Gluing 2x mp4 clips CLI

Question

Video

Hello.
For a week I have been dealing with the problem of merging 2 mp4 clips into one.
On freelance from Habr, no one can really help.

Maybe one of you has done something similar?

MP4Box glues it is not clear how the video is not working.
mkvtoolnix constantly writes that a video decoder is not specified in one of the videos. (there is almost no difference in the videos)

The task is difficult because it would not translate both files into the 3rd intermediate format.

I will be glad if someone can help.

Answer 1

and if you just cat-th blind them?
or ffmpeg...

Answer 2

ffmpeg -i test1.mp4 -i test2.mp4 -vcodec copy -acodec copy test12.mp4 -newvideo -newaudio
More or less like this

Answer 3

VirtualDUB or Sony Vegas (the second option is more complicated due to the high cost of the license).