: Open the file with VLC Media Player or Handbrake to see the video metadata and codec information.
: Many security systems name files using a sequential numerical string followed by the format. 23775mp4
If you found this code in a folder or online, it is almost certainly an . : Open the file with VLC Media Player
: If this was a download, check the "Downloads" history in your browser to see which website it originated from. 23775mp4