Google Inc has agreed to buy Seattle-based anti-piracy software firm Widevine in a bid to boost its online video services, the world's dominant Internet search company said on its official blog.

No price was disclosed, but the software firm has raised more than $65 million from investors including Cisco Systems, the Seattle Times reported on Friday.

Widevine's digital-rights management software is used by 250 million Web-connected TVs and other Web-connected devices to protect video content from unauthorized use, the Seattle Times said.

We're excited to welcome the Widevine team to Google, and together we'll work to improve access to great video content across the web, Google vice president Mario Queiroz said on the company's official blog.

Mountain View, Calif.-based Google's purchase of Widevine comes amid reports that Chicago-based Internet company Groupon Inc rejected Google's $5 billion to $6 billion takeover bid.

Groupon owners Eric Lefkofsky and Andrew Mason want to keep the fast-growing company independent and possibly pursue an initial public offering instead, the Chicago Tribune reported, citing two sources with direct knowledge of the situation.

Groupon, one of Chicago's fastest-growing companies, offers daily Internet deals from local businesses on everything from lobsters to massages. Google sought to buy the company to expand into local search advertising.

(Reporting by Ann Saphir, editing by Philip Barbara)