From the time its first video was uploaded in 2005, YouTube has been known as the place where people can watch an endless stream of weird, funny, interesting, breathtaking or sometimes even mundane video clips  — all for free.

But over the past year, the Google-owned property has been gradually moving to emphasize higher-quality content, formal "channels" and increasingly sophisticated advertising.

Now comes a report in Advertising Age that YouTube is preparing to launch its first paid subscriptions for a limited number of individual channels, perhaps in the next few months.

The report, which cites unnamed "people familiar with the plans," says YouTube has invited some video producers to submit plans for creating channels that users would pay to watch. The report says the program would be an experiment to see how viewers respond. And according to Ad Age, YouTube is also considering charging for access to certain content libraries and live events.

YouTube chief Salar Kamangar has previously said the company was considering offering subscription-based video, but nothing definite has been announced. In an e-mail statement Tuesday, a company spokesman didn't confirm the Ad Age report but didn't rule it out, either.

"We have long maintained that different content requires different types of payment models," the statement said. "The important thing is that, regardless of the model, our creators succeed on the platform. There are a lot of our content creators that think they would benefit from subscriptions, so we're looking at that."