Nearly half (46 percent) of 18- to 25-year-olds spend as much time using online video services as they do watching TV, says RealNetworks.
Research by online video software firm revealed that just under a third (32 percent) say the PC is their preferred platform for watching TV and video.
However, when it comes to 36- to 45-year-olds, 20 percent watch at least 50 percent of TV programmes and movies via a PC.
"It's still early days for online video but as each year passes the quality and breadth of online video content increases dramatically and the tools to access, manage, share and consume the content grow ever more sophisticated," said Marili 't Hooft-Bolle from RealNetworks.
RealNetworks also said the research showed a demand for video on mobile devices, with 70 percent of Brits admitting there was at leats one occasion where they had wanted to watch video on their mobile but had not been able to.
Furthermore, just one in ten watch more than 10 minutes of mobile video per week. 31 percent admitted this was because they thought downloading video to mobile devices was expensive, while 13 percent thought it was too complex and would take too long.
"It's clear that the one-to-one, on demand online environment is taking over. Added to that, we now have video-capable mobile devices and pent up demand amongst their users," said Hooft-Bolle.
"Online video is already a compelling experience and with the right tools, mobile video can also be easy and affordable."