Live streaming is booming. People spent 1.2 billion hours watching Twitch in the first quarter of 2020, according to analytics company StreamHatchet and streaming software company Streamlabs. Time spent viewing the live-streaming service, a unit of Amazon, jumped 23 percent from February to March, and the number of unique Twitch channels increased 33 percent over the previous quarter. Other live streaming platforms like YouTube, Facebook, and Microsoft’s Mixer also saw more use.

It’s not just video games. People host live cooking shows. Musicians are live streaming concerts. Programmers use Twitch streams as a way to swap tips.

“I think it’s a great time to try streaming,” says Justin Turner, a digital marketer in Portland, Oregon, who just started a new live streaming talk show about Dungeons and Dragons and other tabletop games. “It’s a great way to interact with people. Just knowing some of my friends are watching and chatting really helps with social distancing.”

Like many other streamers, Turner uses a video streaming and recording application called Open Broadcaster Software Studio, which unlike commercial options like Camtasia, is free and open source.

Twitch offers its own free streaming software that’s easier for beginners, but OBS Studio users say they prefer the app for its advanced features and how much it can be customized. “It’s still relatively easy to use but there’s a lot of tinkering you can do if you’re into that sort of thing,” says Turner.

The app is also useful for people who don’t live stream. Bastian Bechtold teaches computer science at Jade University in Germany, and like many teachers around the world, is producing video lessons for his students. He turned to OBS Studio to record lessons because the app makes it easy to hide and unhide parts of his screen, which enables him to show students a problem and then unveil the solution without doing any video editing, saving time. “I came into this not knowing what was possible, and OBS works really well,” he says. “Even a complex setup was fairly straightforward to create.”

OBS Studio creator Hugh “Jim” Bailey estimates that the software is probably used by tens of millions of people, based on the number who download updates. The pandemic has likely doubled interest in the tool, Bailey says, with about 320,000 unique visitors a day now coming to the OBS Studio website. That’s not counting variants of OBS Studio like Streamlabs OBS, which is based on the original project’s code but developed separately. Streaming platforms Twitch, Facebook, and YouTube include links to OBS Studio in their resources for live streamers.

Bailey created OBS Studio in 2012 after years trying to break into the video game development industry to no avail. “It didn’t work out,” he says. “The industry is way too competitive and brutal. I was 30 years old and living with my father, and needed to try something new.”

Bailey was a fan of Starcraft and loved watching people play the game on Twitch. He wanted to start his own Starcraft live stream, but couldn’t find any free and open source live streaming tools. “I was the sort of person who would build his own tools just for fun,” he says. “I thought it was a cool opportunity to do open source for the first time because I really loved open source software.”

Bailey developed a prototype of OBS Studio and posted it to Reddit and a Starcraft forum. Soon other programmers were pitching in to help develop the software.