The AUDIO_TS folder is always empty, but some players still demand to see it if the disk is to play properly. The VOB files are muxed; ie: the video & audio are combined together. The VOB file will contain as many audio tracks as it may use, be that different languages or dolby & pcm & DTS. eg: if you demuxed VTS_01_2.VOB, then you would get an mpeg 2 video file, ac3 file(s), & DTS file(s), etc.