I have a very old Sony Blu-ray player from about 10 years ago, and NJVC’s ISOs work fine on there when burned to disc. But I have a similar issue to you when trying to watch them on my PC with VLC. After “mounting” the ISOs as virtual discs in Windows 10, I can access the menus and extras etc. but the main films don’t play. In my case, the timer moves at about 10x speed when trying to play the film, but there is no video/audio. Has anyone got the ISOs to work in VLC?
Harmy’s mkv files work fine in VLC, however.