It took 46 years for two nights of performances by Aretha Franklin to earn a theatrical release. Director Sydney Pollack initially failed to sync audio to video, and by 2011 the footage faced legal turmoil. The music in the film — released in part on the 1972 album “Amazing Grace” — is familiar. The visuals — left unreleased in 1972 — are not. That Franklin still stuns is a testament to her genius. The “Amazing Grace” album was the peak of Franklin’s recording career. Nothing before it captured the spiritual transcendence, and nothing after it captured Franklin’s vocal dexterity. By the end of the decade, Franklin’s voice had deteriorated, becoming more mellow and less pliable. If “Amazing Grace” is a live album — an uncertain classification given the songs’ multiple takes and studio overdubs — it is a peerless live album, eclipsing later work from Franklin and other artists. The release of the film — also called “Amazing Grace” — is not what Franklin wanted. Despite releasing another live gospel album, “One Lord, One Faith, One Baptism,” in 1987 and “Amazing Grace: The Complete Recordings” in 1999, the singer sued twice — in 2011 and 2015 — to stop the film’s release. By the time of the first lawsuit, the singer had been diagnosed with a pancreatic neuroendocrine tumor, something producer Alan Elliott speculated could have influenced her decision to block the release. According to Elliott, because of Franklin’s onscreen vitality, the film “is really a mortality check, and I can only imagine what it was like for her, being as sick as she was.” Yet Franklin was indifferent to the film even before her cancer diagnosis, telling her biographer, David Ritz, that “if a movie were meant to be, it would happen.” Never mind that when Elliott restored the film, Franklin opposed it. Another account of Franklin’s reluctance to approve the film comes from the bassist Chuck Rainey, who claims Franklin felt “Amazing Grace” was not sufficiently about her, but instead “about James Cleveland, her father, [and] Clara Ward.” The film itself lends some credence to this theory. After Cleveland, the director of the Southern California Community Choir, introduces the Rev. C. L. Franklin — Franklin’s father — and gospel singer Ward, Franklin haltingly begins, then restarts, her rendition of “Climbing Higher Mountains.” This is the only time in the film she asks for a second take. The closest analogue to “Amazing Grace” is probably “Michael Jackson’s This Is It,” another concert film released posthumously against the apparent intentions of the deceased. But where that film is haphazard — literally culled from erratic rehearsals — this one feels finished, the expression of a clear artistic vision. Indeed, the track from the “Amazing Grace” album that required the most extensive studio work, a cover of Rodgers and Hammerstein’s “You’ll Never Walk Alone,” is not in the film. Like the album, the film combines multiple takes, sometimes within the same song. Many of the takes in the film are different from the takes on the 1972 album, but “Amazing Grace: The Complete Recordings” contains full recordings of both nights. More notable than the film’s selections — which include the obligatory title track and reworkings of popular songs — are its omissions. “Give Yourself to Jesus” and Franklin’s reading of Psalm 23 are absent, as is “God Will Take Care of You,” Elliott’s preferred track. Franklin’s most effective mode was interpreter — hearing popular songs and appropriating them. “Respect,” “I Say a Little Prayer,” and “Don’t Play That Song (You Lied)” all became hers. “Amazing Grace” showcases this aspect of Franklin in the medley “Precious Lord, Take My Hand/You’ve Got a Friend,” as well as in her cover of Marvin Gaye’s “Wholy Holy.” The former, beginning in E minor with sparse instrumental backing, owes its vocal arrangements as much to jazz outfit Pretty Purdie and the Playboys as Carole King. The cover of “Wholy Holy,” for its part, disregards Gaye’s rhythms for a mesmerizing arrangement by assistant choir director Rev. Alexander Hamilton. In the film and albums, Franklin’s father claims that “she has never left the church.” This is a common refrain in Franklin’s career — in 2015, she told journalist Gwen Ifill that rather than crossing a line from gospel to pop, “gospel is a constant” in her career. “Amazing Grace” is nonetheless a dramatic departure from Franklin’s secular work. Even if soul adapts elements of gospel, there is a difference between the secular love of “Dr. Feelgood (Love Is Serious Business)” and the spiritual love of “Precious Lord, Take My Hand.” There is also a difference between the emphasis on new material in popular music and standards in gospel. What Franklin does with “Amazing Grace” is transformative, making the secular spiritual and the spiritual popular. In an era defined by religious influence in popular music — from “Ultralight Beam” to “God’s Country” — this message resonates.