You can install a software called "Format Factory" in your computer. This software has the function of video format conversion, which can convert mp4 format into pmvb or other formats. You can also convert the video of the square dance into an audio file, that is, extract the dance music without looking for music everywhere, which is very easy to use. Might as well try.
I'll help you convert a song "Mountain Red" and send it to your email. Let's see if it works.