Genki
as you said - back to the roots then
MPC literally only shows the 'playbar' or what ever that's called; and nothing else as if it was a music player only
I believe this means video decoder was unable to decode video stream.
- Check "File" -> "Properties" windows in MPC-HC. There should be Video stream on "Details" tab and correct information on MediaInfo tab.
- Check if MPC-HC's internal LAV filters is in use.
- Update MPC-HC to the latest version.
BUT keep in mind that source video (before compression) is always 8-bit, and you're playing it on LCD panel with probably 6-bit precision. There's always a "color compression" from 10-bit to 8 or 6-bit somewhere - may be in video decoder, may be in video renderer, may be in the video card plus additional compression in LCD panel.
So trying hard "to view 10-bit as 10-bit" is just pointless. There's actually NO 10-bit
And making setup with "hi10p decoder" + "SVP or any other postprocessing working in 8-bit" + "hi10p output in madVR" is even stupider.