VIDEO_TS

On a DVD disc, DVD movie files are stored in the VIDEO_TS folder. There is also an AUDIO_TS folder, this is where DVD-Audio would be stored, but usually the folder is empty.

The TS stands for "title set" and is part of DVD structure. The before mentioned VIDEO_TS folder will hold all the pertinent information such as Informaton (IFO) and any backup (BUP) files that are necessary for the DVD to even be read.