If you found this in a temporary folder, it may be a cached version of a video you previously viewed on a social media platform. How to View or Identify the Content
The naming convention, particularly the addition of (1) , often occurs when you download the same file multiple times to your device, with your computer or phone automatically numbering the copies. 770054949544_3(1).mp4
If the file won't open in your default player, the VLC Media Player is a reliable, free tool that can handle almost any MP4 codec. If you found this in a temporary folder,