1by1 as a mplayer launcher?

[petrus]

The idea is to make the "external programs" feature for certain file formats automatic.
So when it finds one of those, "mplayer.exe %1 -loop 1" is run.

Your task, if you accept the mission, would be to figure the "one by one" part.
Make the program wait for mplayer.exe to close before moving on to the next file, and prevent that every single of those files is run at once.