One of the world's all-time greatest jazz singers for over 50 years and the queen of scat singing, Ella Fitzgerald has been the subject of numerous documentaries and performance videos. During the '50s, '60s, and '70s, she often appeared on television variety shows, daytime programs, and in specials. During the '70s, her voice could be heard shattering glass on Memorex ("Is it live or is it Memorex?") commercials. Earlier in her career, Fitzgerald made the occasional feature film appearance beginning with Ride 'Em Cowboy (1942).