: Short for Blu-ray , indicating the high-definition disc source the video was ripped from.
In short, it is a high-definition Blu-ray rip of The Little Mermaid with subtitles included. 10745-BR720p-SUBS-THELITTLEMERMAID.mp4
That file name is a standard string used in digital media to describe exactly what the video file contains. : Short for Blu-ray , indicating the high-definition