If a video file claims you need to download a specific "special codec" or "player" to view it, it is almost certainly a virus.
Historically, files labeled with enticing or generic adult titles have been used to spread Trojans, keyloggers, or ransomware. Douga de ecchi.mp4
Ensure the file ends strictly in .mp4 , .mkv , or .mov and does not have a hidden .exe or .scr suffix. If a video file claims you need to
A slang term for suggestive, playful, or erotic content. mp4: A standard digital multimedia container format. Douga de ecchi.mp4
Sometimes a file may appear as Douga de ecchi.mp4.exe . If the user has "Hide extensions for known file types" enabled in Windows, they may only see the .mp4 part and accidentally execute a program instead of playing a video.