Google has started integrating items from YouTube into its video search results as it starts to build a comprehensive video search and content platform. 

The search giant previously offered only videos uploaded by users to Google Video, which was launched in January 2006. Google acquired YouTube last October for $1.65bn.  

Google confirmed that its video search will expand further beyond content uploaded directly to its servers.

"Today is the first step in our plan to bring you a comprehensive video search and content platform. We will provide ongoing updates as they unfold," wrote Salar Kamangar, vice president of product marketing at Google, on a company blog. 

Building a video search engine is challenging because movies cannot be indexed and ranked in the same way as traditional web content, as video files do not currently contain any data that informs search robots of its contents.

Hosting the videos directly allows Google to more accurately determine the topic and popularity of an item.

Yahoo video search currently includes results from both its own video service and third-party websites and video services including Blip.tv and YouTube. 

Many publishers choose not to upload video content to YouTube-like services as it does not allow them to monetise the traffic through in-video advertising and banner ads.

Instead they opt to host the video on their own servers, where it is often not indexed by search engines.