktop or reboot after 20 seconds.
So i use kodi so long, till update of vlc player or nova player or Z12 firmware.