In AR development (using platforms like Kivicube or AR Code ), MP4 files are used as "AR Videos" that overlay digital content onto the real world. The "00103b" would be a specific version or asset ID in a developer's library.
Most AR platforms recommend avoiding full-frame pure black at the start to prevent "blank" triggers. How to Manage the File AR 00103b mp4
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. In AR development (using platforms like Kivicube or