Google has warned users of its Google Video service that their content will be obliterated after May 13, as the company formally shifts its multimedia focus to YouTube.

The Google Video service hasn’t allowed video uploads since May of 2009, and content on the video sharing service will be unavailable for playback as of April 29, according to a letter sent to users. However, users can download their content now and keep it on their own machines or transfer it to YouTube (though the YouTube transfer is not automatic).

An estimated 2.8 million videos are hosted on Google Video, according to one blog.

Google launched the service in January 2005, but not long after Google bought YouTube for $1.65 billion in 2006 the company began transitioning Google Video into a broad video search engine. And in its letter to Google Video users about the elimination of  their content, Google said “We've always maintained that the strength of Google Video is its ability to let people search videos from across the web, regardless of where those videos are hosted. And this move will enable us to focus on developing these technologies further to the benefit of searchers worldwide.”

A petition is circulating online by some die-hards who are pushing Google to preserve their Google Video content. Others lamenting the demise of Google Video include the Independent Film Channel, which offers its guide to films to watch on the service before it goes away. 

Meanwhile, Google continues to evolve YouTube through internal efforts and buyouts. YouTube last month bought a company called Next New Networks in an effort to offer video content producers more advanced tools and earlier this year partnered with LG Electronics to make it easier for users to capture 3D images and video on their mobile phones and transfer it to the Internet.