sound fonts in .dll

[Ian Graham]

Hallo, everyone
(I may have to post this in several bites, to get at least something through the Spam Filter)
I appreciate I'm coming very late to the sound-fonts 'game'. My question is probably very basic to most people here......I have several fonts in *.dll format, including several specialist ones which are really very good. I would like to understand a little about this as a format.
Is it the original sound-font format?
How can it be described, technically, as distinct from sf2, sf3 and sfz (etc) ? And most specifically, does anyone know of a software that will load both pre-existing Midi files as 'script', and a *.dll as output. (I have applications which will take a live midi feed, but that's not quite the same thing.)
Many thanks

Ian G
Wales UK

[mcbpete]

That sounds like the sound fonts have been embedded/compiled into a bespoke soundfont player: Sound fonts are normally in the .sf2,.sf3 & .sfz fileformat and you use something like Bassmidi to use them in your DAW

Are you sure they're definitely soundfonts and not just sample-based VSTs ?