The following three clips are from the 1975 feature film "That's the Way of the World." At this point the Earth, Wind & Fire soundtrack to the film is better known than the actual movie, which was out of print until recently (yours truly picked up a VHS copy off of eBay a few years back).
Actually, I had the EWF album for awhile before I noticed that it was a soundtrack to a movie. Then it was a few more years before I got my hands on the movie. It's not great, but it is interesting to see the recording industry portrayed in 1975 at the peak of its excesses. The movie follows Harvey Keitel, a producer, who is hoping to break his pet project, "The Group" (EWF), but instead gets saddled with producing a lame-O vocal group in the mode of the Carpenters, but far less musically interesting. Their song sounds like a demo for the Ren & Stimpy "Happy, Happy, Joy, Joy" song of many years later.
I have three clips here. The first is the title credits where "The Group" are tuning up and then recording the title song in the studio. The second clip is of "The Pages" song which is not so good but I like how the director, Sig Shore of "Superfly" fame, films the recording session to give the viewer a sense of how songs were recorded and produced. The final clip is of EWF playing at a roller disco. The sound and picture are a bit murky, but when else are you personally gonna see EWF performing at your nearest roller disco.