(AP Photo/Marcio Jose Sanchez, File)

Google's dominance of the online search market has often put it at odds with copyright holders, who argue the company should hide results likely to contain pirated content. On Friday, the search engine giant announced new efforts in response to that concern, saying that it would do more to reduce the visibility of pirated content in search products -- including testing a new ad format and tweaking its autocomplete search feature.

According to Google, the company received more than 224 million requests last year to remove search results under the Digital Millennium Copyright Act -- and ultimately removed 222 million of them. The average turnaround for copyright notices was less than six hours last year, the company says.

One of Google's strategies for fighting online piracy is to promote legal ways to access content. On that front, the company says it is testing a new ad format that pops up in search results for music and movies. When users search for such content using words such as "download," free or "watch, for example, Google's search results will automatically direct them to legitimate content sources, such as Amazon, Netflix or its own Google Play store, in a prominent position at the top of the page. The search engine is also trying out a right-hand panel in search results for the same kind of listing. The tests are only being run in the United States right now, but the blog post suggests an international rollout may be in the cards down the line.

In 2012, the search giant announced it would track the number of valid copyright removal notices that Web sites receive and potentially use that to limit where repeat offenders appear in search results. Now the company says it has refined that process in ways that could "visibly affect" the rankings of most notorious piracy sites. That change will be rolled out globally this week, Google said.

Google is also removing more terms related to copyright infringement from its autocomplete feature, which predicts search queries as users type, and is "demoting" autocomplete predictions that return results featuring sites with lots of DMCA complaints.

Google has long filtered some words associated with online piracy, saying in a 2010 blog post that it was committed to "prevent terms that are closely associated with piracy" from being suggested by autocomplete. The company eventually started filtering even the names of popular file sharing Web sites from autocomplete results -- cutting Google searches related to popular torrent download site the Pirate Bay in half in a matter of months, according to a 2012 report from TorrentFreak.

Senate Judiciary Committee Chairman Sen. Patrick Leahy (D-Vt.) praised Google's efforts in a statement Friday. "All businesses in the Internet ecosystem have an important role to play in minimizing illegal activity," he wrote. "I commend Google for recognizing that responsibility and announcing that it will take these promising steps."