FC2Video

In this video, you can learn an easy and fast way to extract the audio from multiple videos all at once, so you don't need to convert a video to an audio one by one.
The tool used is called WonderFox HD Video Converter Factory Pro. It can extract audio from any video and output it to MP3, AAC, M4A, Ogg, WAV, FLAC, and more. For more details, you can refer to this article: https://www.videoconverterfactory.com/tips/batch-extract-audio-from-video.html

Software official site: https://www.videoconverterfactory.com/hd-video-converter/