This video explains how to install the FFMpeg codec library for Windows. This will allow you to open m4a audio files.
On this page of the site you can watch the video online Audacity FFMpeg codec install for Windows with a duration of hours minute second in good quality, which was uploaded by the user Derik Gray 30 January 2015, share the link with friends and acquaintances, this video has already been watched 54,822 times on youtube and it was liked by 944 viewers. Enjoy your viewing!