Which to use 16:9 or 4:3 for widescreen source?

[JustJay]

A simple question for the guru's.
I have an AVI source with an aspect ratio of 1.77:1 widescreen, what's the best method of encoding to MPEG2 for DVD using TMPGEnc 16:9 and let the DVD player add the black bars, or 4:3 and have the black bars encoded into the video.
I've tried both ways and don't really see a difference on my 32" set.
From a technical standpoint though which should give the best result?

[guns1inger]

A number of factors come into play - the quality of the source, the filters use pre and post resizing etc. If you are doing a simple encode, with as few other changes as possible, then a 4:3 letterbox will give you slightlt better quality as you don't have to resize as much vertically before encoding. If you are using avisynth or virtualdub to resize and filter before frameserving to your encoder then you can probably get the quality of a 16:9 encode to match that of the 4:3 letterbox, and perhaps slightly surpass it. Overall though, the difference probably doesn't warrent the extra work in most cases.

[celtic_druid]

Well chances are that your source doesn't have the vertial res to justify 16:9, but if you have a widescreen TV, then 16:9 really is the only choice. Otherwise you have to have your TV or player zoom in/stretch on the 4:3 source to remove the side bars and that never looks as good as doing it when encoding.