How to Convert M4A to MP3 in Audacity: Complete Walkthrough

Why Audacity Won't Open M4A Files Out of the Box

When you attempt to drag and drop an Apple M4A file (AAC audio) into a fresh installation of Audacity on Windows 10 or Windows 11, you will likely encounter this frustrating dialog:

"Audacity cannot open this file. To open such files, you need to install the optional FFmpeg library..."

Because M4A is an MPEG-4 container utilizing AAC encoding, open-source software licenses prevent Audacity from bundling the proprietary AAC decoding codec natively. Here is how to install the required library and convert your files in under 2 minutes.

Step 1: Install the FFmpeg Library for Audacity

1. Open Audacity and navigate to Edit > Preferences (or press Ctrl + P on Windows; Cmd + , on Mac).
2. Select Libraries from the left sidebar menu.
3. Under FFmpeg Import/Export Library, check if FFmpeg is located. If it says "FFmpeg Library Version: (not found)", click the Download button.
4. This opens the official Audacity FFmpeg installation page. Download the recommended ffmpeg-win-x.x.x.exe (or pkg for Mac) and run the installer.
5. Return to Audacity Preferences, click Locate..., and Audacity will automatically detect avformat-59.dll. Click OK.

Step 2: Import Your M4A Audio File

Once FFmpeg is configured, you can import any M4A file effortlessly:

• Go to File > Import > Audio... (or simply drag and drop the .m4a file directly into the Audacity workspace).
• The blue stereo audio waveform will render immediately.

Step 3: Export as High-Quality MP3

1. Navigate to File > Export > Export as MP3.
2. Under Format Options at the bottom of the export window, configure the following settings:
   • Bit Rate Mode: Preset or Constant (CBR)
   • Quality: 320 kbps (Insane) for best sound, or 256 kbps (Extreme)
   • Variable Speed: Fast
   • Channel Mode: Joint Stereo
3. Click Save. Audacity will open the Edit Metadata Tags window where you can preserve or customize the Artist Name, Track Title, and Album.
4. Click OK to finish rendering your MP3 file!

Batch Converting Multiple M4A Files with Audacity Macros

If you have an entire album or playlist of M4A files to transcode, you don't need to convert them one by one:

1. Go to Tools > Macros... in Audacity.
2. Select the built-in MP3 Conversion macro.
3. Click Files..., select all your M4A files, and click Open. Audacity will automate the conversion for every file in sequence.