If you have this file and need to verify its contents or origin, you can use several built-in and third-party tools to extract its Video Metadata : Information optics: How to view video metadata - Canto
: It typically utilizes the H.264 or H.265 codec for video, which allows for high quality at relatively small file sizes.
The file appears to be a specific multimedia container following the MPEG-4 Part 14 (MP4) standard. Based on standard file-naming conventions, "b5_148" likely refers to an internal project ID, batch number, or specific metadata tag rather than a widely known public viral video or standard software component. Technical Overview of the .mp4 Format
The MP4 format is a digital multimedia container used primarily to store video and audio, though it can also hold subtitles and still images.
: It is based on the "ISO base media file format" and uses a series of "atoms" or "boxes" (like ftyp , moov , and mdat ) to organize data.