Since .mkv is a flexible container, VLC is the most reliable tool to play it regardless of the internal codecs.

Many security systems use ISO 8601 timestamps to organize archives for easy searching by time and date.

If you are looking to recover or analyze the content of this specific file, you should:

OBS Studio defaults to this naming convention ( YYYY-MM-DD HH-MM-SS.mkv ). This specific file would represent a session recorded in the early morning hours of August 7, 2021.

Are you trying to from this date, or did you find this file in a specific archive or community folder ?

The filename appears to be a default timestamp-based name typically generated by recording software like OBS Studio , ShadowPlay , or security camera systems .

Files shared on these platforms often retain their original system-generated filenames if they aren't renamed by the uploader. How to "Develop" the Content