Liz Garbus' "What Happened, Miss Simone?" begins with footage of Nina Simone taking the stage at the 1976 Montreaux Jazz Festival. It was a performance that simultaneously represented a comeback from self-imposed exile for the iconic chanteuse, but also has been used as an example of the mercurial, erratic and occasionally bizarre work that characterized the middle of Simone's career. 

Simone stands in front of her piano and takes a prolonged bow. She stares into the audience and seemingly off into space. There's almost no way to read  her. Is she embracing the applause? Is she alienated in the spotlight? Is this her dream? Is it her nightmare? 

It's a perfect prelude to the film's title, which comes from a 1970 Redbook piece by Maya Angelou.

That enigmatic opening and the interrogative title lead, somewhat disappointingly, into a rather conventional cradle-to-the-grave documentary.

But even if there's a sense that a woman as uncontainable as Nina Simone deserved a documentary less eager to contain her in easy-to-understand terms, "What Happened, Miss Simone?" remains engaging by virtue of the wealth of archival and concert footage Garbus has assembled.

One of the Opening Night films at this year's Sundance Film Festival, "What Happened, Miss Simone?" is screening out-of-competition here and will premiere on Netflix this spring.

[More after the break...]

The many shadings of Nina Simone's career and life could have made for five or 10 tightly focused documentaries.

There's the North Carolina-born piano prodigy forced to become one of the great jazz/blues vocalists of all-time because her race prevented her from studying the classical music she loved.

There's the hit recording artist who turned her attentions to the Civil Rights Movement after the church bombing in Birmingham.

There's the increasingly militant political activist who stopped advocating non-violence as her movement's leaders were killed, jeopardizing her commercial fortunes. 

There's the ex-pat who fled to Liberia and gave up music (and gave up paying her taxes).

And then there's the artist who returned from that exile, battled mental illness and breast cancer, published a successful autobiography and had her cover of "My Baby Just Cares for Me" used in a Chanel No.5 perfume ad.

And none of that is getting into the more personal sides of Simone's life, including her troubled marriage and relationship with her daughter Lisa.

Telling all of those stories in 100 minutes is a pretty simple recipe for short-changing some aspects, over-relying on simplistic causality or, as was often the case in "What Happened, Miss Simone?", both. 

The speed, for example, with which the documentary nods at Simon's manic-depression/bi-polarity before offering a talking head suggesting that her real problem was being a strong woman at time when strong women were threatening is baffling. It's almost like Garbus is afraid that if she attributes too much of Simone's struggles to mental illness, we'll somehow respect her less, or at least respect the crushing difficulties of her position less. 

And Simone's ties to the Civil Rights Movement gain extra power due to proximity to "Selma" and to recent unrest in Ferguson and New York City, but that extra currency makes up for a lot of very loose sketching, like the cross-cutting of essentially stock civil rights footage with a live performance of "Backlash Blues." Personally, I could have watched a whole movie about Simone's place among the '60s black intelligentsia, from Langston Hughes to Lorraine Hansberry to gatherings with Malcolm X's family, but you get moments of that and then it's on to the next thing.

Garbus' central structural gambit is telling as much of the story as possible in Simone's own words, culled from interviews, some never-before-heard. It's a great idea and, at times, there's a welcome candidness from the approach, but when it's just Simone narrating a stream of events from her life, it isn't appreciably better than using a third-party narrator. And while Simone gave many interviews during and about the first chapters of her life, basically from Liberia on has to be entrusted to friends and loved ones and, as a result, feels much less illuminating. 

What Garbus does well, and what should help "What Happened, Miss Simone?" have a long lifespan, is honor Nina Simone as an incomparable performer.

Musical biopics like this often jump from performance snippet to performance snippet, never letting you luxuriate in a full song. 

Garbus rarely starts a song without finishing it. Sometimes talking heads or Simone herself talk over the performance a bit, but the interruptions usually add appreciated commentary to the songs without upstaging. Full songs from early in her career let experts parse both the tone and emotion that make Simone so unique. You can track Simone's increasing comfort as a singer through performances at the 1960 Newport Jazz Festival and, subject of particular crowd amusement, on "Playboy's Penthouse," introduced by a young Hugh Hefner. It's one thing to have people mention or discuss Simone's political awakening, but it's much better when we bridge between several performances of the sublime "Mississippi Goddam," with Dick Gregory admiring the courage of the sentiment. 

The integrity of the performances are even honored when it becomes a challenge to see Simone's genius. There's the awkwardness of that 1976 Montreaux performance, which she interrupts to chide an audience member for standing up. There's a later performance in which it has to be pointed out that she's somehow singing one song and playing another on the piano.

When Garbus lets Simone show us why she's special "What Happened, Miss Simone?" is successful and vital. The songs say and illustrate so much that the rudimentary chronological beats become a redundant imposition. In the recitation of life events, "What Happened, Miss Simone?" feels like a list of Wikipedia headings. In the performances, you hear and feel nuances that answer Maya Angelou's question.

A long-time member of the TCA Board and a longer-time blogger of "American Idol," Dan Fienberg writes about TV, except for when he writes about movies or sometimes writes about the Red Sox. But never music. He would sound stupid talking about music.