At one time, it was taken for granted in China that music and video content would be shamelessly pirated online. But a new lawsuit suggests the country may have to get serious about enforcing its copyright laws.

A group of Chinese companies including video hosting services Youku Tudou, Sohu, and Tencent's v.qq.com, have teamed up on a $48.9 million lawsuit against Baidu, the dominant search engine in China.

Baidu feeds content into its own web and mobile video services, the plaintiffs argue, which include Baidu Yingyin, Baidu Video App, and Baidu TV Stick. The video search also leads users to places where they can download pirated material.

Chinese online video companies have begun licensing content and even producing original content in recent years, but they claim that new business is threatened by piracy.

"We cannot keep competing because where thieves and robbers are having their way, law-abiding companies cannot survive," Sohu chairman Charles Zhang reportedly said at a press event.

Baidu has made attempts to control piracy in the past, blocking videos and paying licensing fees to music copyright holders.

This lawsuit may signal a new era in Chinese copyright enforcement, however. Lawyers told The Wall Street Journal that more lawsuits are on the way.

Correction: An earlier version of this story said that the plaintiffs had been joined by the Motion Picture Association of America. While the MPAA supports the suit and attended the announcement, it is not a plaintiff in the case.