I know this sounds odd so I’ll try and be a little clearer….
I was first made aware of the problem when I sent some screeners back to my client who informed me that the aspect ratios were jumping around when he tried to capture the footage into a widescreen premiere project. I ran a few tests myself and noticed that when i played the outputted sequence through the premiere capture tool the preview window was jumping in size from 4:3 where the black was and then back to 16:9 at the point where the footage began. I then ran the tape through my camcorder and noticed that the same thing was happening on the view finder. I could tell that the aspect ratio was changing because the transport controls on the viewfinder change position according to whatever aspect ratio is on the tape. So that is how i can tell that the black image is being displayed as 4:3.
Basically it seems that any material that Avid has generated, i.e. fillers and graphics won’t output in 16:9. However the original footage that is on the same timeline is outputting in the same 16:9 aspect ratio that it came in as.
Hope this makes more sense. Any helpful advice would be kindly received!