IRVINE, Calif. (AP) — The knock came at night more than 30 years ago. Hugo Van, then a young man, had a chance to flee newly communist Vietnam and walk to freedom.

There were no guarantees, but Van didn’t hesitate to take the risk. With a few hundred dollars, he and his younger sister got a car ride to a Vietnamese village, then a boat to Cambodia and began the trek across barren land until they were caught by Cambodian soldiers. For nearly two weeks, they were held in a camp where they were given wormy rice to eat and Van found himself staring down the barrels of six guns as guards attempted to attack his younger sister.

‘‘Everybody knew: boat or walk,’’ Van, now 57, told his American-born daughter in words she was hearing for the first time. ‘‘When you escape ... you use your life to bet.’’

Van, a retired pressman, had never shared the harrowing tale of his journey with his daughter, Viola, until she began recording it as part of a project to capture the experiences of Vietnamese refugees — many now well into their 70s and 80s — to preserve their memories before it’s too late.

His story is one of 300 being collected by the University of California, Irvine in an effort to create a digitized history of the Vietnamese-American experience and bridge the generation gap between refugees and their American-born children who are helping conduct the interviews, said Thuy Vo Dang, the project’s director.

‘‘They have survived extreme types of experiences — war displacement, the death of half their family, the immigration process, refugee camps — the experiences have left a silence in the community,’’ Vo Dang said. ‘‘When it comes to the home space, it is very difficult to share these stories.’’

The oral history project comes amid new efforts by Vietnamese-Americans across the country to keep elders’ stories alive. Community groups recorded stories in Louisville, Ky., and Austin, Texas, where volunteers amassed 500 video histories that are now being donated to universities. Another oral history project is being considered in Maryland.

In his interview in California, Nguyen Van Lanh, 71, recalled spending nearly eight years in a communist prison camp after fighting in the South Vietnamese military during the war. He was told he would spend a month being ‘‘re-educated’’ by the communist government. But he wasn’t allowed to return home to his wife and six children until 1982 after spending countless days planting sweet potatoes and cassavas as a jungle prisoner and surviving on old rice and whatever protein they could get their hands on — rats, lizards, termites.

It took another decade for him to immigrate to the United States under a humanitarian program aimed at helping former prisoners leave, he recounted in one of the nearly 100 interviews made available for the public to download starting on Wednesday.

The oral histories — which are logged as audio recordings with transcripts and translation into English — are being housed at the school’s Southeast Asian Archive, as well as online. The collection also features interviews conducted in the Austin project, which dates back to 2008.

Nancy Bui, who started that effort, said the idea began two decades ago when her daughter got a failing grade on a paper about the Vietnam War after drawing from her mother’s experiences. Bui spoke with the teacher, who said the curriculum she was given offered a different portrayal of Vietnam’s communist leaders than the refugees did.

‘‘I told my daughter, someday mom will try to do something because your teacher has a point — we have so many stories, we need to tell our story so the world knows what really happened in Vietnam in the war and our journey to freedom,’’ said Bui, president of the Vietnamese American Heritage Foundation.

Nearly 1.9 million Vietnamese live in the United States. It is the fourth largest Asian-American community in the country, according to U.S. Census data, with sizable populations in Orange County’s Little Saigon — located just a short drive away from Irvine.

Many Vietnamese arrived in Southern California as refugees after communists took over the country in the 1970s. Some fled Vietnam by boat on rough seas. Many were sheltered in refugee camps in other Asian countries before being flown to the United States.