While the XviD codec has since been superseded by superior formats like H.264, H.265 (HEVC), and AV1, these legacy file tags remain historical markers of the internet's formative media-sharing culture.
An open-source MPEG-4 video codec that dominated the 2000s. It allowed large video files (like DVDs) to be compressed into roughly 700 megabytes (the capacity of a standard CD-R) while maintaining acceptable visual quality.