Google is expected to unveil a search engine for Web-only video this summer that will let people preview media clips from its Web site, CNET has learned.

Google's planned service will let visitors find free short-form videos such as the popular "Star Wars" video spoofs, according to sources who asked to remain anonymous. The engine will complement the search giant's existing experimental site that lets people search the closed-caption text of television shows from PBS and CNN, among others, and preview accompanying still images. The new capabilities will let people watch roughly 10 seconds of Web video clips for free before shuttling visitors to the video's host site, sources say.

Sources said the new video search engine will be unveiled within the next two months.

A Google representative declined to comment on the details of the search engine or the exact timing of the launch but acknowledged that a new service is in the works. "All those details are still being worked out," the representative said.

Video search has become a highly competitive field for many Internet companies because it's seen as a valuable new market for online advertising. Google and Yahoo, for example, are looking to expand their multibillion-dollar advertising businesses into videos, which will help them land ad dollars from TV commercial advertisers. Even's search unit,, is eyeing the video search market, according to one source. A9 could not immediately be reached for comment.

Longer term, Google is preparing a payment system for a premium video service that would let people pay to watch full video clips. Google is talking to several top-tier content providers, including Hollywood movie studios, to gain agreements for aggregating their video and selling premium or pay-per-view access.

"The ultimate endgame is streaming video, otherwise Google can't get video advertising dollars," said one source. "They have to figure a way to get video into their world to capture those dollars."

The Mountain View, Calif.-based search giant outlined plans for a payment service when it launched its video-upload program in April. The program solicits video submissions to Google's searchable video archives, inviting small and major producers alike to submit work and grant copyrights to the company. Google said on its "frequently asked questions" page that it will let content producers host and sell access to their video using Google servers. It has yet to launch the service for public consumption.

The first stage of the video search engine will put Google on par with chief rival Yahoo, which finished work on its own Web video search engine in May, as well as others such as America Online's Singingfish and Blinkx. Unlike Yahoo, which already has submission deals with companies such as Reuters, Google will avoid mining the Internet for video clips and will use only video clips that have been submitted by their producers.