"They learned their art forms from the older generation and are still performing in remote villages. The art forms, both sounds and folk stories, were born out of local daily life and connect with everything such as the weather, landscape, dialects and food.

"They are not famous or wealthy. But they are keeping the great art traditions alive," Su adds.

He says that when he realized Western rock music "wasn't enough" to convey his thoughts, Chinese folk arts showed him the way.

Three young film directors condensed the 1,600 hours of footage shot over 2016-18 into the documentary of 98 minutes.

Ke Yongquan, 30, who was born and raised in Wuchuan, Guangdong province, is one of them. He had not visited Northwest China before shooting the documentary.

"We worked on the post-production for a whole year," Ke says. "While shooting the documentary, we lived with the folk artists. They live differently from people in bigger cities. Now, I miss them and our days together, especially near the Yellow River."