jimbo45 said:
Hi there @CountMike

If you have the DVD's already in .iso format try the makemkv program.
Then wondershare will convert mkv to mp4 in secs though I'd keep it as mkv.

BTW wondershare can also convert to H.265 HEVC format if you have a nice fast machine and cuts down storage space dramatically.

If DVD's were made from camcorders etc then you might have data format or m2ts format rather than normal DVD format.

Cheers
jimbo
No, I don't have them in ISO format only direct copies from DVD disks.