Some years later, back again and wanting to convert these to get them into a better format. They were on DVD, I used an older version of imgburn probably around 2009 to 2011 to rip from DVD to PC and at that time the program seems to have generated BIN/MDS. Based on the notes above is the route to use imgburn to convert to ISO, mount them then use a program to convert to MP4 - does imgburn do this?
I'm on Windows 10.