“Tangerine” opens Friday in major cities (no Madison date has been announced yet). R, 1:28, three and a half stars out of four.

Don’t judge an L.A. trans prostitute unless you’ve walked a mile (or 50 yards) in her high heels. That’s the message of writer-director Sean Baker’s enormously entertaining and empathetic feature “Tangerine” which gives a collection of marginalized figures some wit, passion and even some dignity.

Baker’s last film “Starlet” similarly looked at a young porn star’s life with a similar curiosity and lack of judgment. In “Tangerine,” the heroines are Sin-Dee (Kitana Kiki Rodriguez) and Alexandra (Mya Rodriguez), two African-American trans prostitutes working among the strip malls and donut shops of Los Angeles. The open scenes are a riot of color, noise and motion. Best friends Sin-Dee and Alexandra strut down the street, keeping up a constant stream of patter, the soundtrack thumping, the camera following along or swinging around beside them as if in puppy-dog awe. Baker famously shot the film on an iPhone 5s (not even a 6!) and the result is both cinematic and intimate, the wide-screen compositions pulsing with vibrant colors and kinetic energy.

Sin-Dee is on a mission that drives the film. Freshly released on Christmas Eve after a month in jail, Sin-Dee catches wind that her boyfriend/pimp Chester (James Ransone. continuing a string of deluded lowlife roles stretching back to Season 2 of “The Wire”) has cheated on her with a fellow trick, Dina (Mickey O’Hagan). While Alexandra prepares for her big singing debut (at a club where she has to pay to perform), Sin-Dee hunts down Dina and Chester.

Along the way, we’re also following one of their regular johns, an Armenian cab driver (Karren Karagulian) fleeing his family’s Christmas dinner. (There are some funny glimpses of his passengers, including veteran character actor Clu Gulager.) All the characters finally intersect at a famous little L.A. shop called Donut Time for a reckoning that’s both farcical and bittersweet.

Baker injects his film with a lot of humor and life (“C’mon, it’s Christmas,” a john argues while trying to haggle down the price of service), but he never presents the world of Sin-Dee and Alexandra as anything worthy of mockery. A trip into a “brothel” — a motel room with a trick in every room, including the bathroom — illustrates the sad and desperate lives of these people. Baker doesn’t allow us to step back, either visually or narratively, and by being fully immersed in this world we see their humanity. Everybody has an inner life; I think every character gets a quiet moment when they kind of go inside themselves a little, as if suddenly seeing themselves clearly.

After all the constant chatter, “Tangerine” ends beautifully with a quiet scene between Sin-Dee and Alexandra in a laundromat, a funny and sweet act of Yuletide gift-giving that strangely reminded me of O. Henry’s “Gift of the Magi.” It underscores the bond beneath the bluster, as well as showing that however confused or judgmental others might be about them, they know exactly who they are in this world.