How to merge .webm with .mp4 in linux with one command?

Question

Video

there is a video without sound and a separate audio track for it,
you need to combine them
Preferably with one command

Answer 1

ffmpeg will help. Something like:
-i audio.mp3specifies one of the inputs, a file with sound;
-i video.webmanother input, video file;
ffmpeg itself will figure out where to get the sound from, and where the video track comes from, if each one has one and you don’t have to choose.
-c:v libx264specifies the video codec to use to repress the video track;
-c:a aacaudio codec to repress audio.
result.mp4where to save the result.