VLC is a Free and Open-Source multimedia player that plays almost all Media Files. The VideoLAN Team have included a good feature that allows users to Convert supported Media Files to many Media formats with simple clicks. It also allows the conversion of Video Files to Audio files by extracting the main Audio/Sound from the Video stream. It supports MP4, Webm, TS, OGG, ASF, MP3, FLAC, CD, AAC and other formats. All you need to do is to follow this step-by-step tutorial as I will show you how to do that.
How to Convert Media Files Using VLC
3) Click Add… and Select the Media Files you want to convert, then Click Convert / Save