“The Black Power Mixtape 1967-1975,” among other things an extraordinary feat of editing and archival research, takes up a familiar period in American history from a fresh and fascinating angle. In the late 1960s and early ’70s, Swedish television journalists traveled to the United States with the intention of “showing the country as it really is.” Some of the images and interviews they collected have been assembled by Goran Hugo Olsson into a roughly chronological collage that restores a complex human dimension to the racial history of the era.

The film begins at a moment when the concept of black power was promoted by Stokely Carmichael, a veteran of the freedom rides early in the decade, who, like many young black activists, had grown frustrated with the Gandhian, nonviolent philosophy of the Rev. Dr. Martin Luther King Jr. Carmichael, who later moved to Guinea and took the name Kwame Ture, is remembered for the militancy of his views and his confrontational, often slashingly witty speeches, but the Swedish cameras captured another side of him. In the most touching and arresting scene in “Mixtape,” he interviews his mother, Mable, gently prodding her to talk about the effects of poverty and discrimination on her family.

That quiet conversation is a reminder that the inflammatory rhetoric of the black power movement, with its talk of revolution, national liberation and armed struggle, had its roots in bitter experience. And while “The Black Power Mixtape” tells a story of defiance and pride, it is also a tale of defeat, frustration and terrible destruction. The assassination of Dr. King, the grinding toll of the Vietnam War, the Attica prison uprising, the spread of heroin in the ghettoes of northern cities: these are not chapters in a tale of triumph.