To unlock the full potential of your audio editing on macOS, you must install the FFmpeg library . By default, Audacity can only handle a limited number of formats like WAV and AIFF; however, with FFmpeg, you can import and export a vast range of audio and video formats, including M4A (AAC), AC3, AMR, and WMA.
Audacity does not include FFmpeg directly due to legal and licensing restrictions, so you must download it from a trusted external source. Audacity: Fix Error importing: "FFmpeg library" missing ffmpeg library audacity download mac