If you put your mousecursor somewhere over "Capture file name format", a help-screen appears saying exactly what you wish to know, i.e.:
Code:
Format for file name:
%F - File name (mymovie)
%E - File extension (.avi)
%T - Movie Time (hh-mm-ss)
%FR - Movie Time in frames
%TS - System time
%DD - Date day
%DM - Date month
%DY - Date year
%A0 - Auto number, with no leading zeros
%A1 - Auto number, with 1 leading zero (01,02,03...)
%A2 - Auto number, with 2 leading zeros (001,002,003...)
%A3
%A4
the default format is bscap%A3
which produces filenames bscap001 .. bscap002 .. bscap003 .. etc .. bscap500.