Bass player and composer Marcus Shelby will perform an excerpt from his Creative Work Fund-supported piece, Gwah Gai (Crossing the Street), a collaboration with visual artist Flo Oy Wong and API Cultural Center, at the Chinatown Music Festival, Saturday, August 17, 11-5 p.m. at Portsmouth Square in San Francisco’s Chinatown. Admission to the festival is free. Shelby is scheduled to perform at 2:30 p.m. For more information, visit the Chinese Culture Center website.