Extract Audio from an MP4

[Antebios]

I'm not sure if this is the right forum, but how do you go about extracting the audio from an MP4?

[Joaquins Void]

VLC can do it, but I can't remeber how right now.

[nofish]

http://www.pazera-software.com/produ...dio-extractor/

[DVDdoug]

Have you already tried opening the file in REAPER? That might "just work".

Audacity can usually do it (with the optional FFMPEG import/export library).

TAudioConverter can usually do it.

SUPER can do it (with or without converting the audio to a different format).

[Nystagmus]

I had trouble opening MP4's in Reaper.

But Foobar2000, which is freeware can do the conversion.
http://foobar2000.org

Load up your MP4's or M4A's or AAC's or WebM's or MKV's or OGG's or MP3's or whatnot and convert them to whichever other format. It's really pretty powerful. You can edit the meta data before and after too.

Be sure to edit/save the conversion settings before you commit to them.

[Antebios]

Originally Posted by nofish

http://www.pazera-software.com/produ...dio-extractor/

The one you pointed me to worked great. Thanks.

[airon]

You can probably just convert the MP4 to any audio format with Reapers batch converter. Find it in the file menu. You may need to have VLC installed as well. X64 Reaper -> X64 VLC.

[Judders]

I use Blender for that. It actually has a pretty decent video editor in it these days.

Never had any luck with VLC conversions, something always wrong with the wrapper.

[toddhisattva]

FFmpeg will do that and much, much more.

ffmpeg -i input.mp4 -vn -c:a copy output.m4a

Will copy out the AAC to m4a no transcoding or quality loss.

ZeraNoe has the Windows builds I use.
Mac builds that I haven't used.

[airon]

Originally Posted by toddhisattva

FFmpeg will do that and much, much more.

ffmpeg -i input.mp4 -vn -c:a copy output.m4a

Will copy out the AAC to m4a no transcoding or quality loss.

ZeraNoe has the Windows builds I use.
Mac builds that I haven't used.

Nice tip for quick stream extraction. Thanks.

[martifingers]

I seem to remember that Adobe Audition reads the audio directly from an mp4 file. I will try it if I get a chance or could someone confirm/refute this?

[hlavsa]

Separation of audio from video track is easy: Item - right click - Item Processing - Explode multichannel audio to...
That will create separate audio subtracks (WAV) which you can easily drag anywhere in you project.
Also very handy is muting audio in original track: Item - right click - Source properties (Ctrl-F2) - check "Ignore audio".

[mikefloutier]

Many thanks for this, it worked fine for me the other day BUT this morning I got this error, any ideas? -

Multi-channel explode - "Error creating new single-channel media items"

[mikefloutier]

Originally Posted by mikefloutier

Many thanks for this, it worked fine for me the other day BUT this morning I got this error, any ideas? -

Multi-channel explode - "Error creating new single-channel media items"

Any ideas? I'm left this project on the back burner for a few days in the hope of inspiration (or hopefully you guys - no pressure ) but I revisited this morning.

I do need to do this as it's fundamental to the project - seems such a simple thing; what am I missing?

It's a standard mp4 file with video at 1280x720 30fps with Audio: 48kHz stereo 192kbps.

I obtained the file by recording it from a larger file in VLC media player.

Any ideas?

[nepenthe]

Originally Posted by mikefloutier

Any ideas? I'm left this project on the back burner for a few days in the hope of inspiration (or hopefully you guys - no pressure ) but I revisited this morning.

I do need to do this as it's fundamental to the project - seems such a simple thing; what am I missing?

It's a standard mp4 file with video at 1280x720 30fps with Audio: 48kHz stereo 192kbps.

I obtained the file by recording it from a larger file in VLC media player.

Any ideas?

This sounds like a problem to me. I use Reaper to extract audio from MP4 every day on OS X and it works without me having to do anything. I also just set up a friend on Windows with Reaper and audio extraction was working fine. Maybe double-check that LAME is up to date and properly installed? Or select the audio and render it as a WAV?

[mikefloutier]

Thanks nepenthe, it worked ok next time (after I’d found a workaround ) some glitch.

[fakemaxwell]

You don't even need to explode it, just glue the item and you'll be left with only the audio.

[enjolis]

Originally Posted by fakemaxwell

You don't even need to explode it, just glue the item and you'll be left with only the audio.

This glue idea works great. You can even glue just one lone item to itself. The only downside is that it creates more files. I don't know why the explode multichannel audio is greyed out.

[panicaftermath]

I've never been able to open m4a files in Reaper, and end up using Audacity to convert them to wav or flac.

But mp4 files open without problem and the audio can then be extracted.