A is a digital copy of a movie or TV show where the video and audio streams are taken directly from the physical disc (Blu-ray or UHD Blu-ray) without any re-encoding.
The data on a commercial Blu-ray is structured in a complex way (usually in a BDMV folder structure with .m2ts files). To make the file easier to play on computers and media servers (like Plex or Kodi), the content is "remultiplexed" into a container. This changes the "packaging" but does not change the contents inside. remux torrent