Why can't we author DVD with menus from VOB files?

[N47H4N]

Maybe this ain't the best place to ask the question...
but hey, it's not like I read any other forums.

Why do all the DVD authoring programs require encoded mpeg video to make a DVD with nifty menus?

Is not all the same "stuff" contained in the VOB files?

I ask mainly because I would like to find an easier way to make DVDs with menus from extracted TiVo content. And it also seems to me (a novice) that with demux, mux, demux, remux, supramux etc. that some kind of quality has got to be getting lost? (theoretically speaking of course)

[captain_video]

SpruceUp and DVD Maestro do not require muxed audio and video for authoring DVDs and, aside from using IFOEdit, are the easiest authoring tools available for creating DVDs with menus directly from a split ty file.

Muxing and demuxing the audio and video components should not affect picture or sound quality as nothing is being altered from the original streams. All you are doing is combining or separating the two components to create an mpeg stream. You only run the risk of losing quality when you do any sort of transcoding (i.e. changing resolution formats).

The same "stuff" is indeed contained in the VOB files. It's just that a tystream is not a DVD-compliant mpeg format. There has been a lot of work going on to create a proper mpeg stream from a tystream so that Tivo video files can be edited and processed with standard off-the-shelf DVD authoring software. Editing is the main reason for this process as there is no easy way to perform this function without loss of audio sync and other issues.