Google Inc.'s (GOOGL) YouTube unit said it acquired Directr, a mobile-video startup, to reach more small-business customers and boost its video-advertising efforts.

No purchase price was disclosed.

Directr has a mobile app for Apple Inc.'s iOS platform that makes it easy for small businesses to shoot, edit and upload short videos to the Internet. The Directr team will join YouTube's video ads team, Google said.

Directr now charges for its app, but it will be free once the startup joins YouTube, Google also said.