How to remove an audio track from an mp4 video file?

Question

I have an mp4 video file with multiple audio tracks. I would like to strip away the rest of the tracks and keep just one. How do I do this?

Answer 1

First run ffmpeg -i file.mp4 to see which streams exists in your file. You should see something like this:

Stream #0.0: Video: mpeg4, yuv420p, 720x304 [PAR 1:1 DAR 45:19], 23.98 tbr, 23.98 tbn, 23.98 tbc
Stream #0.1: Audio: ac3, 48000 Hz, 5.1, s16, 384 kb/s
Stream #0.2: Audio: ac3, 48000 Hz, 5.1, s16, 384 kb/s

Then run ffmpeg -i file.mp4 -map 0:0 -map 0:2 -acodec copy -vcodec copy new_file.mp4 to copy video stream and 2nd audio stream to new_file.mp4.

Answer 2

Related issue—removing all audio tracks from an mp4 file can be done thus:

ffmpeg -i input_file.mp4 -vcodec copy -an output_file.mp4

Answer 3

Identify stream numbers:

$ ffmpeg -i in.mp4
   ...
   Stream #0:0: Video: ...
   Stream #0:1: Audio: ...
   Stream #0:2: Audio: ...

Use -map _file_:_stream_ to select which streams to process and output

$ ffmpeg -i in.mp4 -map 0:0 -map 0:2 -vcodec copy -acodec copy out.mp4

see: https://ffmpeg.org/ffmpeg.html#Advanced-options

Answer 4

I used Avidemux (GUI) several times, and ffmpeg (console).

In Avidemux, you choose "Audio" -> "Select tracks" in the main menu; then save you video as a new file.

Interestingly enough, in some cases Avidemux produced "better" output than ffmpeg.

just in case, Avidemux and ffmpeg are in the standard Fedora Linux repository. (I'm sure they are standard in other Linux flavors, too.)

Answer 5

You could try avidemux which handles only one audio file internally (and therefore forces you to select one specific track). I've never tried it with .mp4 but it works with other formats.

Answer 6

-vn or -an will remove all the video or audio tracks. Supplying -vn -acodec copy will remove video; -an -vcodec copy will remove all audio.

-vcodec copy specifies that ffmpeg should do a straight copy the existing video track (and not do any processing/encoding of it). If you don't specify it, then it will still work but ffmpeg may re-encode the existing video track and the operation will use more CPU and may take considerably longer.

Answer 7

Using avidemux in command-line.

(In Avidemux GUI, as decribed in https://unix.stackexchange.com/a/85834/4319 above, you simply select/unselect the audio tracks, and save the file. (Everything is copied to the new AVI.))

I've looked at what kind of projects are saved as SpiderMonkey or TinyPy projetcs for my actions, and it turned out that the SpiderMonkey (JavaScript) project lacks the audio track selection actions which I needed, but the TinyPy (Python) project did have them.

I removed everything unrelated (a dozen of unneeded lines), and this is what I got in my some_series.py:

#PY  <- Needed to identify #
#--automatically built--

adm = Avidemux()

adm.audioClearTracks()
adm.audioAddTrack(1)

It leaves track 1, but drops track 0.

Then I ran a batch conversion of many files with a command like this one:

for f in *.avi; do avidemux3_cli --nogui --load "$f" --run ../some_series.py --save ../some_series/"${f%%.rus.eng.avi}".eng.avi --quit; done

It copies everything, but drops all but the needed audio track.

The way to run avidemux from command-line was learned by me from https://www.avidemux.org/admWiki/doku.php?id=tutorial:batch_processing, although they do not mention the Python scripts, only the JS ones (which didn't work for me).

Answer 8

An alternative, easy, way to do this with a GUI/app on macOS is Subler

It's also available on HomeBrew :

brew cask info subler
brew cask install subler

Answer 9

If you don't mind the program being GUI, with Blender's video editor you can do that and much much more.

Answer 10

The ffmpeg program has been replaced by avconv. avconv has very similar usage to ffmpeg, thus all the commands in this post can be something like:

avconv <old ffpmeg command line options>

Follow this link to install avconv if you're on Ubuntu.