For those who think Hollywood has become a cocaine-and-orgy-fueled cesspool that churns out nothing but garbage, "Babylon" is here to assure you: It was always thus.

Set between 1926 and 1952, Damien Chazelle's psychedelic drama plays out like "Baz Luhrmann's Singin' in the Rain": three loud, lurid, jump-cutty hours in which the movie biz transitions from silent films to talkies to confusion about what audiences want, with random naked people standing in the background of most scenes. The other comparison to a better movie would be "Boogie Nights," which was about the transition from filmed to video porn. "Babylon" pays homage to it in a garish sequence with Tobey Maguire that is meant to recall Mark Wahlberg's nightmarish trip to a drug house while "Sister Christian" blared.

Caution: Even the "nice" trailer contains some naughty language.

Chazelle isn't as skilled a director as Paul Thomas Anderson ("Boogie Nights") is, and his film never achieves the sense that the tiny lives we're watching stand in for bigger social concerns. Chazelle's main characters are Margot Robbie as crass starlet Nellie, Brad Pitt as a Douglas Fairbanks-like silent movie hero named Jack and Diego Calva as Manny, who wanders onto a backlot and vows to do whatever it takes to make it in the movies.

Their lives take dramatic turns, but Chazelle seems less interested in characters or stories than in the evolving nuts-and-bolts of moviemaking. We get scenes that show the difficulties some actors had when audiences could hear their voices (a la "Singin'") and the frustration of waiting for perfect lighting and the vicissitudes of stardom, which see Nellie and Jack fall in and out of favor at the whim of gossip columnists such as the one played by an underused Jean Smart.

Chazelle packs in allusions to tons of real Hollywood lore, including the downfall of Fatty Arbuckle and the rise of Clara Bow, and it's obvious that he loves the seedy, self-destructive glamour of the world he and his designers depict. But a lot of that was done, better, in Joel and Ethan Coen's "Hail, Caesar!"

"Babylon" has the feel of a movie the creators hoped would come together in the editing room but didn't. Stories and people appear and disappear throughout, often without making much of an impression. When one key supporting character dies, we're supposed to be upset, but I wasn't even sure who he was.

"Babylon" deserves credit for taking big swings, but it's usually unclear what it's swinging at. It's engaging from scene to scene — although it's three hours long, it's never dull — but the character trajectories are so familiar that they don't make much of an impact. For all the trashed parties, failed movies and torpedoed careers it depicts, all "Babylon" really has to tell us is that the only way to succeed in Hollywood is to get the heck out.

'Babylon'

** out of 4 stars

Rated: R for graphic nudity, violence, drug use and sex.