1_(2).mp4

: The standard file extension for digital video content.

If you'd like to identify a specific video you found, could you describe or what happens in the video ? 1_(2).mp4

Because this is a placeholder name, the "content" could be anything from a personal video recording to a downloaded social media clip or an automated export from video editing software. To find out what is actually inside the file, you can try: : The standard file extension for digital video content