Right-click the file and select Properties (Windows) or Get Info (Mac). If the size is 0 bytes or very small (e.g., 1KB), the download failed or the file is a shortcut.
The "Swiss Army Knife" of video. It can play almost any .mp4 even if the file is slightly corrupted. 7711_720p.mp4
A lightweight alternative for Windows users. Right-click the file and select Properties (Windows) or
Some DVR systems name files by camera number or timestamp segments. 7711_720p.mp4