MP4Tools comes with two programs, MP4Joiner and MP4Splitter, to split and join MP4 files.

MP4Joiner allows you to join multiple MP4 files into one without reencoding and without quality loss.

MP4Splitter allows you to split an MP4 file into multiple files without reencoding and without quality loss.

As the description states, it comes with the two applications you can launch individually or one at a time. While they are different in size, they are similar in appearance. If you can use one, you can use the other.

Both have a options icon that looks like a wrench that gives you access to a few things, but primarily to force reencoding and a few settings to go with it.

With MP4 Splitter, just add the video you want to split, use the slider to add your split points, then select start splitting.

Now, to join the videos you just split back into one video, open MP4 Joiner, add the videos you want to join and press the join button.

MP4Tools isn't a full blown professional package. It's a lean, mean splitting and joining machine. You need few options as it saves the quality and you need no experience to cut and rejoin a video in munites.