Files named 91.mp4 appear in various technical repositories and reports, such as a 29.1 MB video file associated with research entities like the University of Tennessee .

In computational chemistry, MP4 (fourth-order) is a method for calculating correlation energy. Scientific reports may note that it often covers approximately 91% of the full configuration interaction (FCI) correlation energy for certain electronic systems.

In the context of tools like yt-dlp or youtube-dl , is a legacy itag (format code) for a specific stream quality. Resolution: 144p. Video Codec: H.264 (MP4 container).

Often carries the lowest possible audio variant, such as HE-AAC at 48kbps .