CommaExts := CommaExts + ',';
    S := 1;
    I := 1;
    while I <= Length(CommaExts) do
    begin
      if CommaExts[I] = ',' then 
      begin
        WMPRegMultimediaExts(Copy(CommaExts, S, I - S), PerceivedType, MIMEType, ExtDesc);
        S := I + 1;
      end;
      I := I + 1;
    end;