SAN FRANCISCO — YouTube is being reprogrammed for the iPhone and iPad amid the latest fallout from the growing hostility between Google and Apple.

The changes are being made because Google and Apple didn’t renew a five-year licensing agreement that established YouTube’s video service as one of the built-in applications in the operating system that runs the iPhone and iPad.

YouTube is being bumped from the menu of pre-installed apps on the next version of Apple’s mobile operating system, or iOS, which could be released as early as Wednesday when the latest iPhone is expected to be unveiled.

Google is making a preemptive strike today with the release of a revamped YouTube application. The app is designed to make it as easy as possible for the tens of millions of iPhone and iPad owners to continue watching clips from the world’s most popular video site.

The new YouTube app will create more moneymaking opportunities for Google and video producers because it allows advertising to be shown with the clips. That’s something Apple hasn’t allowed on the pre-installed YouTube app. The ban on ads prevented many music videos and other widely watched clips from being shown in the iOS app.

Removing the advertising limitations will mean users of the new iOS app can watch YouTube videos that already have been available on smartphones running on Google’s Android software said, Francisco Varela, YouTube’s global director of platform partnerships.