On paper, “Pirate Radio” already has the groundwork for a compelling viewing experience. Released earlier this year in the UK under a different title (“The Boat That Rocked”), the film is the second directorial project of Richard Curtis, who previously pioneered the underrated niche genre of gender-neutral date movie with “Love Actually.” Like that movie, “Pirate Radio” also features a large ensemble cast of established actors, among them Philip Seymour Hoffman, Kenneth Branagh, and Bill Nighy. But even though the film succeeds with a funny script and top-notch acting performances, those elements take a backseat to what the film is ultimately about: the music.

The year is 1966, and despite England’s successful production of some of the most famous rock ’n’ roll bands in the world, the national British radio only plays two hours of the music per week. To combat this, a group of DJs have established a radio station on a small freighter in the middle of the North Sea. Here they cohabitate while playing rock ’n’ roll 24/7 with a listener rate—according to the film—constituting half of the country’s population at the time. The film begins with the arrival of Carl (Tom Sturridge), who has been sent by his mother to the boat after being expelled from school, in the hopes that he may spend more time with his godfather, Quentin (Nighy), Radio Rock’s nutty station manager. The ship’s eclectic personalities—including The Count (Hoffman) and Dr. Dave (Nick Frost)—have popular consensus on their side, but the boat is under legislative siege from the government. Their fiercest opponent is Minister Alistair Dormandy (Branagh), who is committed to shutting down “the drug takers and the lawbreakers and the bottom-bashing fornicators of this recently great country.”

“Pirate Radio” puts the music center stage. Over its two-hour running time, Curtis has assembled a massive classic rock playlist of over 50 songs that never feels out of place against the on-screen action. Classics like “My Generation” and “Jumping Jack Flash” are immediately identifiable, but lesser known performers like The Hollies or Darlene Love fit just as well. Occasionally, Curtis takes a more literal approach; Cat Stevens’ “Father and Son” plays during a moment between Carl and his newly-discovered father, and The Turtles’ “Elenore” echoes the name of the girl who one of the characters ends up marrying. But the songs are so strong and so catchy that it’s hard to care when such straightforward connections are created between music and plot. It is clear that “Pirate Radio” is a love letter to rock ’n’ roll’s golden era and its sweeping influence, complete with an end credit sequence displaying every major album of the last 40 years.

Aside from a superb soundtrack, the film’s other strength is its wonderful cast of character actors. Hoffman remains at his brashest and bawdiest as an American DJ, a stark opposite from Nighy’s prim, if slightly spaced-out, British gentleman. Unquestionably, though, the funniest performance comes from Kenneth Branagh as a viciously polite British official intent on destroying Radio Rock. His outraged caricature is particularly evident during a scene in which he casually threatens to outlaw one of his subordinate’s haircuts. Nick Frost’s (“Shaun of the Dead”) portly and shameless ladies man, Dr. Dave, consistently cracks jokes and snarky comments, despite being of little importance to the film’s plot. Another character named Thick Kevin (Tom Brooke) justifies his namesake during a frustrating game of Taboo; in the hopes that his teammate will know exactly who he means, he describes Jesus as a nice guy with a lot of friends who didn’t wear shoes.

The film’s narrative of a small group of rebels fighting against the government is somewhat bland, but rarely, if ever, does the plot overshadow the characters of the film. The final segment of the film devolves into an unnecessarily long action sequence a la “Titanic,” but the movie ultimately ends on an upbeat note, and this feel-good conclusion works; there is a deep gratification in seeing such likeable characters succeed.

In the midst of one of the station’s more stressful crises, The Count muses that “all over the world, young men and young women will always dream dreams and put those dreams into song.” While at times overly sentimental, “Pirate Radio” and its sprawling soundtrack capture the freewheeling spirit of a transformational era.