Spanish broadcaster Antena 3 delivered 2m sponsored links to its viewers in four days after its ‘audio watermarking’ app was downloaded by 200,000 users.

The app, called ANT 3.0, recognises hidden digital audio codes played during TV broadcasts and links to relevant online content.

It is available on iPad, iPhone and Android with downloads split roughly 50-50 between iOS and Android.

Antena 3 launched the app with its live talk show ‘El Hormigeuro’, linking viewers to photos, Facebook pages, trailers and songs on Spotify.

This video, though in Spanish, gives an idea of the functionality.

The campaign was sponsored by Movistar so all the linked content had the phone company’s branding on it.

The technology behind the app is supplied by Cambridge-based Intrasonics which has been using audio watermarking for several years to measure radio audiences for Ipsos Mori.

Intrasonics CEO Luc Jonker said the company was now looking to sell the white label technology to commercial companies.

It can link to literally anything, such as competitions, social media, or additional content. The only limit is the creativity of the broadcaster.

He said it could be used to run loyalty schemes, offer rewards or simply to drive engagement.

Smartphones are increasingly becoming the first screen in our living rooms rather than the second screen, so we are offering broadcasters a way of making sure viewers stay engaged with what is happening on TV.

Following its initial success Antena 3 plans to integrate the app into forthcoming cookery shows and F1 coverage.

In the UK Channel 4 has also used the technology to add an additional layer of content to its new Facejacker series – a follow on from its Fonejacker app that achieved 440,000 downloads.

Two digital watermarks are hidden in each episode that give access to unseen clips, ringtones and other bonus features.

While Channel 4 is charging £1.49 for the app, the real opportunity seems to be with free apps funded by sponsorship.

The Facejacker app only works with that particular show, while the Antena 3 app can be synced with any of its broadcasts, even with live shows in real time.

Jonker said that during the ad break of El Hormigeuro a popstar guest on the show sang an impromptu opera song for the audience, and in the second half of the show Antena 3 embedded it as bonus content through ANT 3.0.

One functional issue that needs to be solved with the iOS version of the app is that you can’t run it in the background while performing other tasks, so the smartphone or tablet is out of action for anything else while the app is running.

The Android version can run in the background allowing the viewer to use their phone as normal and Jonker said the company is working to bring this functionality to iOS.