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
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. ffmpeg library audacity download mac