The software giant joins other investors, which include Avid Technologies, the Centennial Fund, Asia Pacific Ventures, and Aweida Ventures.
"As the broadcast and professional television markets evolve towards digital television, [the Microsoft investment] further endorses Pluto's business strategy," Pluto chief executive Mark Gray said in a statement. "Microsoft is, and will continue to be, a significant influence in the world affecting the transition to future television systems."
Based in Boulder, Colorado, Pluto Technologies was founded in 1995. In April, the company announced that HBO Studio Productions in New York had purchased its "VideoSpace" digital video recorders.
According to Avid, the deal is valued at $285 million in cash and stock.