Continuing the discussion from Join Files not working on MP4 videos:
In 2017 we had to live with the above mentioned hack when we wanted to join a few media files 
... Luckily, things look brighter these days 
All it takes is a one-liner:
@nodeselect
@firstfileonly
ffmpeg.exe -f concat -safe 0 -i {allfilepath|regex=(.*)|to=file '\1'|filem|utf8|nobom} -codec copy {filepath|..}{date|yyyyMMdd}-{time|HHmmss}{file|ext}
pause
The nifty part is the allfilepath code that generates the temp file for FFmpeg. It will also take care of this issue.
@firstfileonly is needed because we use the original file's extension for the output file and don't want to create multiple joined files.