If your default player won't open it, download the VLC Media Player —it's free and handles almost any codec.

Best for: Twitter/X, Reddit, or TikTok where the mystery of the filename creates curiosity. "If you know, you know. 📁 2022 071848858.mp4

To develop a "good post" for this, your strategy should depend on whether you are a funny/weird video or helping others figure out how to open it. Option 1: The "Viral/Mystery" Engagement Post