Tokyo 2020 mascots, Miraitowa (L) and Someity (R) on stage during the Tokyo 2020 Olympic Games Two Years To Go Ceremony at Tokyo Skytree on July 24, 2018 in Tokyo, Japan.

NBCUniversal has received more than $1 billion in national advertising commitments for the 2020 Summer Olympics in Tokyo, the company said Tuesday.

On a conference call with reporters Tuesday, executives said this reflects double-digit growth over where it was pacing eight months before the Olympics in Rio de Janeiro, Brazil in 2016. Dan Lovinger, EVP of Advertising Sales for NBC Sports Group, said the company expects to surpass Rio's total of $1.2 billion in national ad sales. The Olympics will run between July 24 and August 9, 2020.

There's interest from new advertisers too, executives said, with more than half of advertisers committing being new to the summer games.

Next summer will be a hot one for media, with an approaching election and proximity to the Democratic National Convention and the Republican National Convention falling before and after opening and closing ceremonies, respectively.

A report from Interpublic Group of Cos.-owned media research group Magna released Monday said national TV ad sales declined by 3% in 2019 to $42 billion this year and will decline further in 2020 "even factoring the incremental ad revenues generated around the Summer Olympics." Meanwhile, digital media is expected to grow 11% in 2020, to reach 60% of total ad spend.

But NBC executives, who said more than 7,000 hours of coverage will be delivered from Tokyo, are thinking more about audiences than where they're watching. With so much of linear TV's audience decamping in favor of digital platforms, executives said the company has created a "single audience guarantee" for whether a viewer is watching via linear television or on a digital platform. The cost of ads range between $1 million and more than $100 million, they said.

Executives said this enables advertisers to "toggle back and forth" to take advantage of spikes in viewership — making so they're not really delineating between a linear viewer or a digital viewer, they said.

Since NBC exclusively owns the rights to distribute in the U.S. through 2032, executives said they're able to create partnerships with social platforms and distribute content in various formats depending on how viewers are consuming it. For instance, NBC and Twitter announced over the summer the social media platform will show limited live event coverage and shows.

The advent of digital video has not been kind to linear television, but Mark Marshall, President of Ad Sales and Partnerships, pointed out that events like this are the ones really pulling consumers to tune in.

"There's less and less big places where people gather; sports is one of those places where people absolutely do gather," he said. "Sports continue to bring large audiences together."

Disclosure: CNBC parent NBCUniversal owns NBC Sports and NBC Olympics. NBC Olympics is the U.S. broadcast rights holder to all Summer and Winter Games through the year 2032.