“A DVD is comprised of one or more video title sets (VTSes), which contain video information in the form of MPEG-2 video streams. Each disc can have up to 99 VTSes, and each title set can be subdivided further into as many as 99 chapters, allowing DVD players to jump to a certain point within the video stream. Within each VTS, a DVD can have up to eight different audio tracks and 32 subtitle tracks that the viewer can switch between at will. A menu system can be included within a title set, allowing the viewer to select between the different subtitle and audio tracks. An optional top-level menu, known as the video manager menu (VMGM), is used to navigate between the different title sets.” – Ian Pointer, in linuxjournal

authoring with GNU/Linux

• http://www.linuxjournal.com/article.php?sid=6953
• Free Media Tools

dvd→avi in osX using any of the following…

• HandBrake (simple to use, good compresion controls, no subtitles, multiple audio tracks)
• forty-two (one click, subtitle capable, but somewhat erratic with the soundtrack)
• ffmpegX and/or xvid

assuming a correctly laid out VIDEO_TS folder, this hint should work on osx http://www.macosxhints.com/article.php?story=20070612161317338&mode=print

hdiutil makehybrid -udf -udf-volume-name DVD_NAME -o MY_DVD.iso /path/to/VIDEO_TS/parent/folder