You can earn HOW MUCH playing video games?

If the concept of watching other people play video games seems stupid, then you might want to look at the salaries top e-sport gamers are commanding.

Carlos Rodriguez Santiago, or Ocelote as he is known in the e-sports world, was one of the top players and biggest brands ever. He started his championship-winning career at age 16. He has now retired at the grand old age of 24, after earning around 700,000 euros ($773,108) a year playing games.

The e-sport tournaments involve teams playing each other in popular fantasy titles such as "League of Legends" or "World of Warcraft," while avid fans around the world watch over the Internet. Twitch, the company Amazon bought for $970 million, is the most popular live game-streaming website. It said that in July more than 55 million unique visitors viewed more than 15 billion minutes of content, highlighting how engaged users are with e-sports.

"The good thing is that we have hit mainstream already. It is not just guys playing video games, it's about the ecosystem around the audience and content generation," said Sebastien Radu, managing director of ESL Spain, a company that organizes some of the world's biggest e-sports tournaments. In an interview with CNBC at Mobile World Congress in Barcelona, Radu said some players could also earn more than $1 million.

'Volatile'

So how are players making money?

The three main revenue streams for a player are sponsorships, prize money and salaries from the teams you belong to. Giant companies like Intel are invested and are sponsoring the Intel Extreme Masters World Championship in Poland next week, as the appeal of e-sports for advertisers continues to increase.

Prize money is also on the rise and ESL has committed a pool of $1 million across its five tournaments this year.

But it's not all glamour and big paychecks. Just like many sports, if you're not on top form, your income could be turbulent.

"As a player, it is a very volatile industry, it is not something reliable. As a player, maybe one year people love you at your peak, but then the next you're not so good," Santiago told CNBC.

Santiago's gaming alias Ocelote became a major brand. Just before he retired last month, the e-sports player started his own club. Club owners will bring players under their wing and form teams that they can send to tournaments. Santiago also said his players train eight to 12 hours a day.

The club owner is responsible for paying the players salaries and can even buy players from others clubs, -just like in soccer. There are even anti-poaching rules. To make money, clubs could take a cut of players' winnings and also earn sponsorship revenue.

Because of the major brand Ocelote is, Santiago said this allowed him to find the best players.

'Multibillion dollar business'

E-sports has become a lot more professional in its organization, Radu said, and as this continues, even average players will begin to earn big salaries.

"I do expect a leveling of that income and that is close to happening," Radu told CNBC.

"If you look at the average number, it is hugely higher than the previous years, maybe 200,000 euros a year on average. Before it was something like 10,000 euros per year about five years ago. There is huge growth here."

And as for the future? "We are not even close to reaching the top," Radu said.

"Right now we are just hitting mainstream, and the vision for the next the years is a multibillion dollar business."