instantreplay.bat

set FFMPEG_EXE="C:\Program Files (x86)\Screen Capturer Recorder\configuration_setup_utility\vendor\ffmpeg\bin\ffmpeg.exe"
set OUTPUT_INTERVAL_IN_SECONDS=60
set OUTPUT_DIR_WITHOUT_TRAILING_SLASH=%userprofile%\documents\instantreplay
set OUTPUT_FILES_TO_KEEP=120

:loop
for /f "tokens=2 delims==" %%I in ('wmic os get localdatetime /format:list') do set timestamp=%%I
set datetimestart=%timestamp:~0,8%-%timestamp:~8,4%_%timestamp:~12,2%

%FFMPEG_EXE% -loglevel info -t %OUTPUT_INTERVAL_IN_SECONDS% -f dshow -video_device_number 0 -i video="screen-capture-recorder" -vcodec libx264 -pix_fmt yuv420p -s hd720 -preset ultrafast -vsync vfr -acodec libmp3lame -f mpegts - | %FFMPEG_EXE% -f mpegts -i - -c copy "%OUTPUT_DIR_WITHOUT_TRAILING_SLASH%\%datetimestart%.mkv"

for /f "tokens=2 delims==" %%I in ('wmic os get localdatetime /format:list') do set timestamp=%%I
set datetimeend=%timestamp:~0,8%-%timestamp:~8,4%_%timestamp:~12,2%

move /Y "%OUTPUT_DIR_WITHOUT_TRAILING_SLASH%\%datetimestart%.mkv" "%OUTPUT_DIR_WITHOUT_TRAILING_SLASH%\%datetimestart% to %datetimeend%.mkv"

for /f "skip=%OUTPUT_FILES_TO_KEEP% eol=: delims=" %%F in ('dir /b /o-d /a-d %OUTPUT_DIR_WITHOUT_TRAILING_SLASH%\*.mkv') do @del "%OUTPUT_DIR_WITHOUT_TRAILING_SLASH%\%%F"
goto loop

:dev notes
https://superuser.com/questions/108034/rolling-desktop-recorder
http://www.linuxquestions.org/questions/linux-newbie-8/how-to-use-ffmpeg-x11-grab-inside-windows-917907/
http://www.ignas.in/blog/130625_realiable_way_to_get_date_in_batch_scripting
mkv is used so that video can be watched while it's being recorded
https://www.howtogeek.com/tips/how-to-run-a-scheduled-task-without-a-command-window-appearing/