Mixed aspect ratio playback

[gsh]

I am trying to author a disc with both 4x3 and 16x9 aspect ratios and have them auto switch to display correctly. I'm using DVDLab Pro2.
I have 6 clips - 3 of each a/r.
Each clip is in it's own vts.
All menus are 4x3 (bridges used between sub menu and each vts)
Each vts has the properties set for the correct a/r.
However the resulting disc will not recognise the 16x9 clips correctly and plays them as 4x3.
My scart is fully wired and commercial discs switch between a/r automatically without problems.
I have tested on a LiteOn 5006B and an H&B DX-3255, the only 2 players I have available at present. (TV is widescreen and players are set to widescreen playback)
Playback from pc using Win DVD correctly switches a/r.
Interestingly when played back on a 4x3 tv using the LiteOn with all settings set to auto-letterbox the a/r is correctly determined and letterbox display is used on the 16x9 clips.
While it may not be a particularly big deal switching the tv to the correct display a/r I would prefer the disc to work properly.
Is there something that can be set (pgc edit or ifo edit perhaps) to force the correct a/r selection automatically for widescreen tv playback? If commercial discs didn't switch properly I would suspect it was a compatibility problem with my players/tv. As they do I assume it has something to do with the authoring.
Thanks in advance.

[tinker]

Try to reathor DVD using WMG menu. Bridge suppose to do same thing, but it could be problem how player reed it.
All commercial DVDs use WMG menu to navigate between different VTS.

[guns1inger]

Are the 16:9 movies encoded correctly as 16:9, with the 16:9 flag set ? In the assets list, do they show up as 16:9 ?

Is there a reason for 6 VTS's ? If the audio is the same for all clips then you only need two - one for the 16:9 and one for the 4:3 material.

I would create a single menu in the VMG domain, and separate menus in the 4:3 and 16:9 VTS to link to the movies themselves. You could, if necessary, add a bridge to link the two VTS's as well, but I would start simple and build on it once you iron out the issues.

[gsh]

All the clips are correctly encoded with the right flags set. You are of course right about only needing 2 vts - I had a brain fart there.
On further testing on different tvs and players I am leaning towards it being actually the tv - every disc I tried on 4x3 tvs (including this one) correctly switched a/r. I'll burn a few discs of the project and send to friends for testing.
Thanks for the replies.

[guns1inger]

One thought.

I live in PAL land and have a Loewe 4:3 TV with 16:9 switching. My DVD player is set to output 16:9 widescreen for all 16:9 discs, including widescreen avi files. For all PAL material that is correctly encoded, it switches without fail (Paramount still don't know how to correctly author 16:9 discs, BTW).

For NTSC material, it is not so consistent. Widescreen avi files do not automatically switch. Most NTSC DVDs do switch, but not all.

As for software players - I think they cheat and look at other factors that standalone players might not consider, simply because they can.