"Beta" can be used to refer to several consumer and professional videotape formats developed by Japan's Sony Corporation. Although similarly named, they are very different in function and obsolescence.
Betamax was the name of a domestic videotape format developed in the 1970s and 1980s. It competed with the Video Home System (VHS) format developed by the Japanese Victor Company, to which it eventually succumbed. The Betamax format was also marketed Betacord by (Sanyo); some cassettes were simply labeled "Beta." Betamax lost in the market and is an oft-used example of a technically superior solution that failed due to market forces.
Betacam, including Beta SP and DigiBeta, is a family of professional videotape formats launched in 1982 that was the de facto standard for professional video, advertising, and television production through the 2000s. The formats outlasted analog NTSC television, and their scarcity today is because the industry has moved to HD formats.