On a recent Thursday evening, a blue-and-white GMC motor home with tinted windows was parked in front of the Stephen Sondheim Theater on West 43rd Street. Cables ran from it, up over the theater marquee, through a window, and down into the theater, where they plugged into three cameras set up to record the evening’s performance of “The Trip to Bountiful,” which has four Tony nominations heading into Sunday night’s awards ceremony.

Inside the vehicle, a mobile production crew was gearing up for the 7 o’clock curtain. “Tonight we have the audience as a potential performer,” said the sound engineer, Larry Loewinger, who had aimed two microphones at the crowd in case it sang along with a hymn in the second act, as had become common. The shoot’s director, Steven Moskovic, sat facing the monitors, looking over the script, waiting for his cue.

“Roll tape, please,” he said when he got the two-minute warning from the production stage manager inside the theater. “Three, two, one, fade up.” On the main monitor before him, a shot of the playbill appeared first, followed by an image of the audience and stage as opening credits rolled. Then the curtain went up.

Though the preparations were elaborate, the “Bountiful” video was not destined for a commercial network broadcast or even PBS. It was one of the 50 or more live theater performances — Broadway, Off Broadway and regional theater — recorded each year for the Theater on Film and Tape Archive, part of the New York Public Library for the Performing Arts, at Lincoln Center.