Security footage often stops abruptly, which can "break" the file. Use VLC's "Repair AVI Index" feature when prompted upon opening.
Sites like Zamzar or CloudConvert can handle individual files without software installation. 4. Technical Troubleshooting 2018-08-26 20 49 39-P.avi
The "gold standard" for security footage. It includes its own codecs and can often repair broken indices in older files. Security footage often stops abruptly, which can "break"