In article , says...

My files are from Windows Media Center Recorded TV and can be 8+
GigaBytes Long.

No concatenations is desired.

I do that also using a TV USB Tuner. Makes perfect copy of on-air
(attenna) including sub-titles. I then convert them to a size more
manageable, e.g. XVID/MP3 if I want to keep it. Trouble is there's ads
interspersed within the video so truth be told I almost always also
download a torrent without ads to keep if I want to retain a copy.