This option allows segment filenames to be specified. Unless -hls_flags
single_file is set the filename is used as a string format with the
segment number.

Example:
ffmpeg -f lavfi -i testsrc -c:v h264 -map 0 -hls_segment_filename
bar%03d.ts foo.m3u8
Signed-off-by: Christian Suloway <csuloway@globaleagleent.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>