Assuming that the AVI is converted and you have a wide-screen DVD in a file folder.
Each VOB is patched, the whole demuxed, then recompiled with new IFO files before burning.
This also assumes the disk contains one title (VTS_01_1.IFO).
Run 'DVD Patcher', load each VOB of the title (VTS_01_1.VOB VTS_01_2.VOB etc) one at a time and apply the patch.
Run 'Rejig', open in 'IFO' mode and 'Add' VTS_01_0.IFO
On right hand window, check box for both streams, select an 'Output Directory' and 'Process'.
Quit IFO Mode.
Run 'DVD Author Mode'.
Load the video and audio streams from the last step, select a 'Destination' and 'Create'.
The output can be checked with the media player before burning.