For all the beautiful and lovely music Whitney Houston gave us, for all those soaring notes she hit, the documentary “Whitney. ‘Can I Be Me’ ” is a nearly joyless and melancholy piece of work.

Because we know how it ends. Because we know about Houston’s lifetime of troubles, from the tumultuous relationships to the family fractures to the years spent battling addictions.

Directed by Nick Broomfield, architect of sometimes salacious but admittedly very watchable documentaries about Kurt Cobain and Courtney Love; Biggie and Tupac; Hollywood madam Heidi Fleiss, and serial killer Aileen Wuornos, among others, “Whitney. ‘Can I Be Me’ ” begins at the end: a 911 call from the Beverly Hilton in 2012, after Houston was found dead in a bathtub at the age of 48.

The news of Whitney’s death was stunning, but not shocking. Tragic, but not completely unexpected. By then, everybody knew about Houston’s demons.

Broomfield circles back to Houston’s childhood in New Jersey, giving us archival footage of an adolescent Whitney singing in church and telling the story of how she was guided to early stardom by her domineering mother, singer Cissy Houston, and then Clive Davis, the controlling mastermind of Arista Records.

Whitney Houston is seen as a girl in a photo from “Whitney. ‘Can I Be Me.’ ” | REX/Shutterstock

It was Davis who steered Houston away from R&B and soul and toward a more “mainstream” sound, designed to appeal the broadest possible audience. For perhaps the first time but certainly not the last time in her career, Whitney asked, “[But] can I be me?”

Some of the most compelling scenes include previously unseen concert and backstage footage from Houston’s 1999 European tour, which would become her last major worldwide venture of such scope. Shot by the German director Rudi Dolezal for a concert documentary that was never finished, the footage shows a sweat-drenched Houston hitting the highest, nearly unreachable notes on “I Will Always Love You,” bonding with her band and backup singers backstage — and navigating her complicated relationships with her husband Bobby Brown and her longtime assistant and best friend Robyn Crawford.

It has long been maintained Crawford and Houston were lovers. “Can I Be Me” addresses the rumors but does not answer them definitively. What we know for sure is Brown and Crawford loathed one another, and Whitney was often caught in the middle.

(Neither Brown nor Crawford agreed to be interviewed for the documentary.)

One associate of Houston’s says she “died of a broken heart.” Others say she was given a gift from God and didn’t properly treasure it. Some point to the toxic relationship with Brown, in which the two enabled one another. (Houston brought drug abuse to the table. Brown introduced alcohol into the relationship. Each indulged in the other’s addiction, making for a volatile and destructive mix.)

Perhaps the most heartbreaking scene in the film shows Houston with her then 6-year-old daughter Bobbi Kristina onstage.

Bobbi Kristina looks like she doesn’t want to be there. Whitney looks like she never wants to leave the stage, because by then the stage was the only place she could hide from all the madness dominating her personal life.

★★★

Showtime presents a documentary directed by Nick Broomfield with Rudi Dolezal. Running time: 105 minutes. Screens at 8:30 p.m. Friday and 6 p.m. Saturday at the Gene Siskel Film Center as part of the Black Harvest Film Festival, and premieres Aug. 25 on Showtime.