DVD:  Filesystem layout
VIDEO_TS/
      VIDEO_TS.IFO     VMGI file (Video Manager Information)
      VIDEO_TS.VOB    VOB file for the VMG menu (if any)
      VIDEO_TS.BUP    Backup copy of the VMGI file

      VTS_01_0.IFO     VTSI file (Video Title Set Information)
      VTS_01_0.VOB    VOB for the VTS menu (if any)
      VTS_01_1.VOB    First Tile VOBS file
      VTS_01_2.VOB

      VTS_01_1.BUP    Backup copy of the VTSI file
      VTS_02_0.IFO     VTSI file for the second title
      VTS_02_1.VOB

      VTS_02_0.BUP