It’s about the country-music pioneers and appears to have been produced for Oregon Public Television. I got it from the library and watched it this evening.
HIGHLY recommended! 
Even if you don’t like country music, it’s a fascinating story and great music knows no genre.
Watched it as soon as it became available on Netflix. Second the recommendation! This is about as American as music gets. My grandparents and some aunts used to sing some of these and other “hill people” songs and sometimes made up their own. Interesting love story mixed into this documentary too, though it’s not the main storyline. I really enjoyed this one.