The BBC has released a public beta of its own software application for watching video online, hoping to engage younger people who are consuming more and more of their content over the Internet.

Other British broadcasters have released video players, but the BBC -- which has been trying to transform itself amid falling viewer numbers -- hopes to attract users by making its vast programming archives available globally.

Called the iPlayer, the software lets people search for and download BBC programs and then watch them later within a certain time limit, a concept called on-demand viewing. Later, the BBC will allow people to watched streamed programs in real time as they are shown on television.

The service won't just be for the U.K. BBC Worldwide, the BBC's commercial branch, hopes to launch a commercial version of the iPlayer next year in the U.S. and Australia. Overseas users will have to pay to watch ad-free BBC content, or choose to view content with advertisements for free.

"We obviously want to replicate the service around the world because there's a huge following for BBC content," a BBC spokeswoman said Friday. "It makes sense for us to focus on English-speaking countries first."

As structured now, the iPlayer lets U.K. residents watch some programs that aired during the previous week for free and without advertising. After users download a program, they have 30 days to watch it before the program deletes itself. Once users begin watching a program, they can start and stop it or watch as many times as they want for a week before the program deletes itself.

The iPlayer presently works only with Microsoft's Windows XP OS, which has ignited criticisms that the BBC spent taxpayer money to support just a single vendor and a certain number of users. Users must also have Microsoft Windows Media Player version 10 or later.

The Open Source Consortium, an 80-member group dedicated to open-source software, has complained to British regulators as well as the BBC Trust over the iPlayer's OS limitations, saying it excludes about 25 percent of computer users.

But the BBC plans to release a version for Apple's OS as well as Microsoft's Vista by the end of this year. A BBC spokeswoman was unsure if a Linux version is planned, but "basically we want to ensure it is available on all platforms," she said. "We started with Microsoft because it opens it up to the biggest audience."

The BBC also wants to eventually create a version for mobile phones and other platforms, part of the broadcaster's "Creative Future" strategy to expand how it distributes content.

About 15,000 users participated in a closed beta for the iPlayer that ended Friday. The BBC said it will allow a gradual increase in the number of public beta testers over the next few months, with a full launch of the iPlayer later this year.

The BBC has set up an automated workflow that aims to quickly repurpose programs for the iPlayer. Red Bee Media, a digital media technology company, adds metadata to programs to make it easier for users to find them through searches, as well as transcoding the programs and ensuring their quality.

Siemens is in charge of the technical infrastructure, such as applying the digital rights licenses. The BBC is also using VeriSign's Kontiki Broadband Delivery Service software, which uses P-to-P (peer-to-peer) technology to download and distribute video.