(This says it's the full film. YT doesn't seem to have many shorter clips.)
The film is about the 1958 Newport Jazz Festival, the fifth since its founding in 1954. The first one was a minor success, held in a casino. In 1955, Miles Davis played his famous "comeback set" there, and in 1956 Duke Ellington played his comeback set, during which Paul Gonsalves had them dancing in the aisles with a now legendary 27-chorus sax solo. In a smaller, simpler world, that's what it took to make a legend. Of course a young fashion photographer wanting to make his first movie before he was thirty would think of filming the 1958 Festival, especially since the America's Cup races would be on at the same time. All those beautiful pictures of yachts and sails and sparkling blue water. The film is Kodachrome heaven. It's worth watching just for the pictures.
Two bits of background. First, there was a chunk of the American Upper Class who liked to differentiate themselves from the nouveau-riche by taking up abstract art, Stravinsky, "modern dance" and other such stuff as leaves the majority wondering what's going on. Jazz was one of the things they took up, both the more traditional stuff (cf Bing Crosby et al in High Society) and the post be-bop, cool, Third Wave, hard bop and later developments.
Second, the jazz made between about 1945 and 1965 is a man's music: hard, fast, loud, technical, requiring great skill, knowing when to follow the rules and when to bend them, and at the top level, a
Okay. Enter George Avkian https://thefilmstage.com/the-history-behind-jazz-on-a-summers-day-a-landmark-concert-film/ , one of the smartest musical entrepreneurs in the business.
The story is that George Avkian "helped" Stern pick the acts for his film - many of whom were on Avakian's labels - and arranged the clearances. His choices were already famous-famous (Louis Armstrong, Mahalia Jackson) to help get the audiences in; jazz-famous (Anita O'Day, Gerry Mulligan, Thelonius Monk); or juke-box hits (believe it or not, but The Train and the River was a juke-box hit). And Chuck Berry. The background soundtrack was mostly ragtime, and, yes, we get "The Saints".
Any work of art can be interpreted in many ways. My take is that Stern wanted to make a movie, had chosen this subject, and Avakian likely recognised that the film could be a PR opportunity, not just for his acts, but for jazz. The film could present a domesticated and even upper-class face: yachts, and sparkling blue water, and kids playing, and peaceful mixed-race audiences, patrician organisers and audience members, and a guy playing Bach. Exactly the film Stern wanted to make. See? Jazz is American Music, good wholesome stuff for good wholesome people, having a fine weekend holiday. Sometimes art and business can work wonders.
The movie is on DVD and TV streaming services, and the soundtrack is on CD and sound streaming services. Well worth it.