A smart TV operating system is the software that runs a smart TV or a streaming stick. It shows the home screen, installs and runs the apps, connects to Wi-Fi and responds to the remote. It plays the same role on a TV that Android or iOS plays on a phone. Most TV brands do not write their own. They license an operating system from a software company.
Why would a TV brand license its software? Building an operating system takes hundreds of engineers. More importantly, viewers buy a smart TV to use streaming apps. Each streaming service must build and test a separate app for every operating system, as the page on streaming apps for smart TVs explains. So services build apps first for the operating systems that already have many viewers. A TV brand that wrote its own software would struggle to get those apps.
The company that makes the operating system earns money in an unusual way. It often charges TV brands very little, or nothing, for a licence. It earns instead from the viewers, after the TV is sold. Its main income is ads on the home screen, such as a large banner for a new series. It also takes a share of the subscriptions that viewers buy through the TV, and fees from services that want their app placed in the first row. These home-screen ads are sold through connected TV (CTV) advertising.
For instance, a family in Indore buys a 43-inch smart TV for ₹24,000 during a festival sale. When they switch it on, the operating system asks them to sign in and pick a language. The home screen shows a row of streaming apps and a banner for a new Hindi thriller. Below the apps sits a row of free channels, such as news, devotional songs and old films. The family's son subscribes to a streaming service from the TV, paying ₹149 a month. Part of each payment goes to the operating system's maker.
Those free channels are called FAST channels. They play a fixed schedule like television, over the internet, and are paid for by ads. Many are run by cloud playout software. Some operating system makers run their own FAST services, especially in the United States, where such services are now large.
The operating system also decides what the TV can show. It supports the picture and sound formats that the TV hardware can play, such as HDR, a format for brighter, more detailed pictures. The page on immersive audio and HDR formats explains these. How is a smart TV operating system different from a streaming service? The operating system runs the TV and every app on it. A streaming service is one of those apps.