Michael Willner was the cable industry’s most popular CEO — and one of its most prominent representatives — up until February, when The Carlyle Group sold Insight Communications for $3B to Time Warner Cable. Now Willner and fellow Insight co-founder Sidney Knafel have paid an undisclosed amount for a controlling interest in Pittsburgh-based Penthera Partners. Willner be CEO and Knafel will be Penthera’s vice chairman. The software firm has developed a patented engine that moves HD video between Internet servers and digital devices including smartphones, tablets and IP-enabled set-top boxes. It’s also developing applications for cable companies. “Our transition to a new-media technology company, which is focused on next-generation consumer experiences, is the next logical step for us,” Willner says.