These are high-quality files extracted directly from physical Blu-ray discs. A "Remux" contains the exact video and audio data from the disc without loss of quality, while a "BD Rip" is usually compressed to a smaller file size while maintaining high-definition (720p or 1080p).
This is the dealbreaker for home theater owners (soundbars or surround sound systems). Streaming services use compressed Dolby Digital Plus (DD+). BD torrents contain or DTS-HD Master Audio . bd torrents