If you look at the files on a DVD, you will notice that most DVDs have both a VIDEO_TS and AUDIO_TS folder, but the AUDIO_TS folder is usually empty. DVD-Audio would be stored in an AUDIO_TS folder but is a separate format to DVD-Video.
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.
The empty AUDIO_TS folder is normally required for the disc to be recognized as a working DVD.
