I would like to add multiple mp3 files to an mp4 file. For adding a single mp3 to an mp4, I used this command with success:

"-i /path/to/mp4File -i /path/to/soundmp3File -codec copy -shortest path/to/output/fileWithSound"

But I'm stuck with adding another mp3. I tried this, but it didn't work:

"-i /path/to/mp4File -i /path/to/soundmp3File1 -i path/to/soundmp3File2 -codec copy -shortest path/to/output/fileWithSounds"

How can I make it work with multiple audio files?

1 Answer 1



-i /path/to/mp4File
-i /path/to/soundmp3File1
-i path/to/soundmp3File2
-map 0 -map 1:a -map 2:a
-codec copy -shortest path/to/output/fileWithSounds

FFmpeg will automatically select one video and one audio stream from among all the inputs. -map options are required to include all streams.

  • For some reason only one audio stream ends up in my output file. Multiple streams only work if I amerge, but that's slow. I use the command you pasted. Unfortunately I accepted before trying.
    – WPMed
    Nov 19, 2018 at 11:37
  • Share full log.
    – Gyan
    Nov 19, 2018 at 11:54
  • I think I may have misunderstood multiple things about mp4. So if I add multiple audiotracks, will a player actually play all the tracks included? So I think the reason I only hear one audio in the output is that the player picks one. Does it make sense?
    – WPMed
    Nov 19, 2018 at 12:02
  • 1
    Yes, that's expected. You'll need amix filter if you want to hear all sounds at once - this will produce one track with all tracks mixed. A video player will only play one track at a time.
    – Gyan
    Nov 19, 2018 at 12:45

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