I recently found myself with a number of smaller MP4 video files that I really wanted to stitch together into a single, longer video. My first thought was to download one of the many highly capable video editors from the Ubuntu repositories. It turns out there is an even easier way:
First, you’ll need to make sure you have the gpac library installed:
sudo apt-get install gpac
Then you’re going to use the MP4Box utility that comes with gpac like so:(note the large number of uppercase letters):
MP4Box -cat video1.mp4 -cat video2.mp4 -cat video3.mp4 (...) -new newvideo.mp4
Just throw in another “-cat “filename.mp4” for each file you want to stitch, and the file specified after the “-new” will be your new video.
Easy as can be!