>>771626A while back, they started showing what game a person was playing when it's opened and Discord is open, too. You can do this with any program if you specify it. Then a few months ago, they added the function to stream it to anyone in the same channel as you. In the picture I posted, I specified it to watch for MPV, so whenever I open MPV, I can stream it to people in the channel. The share button is on the right.
Note that the connection depends on your internet and other peoples' internet. So, if you've got shit internet or they have shit internet, the stream will suck. Also, if you don't have Nitro, you get less streaming options.
Actually, I'll just link a video that probably explains this all better:
https://www.youtube.com/watch?v=SwdA96JTHAoJust do what he mentions in the video when he says "If it doesn't detect your game..." and replace it with your video player.