Near the start of the documentary, Down: Inside Rock in the PRC, co-director Andrew David Field asks Kang Mao, the outspoken female lead singer of the Subs: "So, what do you think of Cui Jian?"

"Cui Jian is handsome. Cui Jian is the godfather," the singer replies.

"How about the Subs? Ever heard of that band?" Field continues.

Kang says: "Nobody has heard of the Subs. People just know Cui Jian. The Subs are a bit strange."

The filmmaker was on a train with the Subs to Changsha, capital of Hunan province, where they would perform with Cui Jian, who's known as the "godfather of Chinese rock", in 2007.

Field has been in China on and off for more than 25 years, since his first visit in 1988. He has long been familiar with Shanghai's jazz scene and watched some Chinese rock bands in Beijing in 1996. Most were cover bands, doing renditions of songs by such Western bands as Nirvana and Oasis.

It was a far cry from his experience on the road for two years with the Subs, with whom he traveled to such cities as Hubei's capital Wuhan, Changsha and Shanghai.

He became very familiar with how the Subs traveled and were treated by concert organizers.