After Lynn Schneider’s father died, she received a box of old film canisters from her mother, who had unearthed them from a closet. Had Schneider known that they contained a gold mine of family history, dating back to prewar Hungary, she might not have let several years pass before transferring the film to video.

Lynn Schneider

When she did, she was “stunned” by the black-and-white footage taken by her grandfather Julius, a keen amateur filmmaker who documented his life in Budapest and its surroundings.

“I saw my father as a little boy, running across the grass,” says the Berkeley resident. And she learned more about the romantic relationship of her grandparents in prewar Europe, and the subsequent escape of family members to America.

The films led Schneider on a quest to know more about her family history and the early childhood of her father, Robert. “I was very close to my father, but he rarely spoke about Hungary, and he never spoke in Hungarian.”

 Schneider turned her personal discovery into a 28-minute documentary, “Budapest: An American Quest.” It will be screened, with Schneider present for a Q&A, on Thursday, Jan. 9 at the JCC of the East Bay.

The surprisingly high-quality footage depicts a vanished world: the prosperous Jewish bourgeoisie of Budapest in the 1920s and early ’30s. In these 90-year-old films, the Hungarian capital is a beautiful city of imperial buildings and cathedrals, elegantly dressed people and ice-skating couples on the frozen river. Julius formed a home-building partnership with his brother, and for a while the business prospered.

“They lived very well,” Schneider says of her family in her on-screen narration. (That success would come to haunt her uncle when he revisited Communist Hungary in 1949 and was placed under house arrest as a “prewar capitalist.”)

Kitty and Julius Schneider in Budapest

The films also include footage of Schneider’s grandmother, Brooklyn-born Kitty Weiss, who traveled to Budapest in 1925 on a European cruise. She was just 20 when she met the Jewish “smart set” of the time — fashionable, seemingly assimilated and completely at home in the beauty of Budapest. The role of tour guide fell to  Julius Schneider, who spoke English.

Romance and marriage ensue for Kitty and Julius, including the birth of two sons.

To identify locations, Schneider enlisted the aid of native Hungarians, playing the films over and over. “It was like the Zapruder film,” she jokes (referring to the

8 mm footage of the JFK assassination). “We kept stopping it and saying, ‘What is that?’ ” Budapest was comparatively undamaged in World War II, so it was possible to pinpoint certain locations, she says.

Eventually, Schneider traveled to Budapest and hired a genealogist to help track down some of the places where her grandparents had lived.

The discoveries stirred the memories of aging members of the Hungarian branch of the family, who helped to reconstruct events. Raoul Wallenberg, the Swedish diplomat who saved thousands of Jews by issuing them Swedish passports, makes a brief appearance in the film. So does Howard Hughes, who arranged to evacuate some surviving family members immediately after the war, as a favor to a family friend who worked with Hughes on the experimental D-2 bomber.

Even for people with no connection to Hungarian Jewry, the film is absorbing. It won the grand festival award for best ethnographic film at the Berkeley Video Film Festival last year.

While the discovery of the old films and making the documentary were transformative events for Schneider, she does not indulge in much introspection. “I got to show the world something about my family,” she says simply. “I’m proud of them.”

“Budapest: An American Quest” screens 7 p.m. Thursday, Jan. 9 at JCC East Bay, 1414 Walnut St., Berkeley. $8-$10. www.jcceastbay.org. Also 2 p.m. Jan. 15 at JFCS’ Café by the Bay, 600 Fifth Ave., San Rafael. RSVP by Jan. 9 at (415) 419-3654.