FREEZE FRAME: “The Birth of a Nation,” “The Girl on the Train,” “The Great Gilly Hopkins”

“The Birth of a Nation” is Nate Parker’s controversial but powerful film about the educated slave Nat Turner who became a pastor and led an ill-fated slave revolt in 1831. Parker wrote, directed, produced and stars as Turner in this unflinching look at the horrors of American slavery. While the violent content is certainly disturbing, the emotional force and the importance of the story help make up for some filmmaking flaws. It’s vibrant enough to start some meaningful conversations. “The Girl on the Train” is an adaptation of the bestselling thriller. Emily Blunt plays an emotionally disturbed alcoholic who may or may not have seen evidence of a crime during her daily train commute. The narrators of this story are unreliable, so the mystery is a bit convoluted. Blunt is terrific in a difficult role that requires her to spend most of the film’s 112 minutes in tears. As this trashy train comes to its final stop, however, it may generate more laughs than chills. “The Great Gilly Hopkins” is an adaptation of the 1979 National Book Award winner for children’s literature. On screen, however, it comes off like a soppy 1979 After School Special. Sophie Nélisse (NAY-less) plays Gilly,…