Roku -- the OTT platform of TV and streaming channels -- continues to see stock market gains, due to positive analysts' recommendations citing its smart TV deals and its own growing content channel.

Roku’s stock rose a big 7% in mid-day trading on Tuesday to $46.34. An Oppenheimer analyst touted the company’s own Roku Channel -- which is now adding meaningful viewership, which in turn could mean higher advertising revenue.

Media analyst Jason Helfstein says the channel is now the 12th-most-watched channel on Roku. Among other content, The Roku Channel runs free ad-supported movies.

“The Roku Channel allows them to play effectively as a content provider,” Helfstein tells CNBC. “Granted, we don’t see them making their own content like Netflix, but we see an opportunity to roll up a lot of the long-tail content.”

Helfstein says the key is content discovery: “Once you get out of top 12 applications of smart TV systems, it’s just too hard for people to find the content."

Roku consumers can choose from hundreds of free channels on Roku (set-top box or its integrated smart TV app) and thousands overall. Helfstein adds that the success of Roku could see a boost from Samsung TV sets that can now access the app.

Over the last three months, Roku’s stock is up 44% -- although still down 11% year-to-date.

Recently, Roku started Advertising Marketplace -- an effort to deliver targeted marketing for advertisers. AT&T’s WarnerMedia, which includes Turner networks, 21st Century Fox and Viacom, have signed on to sell advertising through Roku.

Last month, Paul Golding media analyst at Macquarie, touted Roku’s growing success in smart TV penetration to drive higher viewership and ad revenues.