"Public service media has a long and proud tradition in the UK. It delivers duly impartial and trusted news and original programmes which reflect British culture and bring the country together," a statement said.
"But the system is now under serious threat, with audience choice wider than it's ever been, broadcasters experiencing fundamental financial challenges and structural change in the advertising market.
"And in this environment, public service broadcasters are finding it much harder to fund the production and distribution of high-quality UK content to all audiences."
Ofcom has published a six-point plan, which also includes asking the government to consider additional funding for some genres such as news, local news and children's content.
It also announced a review of its regulation of broadcast TV and radio, because much of the current framework was designed for traditional TV.
Ofcom also asked for urgent clarity on whether digital terrestrial TV - which is transmitted using masts and ariels, and which currently supports Freeview - will be phased out after 2034.
A spokesperson for the Department for Culture, Media and Sport (DCMS) said: "We welcome Ofcom's Public Service Media Review and we will now consider its recommendations."
YouTube has been approached for comment.