: Short for Blu-ray . This tells the user that the source of the video was a high-quality physical disc rather than a television broadcast (HDTV) or a web stream (WebRip).

: The file extension . MP4 is a universal container format compatible with almost all modern devices, from smartphones to smart TVs. Movie naming convention & format for best quality

: Indicates that the file includes subtitles . These are often "hardcoded" (burned into the image) or "muxed" (selectable) within the MP4 container.