Merging a video and audio with ffmpeg or other. Possible ?

[DB83]

Ok. I have never got on with cmd line progs and use gui's for such tasks.

The issue at present is yt-dlp and the gui's that use it particularily with yt '18+ sign in to prove your age' restricted vids. None of the latest versions appear to work and all give a variety of errors - the latest, I guess, will not even work with Win7 and gives a msg that says that an Windoze item is missing.


But one of the gui's does 'work' after a fashion. That is to say that it downloads the video and the audio but in two separate .mp4 files. I have already 'Googled' this and posts suggest that VLC can do a merge yet having followed the instructions or online apps these do not work either.


So I ask my friends here if ffmpeg or something else will work and if so how do do it. Sure. I despise cmd line solutions but if it is 'easy', I am prepared to give it a go. And I am am sure that ffmpeg is used with the gui's except that the one that 'worked' borked out before that final process.

[poisondeathray]

For ffmpeg commandline if each have only 1 track of video, audio each - it would be

ffmpeg -i video.mp4 -i audio.mp4 -c:v copy -c:a copy output.mp4

or you could use some GUI's mkvtoolnix for MKV,

or any number of mp4 muxing GUI's such as mp4tool or mp4muxtool for mp4
https://www.videohelp.com/software/My-MP4Box-GUI
https://www.videohelp.com/software/MP4-tool
https://github.com/jessielw/MP4-Mux-Tool

[ProWo]

Use clever Ffmpeg-GUI.
Load the video mp4, click main page, click multiplex.
Drop the audio mp4 into the grid, select both streams on the left and click multiplex.
Done.

[DB83]

Thank you both.

The clever GUI worked a treat. I did try some of the otehr suggestions but these did not.

[cholla]

I use Clever some of the time & it works fairly well.
This is a simpler ffmpeg code (by only a little) than poisondeathray's.

ffmpeg -i video.mp4 -i audio.mp4 -c copy output.mp4