: 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
: This is typically a unique release number or a project identifier assigned by the group that encoded the video. 13742-BR1080p-SUBS-UNDERWRAPS.mp4
: Indicates that the file includes subtitles . These are often "hardcoded" (burned into the image) or "muxed" (selectable) within the MP4 container. : The file extension