“What was good is that the team of Sundance waived the fees,” Mr. Nyrabia said.

Shot between 2011 and 2013 and distilled from 300 hours of footage into 87 minutes, “Return to Homs” chronicles the Syrian conflict as seen largely through the eyes of Mr. Saroot, a 19-year-old goalkeeper and singer who put aside soccer to lead protests against President Assad in Homs, Mr. Saroot’s hometown and long a cradle of anti-Assad grievances. The early scenes show Mr. Saroot orchestrating chants against Mr. Assad at street rallies during the first giddy months of the conflict, energized by the infectious spirit of Arab Spring revolts in Tunisia, Egypt and Libya.

Using an assortment of digital cameras including Handycams, Mr. Derki and Mr. Nyrabia captured raw scenes of combat, dead children and grieving parents, as well as Mr. Saroot’s singing, serious injuries and moments of despair. The filmmakers followed Mr. Saroot and his colleagues, documenting the government’s increasingly violent response to their resistance, their decision to arm themselves, the shelling and bombing that razed their homes and their day-to-day struggle, scrounging for food and clothes abandoned by civilians who fled what had become a war zone.

Mr. Nyrabia said the filmmakers had spent much of the time living with Mr. Saroot and his friends in the rubble of their neighborhood, recharging their phones and laptops from car batteries and portable gasoline generators. They risked their lives to sneak in and out past army checkpoints, and taught Mr. Saroot’s colleagues how to use Handycams when it became too dangerous for the filmmakers to remain in Homs. The footage was smuggled out.

There were some lighter moments, Mr. Nyrabia recalled. When a missile hit a street in the Old City neighborhood, the explosion created a crater and ruptured an underground drinking water pipe. “So the big hole became a swimming pool, and all the children started to swim, and it became like their joy in summer,” he said. “These things do happen.”