The "AR" prefix often refers to Advanced Recording Format (.arf) used by Cisco Webex. Since yours is an MP4 , it has likely already been converted from its original meeting format to be playable on standard devices.
Most AR platforms recommend avoiding full-frame pure black at the start to prevent "blank" triggers. How to Manage the File AR 00103b mp4
Based on technical standards for files with these identifiers, Likely Contexts The "AR" prefix often refers to Advanced Recording Format (
Many security systems and dashcams use sequential alphanumeric naming (like AR 00101, AR 00102) for exported MP4 clips. Technical Specifications for "AR" MP4s How to Manage the File Based on technical
If you have an original .arf version of this file that won't play, you can use the Webex Recording Converter to turn it into a standard MP4.
If you are trying to create an AR experience with this file, tools like Adobe Express can help ensure the MP4 is optimized for web-based AR triggers.
If it is a standard MP4, it should open in VLC, Windows Media Player, or QuickTime.