What app can I use to airplay a video file from FILES to my Smart TV?

I might be super dumb. When I load it up in the native video player, I don't see the Airplay button. I've tried on VLC but it only airplays audio, unless I do the Screen Mirroring thing first but then it's laggy. I've tried nplayer but same thing, just audio. I tried Infuse but they want me to pay for Pro. I'm super confused why Safari can airplay almost any streaming website, but when I have a video file on my device itself, I can't easy airplay it.