In From the Cold S01E03 - The Widow (NetNaija.com).mp4

Video files are files that store digital video data on a computer system. Video is almost always stored using lossy compression to reduce the file size.

A video file normally consists of a container (e.g. MP4) containing video data in a video coding format (e.g. H.264) alongside audio data in an audio coding format (e.g. Opus). The container can also contain synchronization information, subtitles, and metadata such as title.