Most likely recorded on an iPhone or iPad . When you transfer a video from an iOS device to a computer via a direct cable or certain cloud services, the device often renames the file from a generic label (like IMG_1234 ) to this precise timestamp.
Can be opened using the Movies & TV app, VLC Media Player , or by installing the HEVC Video Extensions if the video was recorded in High Efficiency mode. 2021-10-21 16.45.43.mov
The name follows a chronological format that tells you exactly when the recording started: October 21, 2021 Time: 4:45 PM (and 43 seconds) Format: .mov (Apple’s QuickTime File Format) 2. File Characteristics Most likely recorded on an iPhone or iPad