I want to create a DVD from the original VC-1 stream (1920x1080). I created (as basically described in
this thread by Jeremy Duncan) a Matroska file (with a DAR of 16/9), a Graph file and a AviSynth script. It opens alright in VirtualDub.
For AVStoDVD I tried two ways. First by resizing the HD stream inside of my original script to NTSC values (720x480), then by leaving the HD unchanged in size (i.e. 1920x1080). Both times AVStoDVD adds the video as 4:3. That can fortunately relatively easily be amended by manually editing the internal script used to open AVS files.
As for adding multiple audio tracks: when can that be expected to be implemented. What are you programming with? I see the language is VB6 but what program?