separating audio from an mp4 file

I am running Windows 7 Professional 64-bit and wish to use Audacity to create mp3 files clipped from an mp4 video recording. The video is on my Android tablet.
How do I:

  1. Get the large video file to my Windows desktop to process it with Audacity.
  2. Make an audio only file from the video.
  3. Clip the portions I want into individual mp3’s

You can use Audacity with the FFmpeg add-on software and that should open up the sound part of a video.

  1. Get the large video file to my Windows desktop to process it with Audacity.

That is a question, isn’t it?


USB transfer or WiFi transfer.

Add LAME to your computer so you can export MP3.

Drag-select each portion, label each portion then File > Export Multiple….


I would suggest you first extract the audio track from the MP4 (MPEG-4 Part 14) container, using a tool like MP4Box.

It’s quite possible, the audio track is already in MP3 format (MP3 is one of the audio formats supported in MP4 container), in which case a lossy re-compression can be avoided. You could then cut portions out of the MP3 file in a lossless way using mp3DirectCut.

Are you guys saying Audacity won’t do what I want with the file after all? I need to get more software? The mp4 is now on my desktop awaiting dismantling. All I want is selected audio clips from the video in mp3 format. I feel like I don’t speak the right language to understand all the nice suggestions.

No, not saying that, though to support the proprietary formats mp4 and mp3, Audacity requires a couple of plugins (as Gale previously wrote).
To import the mp4 you will need FFmpeg (supports many formats), and to export an MP3 requires Lame.

Instructions for installing:

Excellent - that’s part 1 done.

Have you installed the FFmpeg plugin as Gale suggested? (instructions here:
Once that is installed you should be able to just drag the video file into a new (empty) Audacity window and Audacity should be able to extract the audio from the video (alternatively use the Audacity “File menu > Import Audio” and select the video file.)

Well, what I meant is that it may not even be necessary to re-compress the file in your case! Loading an audio file into Audacity (or any similar audio editor) and then saving it to a lossy format, such as MP3 or AAC, always causes a certain loss in quality. This is called “generation loss”. Thus you should avoid re-compression whenever possible - unless you really have a good reason to do it, of course.

MP4 is a container format, i.e. the MP4 file contains audio and/or video streams. And you can extract (demultiplex) these streams from the container, using a tool like MP4Box. This is a 100% lossless process. It’s also much faster than re-compression. Furthermore, it’s quite possible that the audio stream inside your MP4 file already is in MP3 format. It may also be in AAC format, though.

In case the stream already is in MP3 format and you wish to cut it, you may use mp3DirectCut for this purpose. In contrast to Audacity (or any similar audio editor), mp3DirectCut operates directly on the compressed MP3 bitstream, so no re-compression, and thus no quality degradation. Of course mp3DirectCut does not provide all the flexibility that a fully-fledged audio editor like Audacity does.