Students in the after-school law club at Murry Bergtraum High School at Lower Manhattan started taking video cameras out to South Street Seaport and Downtown Brooklyn a year ago, asking everyday New Yorkers about their perceptions of police officers and teenagers.

It was part of an after-school project that aimed to change perceptions about both groups.

Now, the project that started as an activity sponsored by the After School Corp.’s Community Justice Project has been transformed into a short documentary, which will debut this weekend at TriBeCa Cinemas as part of the TriBeCa Film Festival.

“I’m excited, but at the same time I’m nervous,” one of the students, Julianna Staten, 17, said. “I want people to like it.”

The documentary, “Us & Them, NYC’s Future vs. NYC’s Finest: Trying to Co-Exist,”is one of 10 short films by city schoolchildren that will be shown Saturday in a program called “Downtown Youth Behind the Camera,” which is part of the TriBeCa Family Film Festival.

“It’s very important because inspiration has to begin somewhere,” the creative director of the family festival, Peter Downing, said. “Inspiration plants itself early, and it’s never too early to acknowledge that and to foster that, and hopefully to inspire them or attempt to inspire them.”

The Murry Bergtraum students who created “Us & Them” have had mixed experiences with police officers.

One student, Jamie Felix, 17, said that in January a team of police officers near his home in Brooklyn mistook him for a crime suspect. He said they patted him down and questioned him.

“They didn’t believe me, they followed me home. I felt like I was a suspect and I wasn’t,” he said. “The person they were looking for probably got away.”

Another student who worked on the project, Janet Huang, 17, said she has had positive experiences with police officers. She said that when she was in seventh grade, an officer helped one of her best friends who had been threatened.

The students said they weren’t sure if their perceptions of police officers changed as a result of working on the project, but they said they would like the film to lead to discussion.

Ms. Staten said she hopes viewers will talk about “what both sides do to cause this friction going on between youths and police officers.”

Films by teenagers were first screened by the film festival last year. This year, some films by schoolchildren will play as part of the family festival at 11 a.m. and 1 p.m. on Saturday. Others are part of the regular film festival, in a portion called “Urban Truths” screening next Friday.