Very good, narration-free documentary that intercuts performance footage with interviews. This is a straight compilation film, using then-existing material. I don't think there was anything shot specifically for this film.
For such an electric talent, it is especially good that the directors just stay out of the way, and not try to staple significance, meaning or whatever to their subject. They just let Janis Joplin sing and speak for herself.
And, that's the best thing you could possibly do for a Janis Joplin doc!
Janis is worth a watch, but I would say you have to be a true fan of hers to really like it. There's not much in the way of substance, so if you like to watch documentaries on icons like Janis for their stories and facts on them, this isn't the movie for you. I would have liked the movie to go that route a little bit more than it did, but as it is, Janis and her performances are enough to hold this documentary up. So fans of the genre and of Janis should give this one a watch. If anything watching her live in concerts will just make you more of a fan then you already were.