SAN FRANCISCO, Sept 25 Video gamers who live-stream their matches online and the throngs of fans who tune in daily to watch them swarmed a first-of-its kind convention in San Francisco on Friday, as interest swells in the medium of online video game broadcasting.
Utilize the input text as a context reference, choose the right relationship between 'medium' and 'San Francisco' from the options.
Options: manufacturer, platform, location of formation, headquarters location