Check Pattern:

  Here you can tell APlayer how it should recognize archives. Archives will
  only  be  recognized by their filename, so you can type a filepattern for
  every archiver here.

  For instance the default lha checkpattern is (#?.lha|#?.lzh) which  means
  that every file ending with either ".lha" or ".lzh" will be recognized as
  a lha archive.