I’m talking about the Blu-ray structure. But I know having official support for complete Blu-ray .iso images would raise hell for licencing issues.
So instead I propose to provide a naive support for the simple relation between index.bdmv -> playlist/.mpls ->stream/.m2ts. E.g: look how Media player classic(MPC-HC) did it. There are a few players that have this, and most of them just load automatically the longest duration playlist.
The structure of the index.bdmv and .mpls files are very intuitive, just open it in a text editor. Or google “.bdmv .mpls format”.
And to prevent legal issues, dont advertise it as Blu-ray support(well technically it isnt). Just add the file extentions to the list of files supported by the player. (.bdmv .mpls). You already support .m2ts files, so this would be just tiny step further and provide a great value to your customers.