The first "truly multiplatform" Olympic Games contributed a 2.9 million digital audience for Australian rights holder Seven West Media.

Research from Roy Morgan shows three in four Australians aged 14+ tuned in to watch the 2016 Rio Olympics, a total of 14,778,000.

And while free-to-air TV across four channels still delivered 94 of the total audience, the investment in digital channels "clearly paid off" by increasing engagement among many viewers, the researcher's Michele Levine says. Of Seven's digital platforms, 1.73 million streamed coverage directly through the Olympics on 7 website or app - with 1.24 million and 829,000 users respectively - and 1.57 million engaged with Seven's Olympics content through its social media accounts on Facebook, Twitter and Instagram.

Another 1.4 million Aussies caught up on some Olympics highlights via YouTube, including the 7Olympics channel.

"This is the first Olympic Games operating in a truly multiplatform environment," says Levine. "But all the noise around clicks, streams and views overlooks measuring just how many people used one or several platforms to watch the events, and therefore how many people tuned in.

"The digital platforms added many different ways for Australians to engage with the Olympics. Not only did digital extend Seven's TV audience by an additional 821,000 Australians 14 and over, but 2.1 million TV viewers (16 per cent of them) boosted their engagement with Seven's Olympics content via web, app, and social media.

"The next step in this cross platform research is our new digital audience system Roy Morgan Audiences. This brings together Single Source and Helix Personas data with a panel of over 19 million internet connected devices. The scale of the panel provides a means for broadcasters and advertisers to measure and profile all their cross-platform digital activity to determine true multi-media reach of their valuable content."

Pictured: Who watched what - figures for the number of Australians aged 14+