This movie tries to tell the story of Janis Joplin's rise to stardom and her ultimate and rapid fall. The movie has two problems: First, like almost all documentaries involving vocalists, it drives one nuts that so many songs are started and not finished, but instead are interrupted by the supposed story that is far less interesting than the son; and second, at least in the first 45 minutes, largely perhaps because of the age or debilities or lack of analytic abilities of the interviews of her contemporaries, you are left with very little if any insight into the cause of her problems. Her music is electric and fabulous. This movie does not do it justice.
IMDb Link to Janis: Little Girl Blue