Difference between MX4SIO, MC2SIO and SIO2SD and ESR question

[Windows_10_User]

What's the difference between MX4SIO, MC2SIO and SIO2SD and can ESR play PS1 and PS2 CD discs?

EDIT: So, it seems SIO2SD was the original name of MX4SIO but it was changed to the latter because there was already another project with the same name for another console and MC2SIO is a clone of MX4SIO.

EDIT 2: It seems ESR can only play physical PS2 DVD games and PS2 CD's have to be converted to DVD.