At this year's E3 event, the generous showroom space historically occupied by Microsoft Corp.'s Xbox was allocated entirely to the company's Mixer game-streaming platform. The company, meanwhile, transformed an adjacent building that it owns into a dedicated area for all things Xbox.

The expanded real estate on the annual video game conference floor comes a few days after Microsoft announced that its Mixer service, which allows gamers on Windows 10 PCs and Xbox consoles to broadcast the games they are playing to audiences, doubled its viewership in the last six months to hit the 20 million mark. While still a far cry from Amazon.com Inc.'s Twitch that continues to dominate the video game-streaming market with about 100 million active monthly users, Microsoft expects Mixer's steady growth to continue as it offers certain features that are not available on competitors' platforms.

The most prominent of those features is "MixPlay," the effects of which were on display at E3. As streamers played and broadcast their games from within the pods, various lights within the structure continued to change colors.

"MixPlay is our brand of interactive experiences that gives streamers the ability to allow their audiences to take control of or influence the games that are being played," Jenny McCoy, director of Mixer marketing, told S&P Global Market Intelligence. "Audiences are actually changing the colors live from their homes right now. They can also use MixPlay to add other sound and video effects, giving the entire experience a level of interactivity to what is essentially a passive experience on other platforms."

Aside from adding physical effects, certain games also allow MixPlay to influence the gameplay itself. As an example, McCoy cited Microsoft's largely popular "Minecraft," whose developers worked with Mixer to create features that allow audiences to insert content such as items and monsters within the game world.

Another feature unique to Mixer is "HypeZone." McCoy explained that the feature uses machine learning and computer vision techniques to automatically follow a player streaming a game. If the player dies, HypeZone automatically shifts to the perspective of another player streaming within the same game. The smart perspective switching feature allows audiences to continue following a match without having to constantly switch between different streams of different players.

"This is especially useful for Battle Royale-style games, such as 'Fortnite' and 'PlayerUnknownBattlegrounds,' that are by far the most-streamed games on Mixer at the moment," McCoy said.

Microsoft also expanded its streaming partnership with developer Hi-Rez Studios for its freshly-launched game "Realm Royale." The company hosted a tournament in the booth that was being broadcast live on Mixer and the winner had the option to choose their video game console of choice. The strategy seemed to be paying off as a steady stream of people continued to shuffle into the booth, which also happened to be in the same vicinity as the area Amazon had designated for Twitch.

While a number of competitors, including Google Inc.'s YouTube Gaming, have launched to challenge Twitch over the past few years, none have been able to make a dent in its ever-growing viewer base so far, largely due to Amazon's exclusive streaming deals with popular games and esports organizations, such as Activision Blizzard Inc.'s Overwatch League.

McCoy said Mixer does not have any new deals to announce on the esports front yet. Instead, Microsoft is betting on the uniqueness of MixPlay to expand its viewer base.

"Right now, I think we're barely scratching the surface of what MixPlay is capable of," McCoy said. "I think we're going to be seeing more developers and streamers coming up with new ideas."

Additional E3 2018 coverage:

Sony sticks to games, stays silent on VR, streaming

Microsoft boosts gaming with new acquisitions, streaming initiatives

Nintendo's new Switch titles draw massive crowds