I am a bit confused. I believe Avid uses non-square pixels,(4×3) 720×486 or for a DV codec 720×480. When you export from Avid, you have options to export in pixel ratios and another setting to set the “display” – whether i am exporting 4×3 or 16×9 AND I am exporting for Encore, I export native dimensions and I generally don’t care what the “display” setting is. I export a QT Ref. and inside of Encore, I do nothing if it is 4×3, but if it is 16×9, I right click (PC) the asset and tell it to interpret footage as WS. I then have a custom setting to encode as WS and the DVD should playback fine – when you adjust the “interpret footage as”, the monitor window should show the timeline for that asset in the correct aspect ratio. Maybe this will help … as I said, I am a bit confused as to what you are asking.
Ricky