If you saw this on a platform like Reddit, Twitter (X), or a forum, it is likely a specific that the uploader didn't rename. One specific older reference to a "vid_791" file appears in automotive performance forums like Pro-Touring.com , where it was used to demonstrate LS3 engine dyno results showing power gains from specific cylinder heads and camshaft setups.

The "vid_###.mp4" naming convention is typically a default file name generated by:

: Often used when a user re-uploads a video they've saved.

: Devices often use sequential numbering for video files.

To help me identify it, could you describe or where you saw it posted ?