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.
It is frequently used for live streams or by users with very low bandwidth to minimize data consumption. Other Contexts
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).
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 .