THX is just an extension to already available surround sound and image formats.
It's supposed to replicate the way it was intended/made by the studio
Movies that bear the well-known logo have gone through the THX Digital Mastering Program. This is a professional services group that works with studios and post-production facilities to ensure that the highest standards are applied for sound, video, compression, and replication.
THX-certified video displays include a THX mode which allows users to see a program or movie as the creator intended