Linux – Is it possible to push multimedia content on DLNA TV from Linux

This is an old question (from 2011), and there's still no reasonable way of doing this. DLNA is not intended for live content mirroring. Its just the wrong tool for the job.

The best way to achieve screen mirroring/extension to televisions in 2016/2017 is to use a Miracast receiver (built-in to most 'smart' TVs these days, or something like the Microsoft Wireless Display Adapter) with Windows 10's 'project to display' functionality or use a Google (Chrome)Cast to mirror Chrome or your desktop.

Most of the time when I run into that... it's because the codec used to encode the video isn't compatible with the player. Just because the computer can play it... doesn't mean the TV knows how to decode it.