How can I merge the sound of one video into another?

[kenny1999]

Now I've got two same but very old videos,
one is of much higher resolution, but it comes without sound. Sound is lost at all.
Another one is of much lower resolution, it is with sound.
This is a vintage video taken by me and for decades, I forget how they ended up like this.

How can I merge the sound from one video to another?

Thanks!

[jagabo]

You can try a simple remux with tools like mkvtoolnix or Clever ffmpeg GUI. But the audio may need to be adjusted to match the video first.