The TelemetryTV media player app may display a message on the screen that the platform is missing a service worker. 

A service worker is a process that runs within a web application.  It is responsible for all network communications and typically acts to cache network responses to ensure performance and offline capabilities.
​

TelemetryTV's media player is essentially a complex web application.  It is what is called a 'Progressive Web Application' (PWA).  Service workers are required as part of the specification for PWA's.   Within TelemetryTV it is responsible for providing offline support when the Internet is not available and also it caches the media files so they're not repeatedly downloaded wasting bandwidth which would be a huge issue for video content especially.

ChromeOS version 64 had a major bug which prevented Service Workers from working at all.  You must upgrade your ChromeOS platform to version 65 or higher.  We suggest always keeping ChromeOS up to date with patches for security and compatibility reasons.  TelemetryTV only tests and supports the current release version of ChromeOS.

Other web platforms may not implement service workers at all.  Please ensure that your platform has support for PWA's and service workers.  TelemertyTV is not supported on platforms without service workers.

If you're running a desktop browser and you have an adblocker installed it's possible that it is incorrectly filtering out the workbox library provided by Google that is used by TelemetryTV for service workers.   Please disable your ad blocker.