For these documentary directors, HBO is the anti-'Predictable Content Channel'

When Oscar winner Alex Gibney sent HBO Documentary Films executives an early cut of his new movie, “Wise Guy: David Chase and the Sopranos,” he was blindsided by the feedback he received.

“God bless HBO, they said, ‘This is so good — make it longer.’ I rarely get that note.”

In the streaming world, documentaries have exploded, with newcomers like Netflix and Hulu chasing the next binge-worthy sensation. But HBO Documentary Films, which started in a nascent form in the late 1970s, remains a distinguished player, regarded as an especially prestigious and director-driven home for nonfiction fare. To understand why, it helps to talk to filmmakers who have recently worked with HBO — including Gibney, whose two-part documentary chronicles both Chase and his groundbreaking series across a swe