Agadtaiaakxheeq.mkv -

Right-click the file and select Properties (Windows) or Get Info (Mac). Sometimes the "Details" tab will contain the original title or tags.

Use a player like VLC Media Player or MPC-HC , which are designed to handle .mkv files regardless of their filename. AgADtAIAAkXhEEQ.mkv

If you found this in your device's "Telegram Documents" or "Telegram Video" folder, it is likely a video that was downloaded but not explicitly "saved to gallery/downloads" with its original name. Right-click the file and select Properties (Windows) or