You don’t provide enough clues about your workflow, but the video_ts and audio_ts folders (both are required even though audio_ts is always empty) are created by the program that “prepares” your DVD files.
My workflow is to make he mpeg/ac3 files in Vegas, then move them into DVDA to author the DVD menus. When I select “Prepare” in DVDA, the program makes the _ts folders. I use DVDA to burn the discs, but you can use any DVD burning software at this point.
In DVDA you are prompted to provide a path to your DVD files. This is where DVDA puts the _ts folders.
Steve Mann
MannMade Digital Video
http://www.mmdv.com