This was shot in 1974, the same year I saw Bonnie Raitt in concert in Waterville, Maine. She was just getting started as a prominent musical fixture.
I lived in Waterville at the time and was familiar with Bonnie because my college friend, David Mathre, had her first album, which he played relentlessly in our dorm in Eugene. David had set out to learn every tune on it note for note, which he succeeded in doing.
This is her cover of the great John Prine song, and she certainly does it justice.
During the Waterville show, which I watched through binoculars in a venue much like this one, Bonnie would occasionally grab her guitar player's ass after a particularly blistering solo, which led me to believe he was her lover or she just really liked how he played--or both.