Android TV is a forked version of Google’s open-source Android operating system made for smart televisions. There are two types of Android smart TV versions you can purchase: AOSP-based and Android TV OS based. AOSP based Smart TVs come preloaded with Google’s open-source Android OS, the version used on mobile phones and tablets.
Certified Android TVs use a proprietary forked version of Android developed by Google to operate smoothly on TVs. This also means the apps you download on it via the Play Store are fully optimised to be used on televisions. Due to this being a perfect fork, it also comes with a number of other features like Chromecast.
All issues and bugs with Certified Android TVs are taken care off by Google, which means that the operating system is comparatively more stable to the AOSP version. It also has comparatively better performance as it is specifically made to run on low specification chipsets found in TVs.
Certified Android TVs are the way Google wants people to experience Android TV, similar to stock Android or Android One devices. However, these do cost a bit more than the AOSP-based versions.
AOSP-based TVs use the open-source Android operating system, but often without any authorisation from Google. This means that some of these devices might also not support some Google services like the Play Store.
So Certified Android TV is any day a better bet than an AOSP-based version.
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