Bobby Brown, Cissy Houston remember Whitney Houston in powerful Whitney trailer

Whitney Houston's eternal impact on culture continues to shine in the new, full-length trailer for the upcoming documentary about her life.

Released Wednesday morning — just ahead of Whitney's out-of-competition world premiere tonight at the 2018 Cannes Film Festival — the extended preview features rare home movies and concert footage as well as intimate interviews with some of Houston's closest companions.

"Her voice, I was totally knocked out," says Clive Davis, the music industry executive who had a hand in launching her global career. Houston's brother, Gary Garland, continues: "There were always a lot of secrets. When you don't resolve things and you don't deal with things, they never go away."

The teaser then delves into Houston's personal life, particularly her rocky relationship with substance abuse, her turbulent marriage to Bobby Brown, and her alleged romantic entanglement with longtime friend Robyn Crawford.

"Robyn was her safety net. Bobby was jealous," an unidentified voice observes. Another adds: "His heart was, he wanted to be on the stage. He wanted to be in the forefront, and eventually she stepped down to lift him up."

The trailer isn't all serious, however, as it also includes glimpses of Houston's signature no-holds-barred approach to critiquing her peers. "Paula Abdul ain't s—," she says in what appears to be a home video. "That girl is singing off-key on the record."

Finally, Brown and Houston's mother, Cissy, appear to get emotional while discussing the late pop icon.

"She was beautiful," Cissy says. "[She sang with] heart."

Whitney debuts July 6 in theaters nationwide via Roadside Attractions and Miramax. Watch the new trailer above.