dlna-cat is a cross-platform command-line tool that casts screen and media file to remote DLNA device.

dlna-cast uses ffmpeg to capture screen and audio, then convert them into HLS streams which could be served by a simple HTTP server. The HLS url will be send to the selected device via uPnP protocol and then you can watch you screen on the remote device (smart TV, typically).

This tool is supposed to be cross-platform but currently I don't have a Linux or MacOS device at hand so it can only run on Windows now. It won't be hard to support other platforms though, as there are no platform specific dependencies.

HLS is chosen just because it is easy to implement. But the problem of HLS is its high latency (up to 5-10s or more) so it's definitely not for scenarios that require low latency (presentation for example). But as a trade-off the streaming quality exceeds a lot of software screen-casting solutions (Lebocast for example) that have been tested by myself, which make it pretty good to stream music or video playing from your PC to TV.