This started only recently, perhaps with one of the recent updates. But when I am exporting out of premiere pro cs5 - in both .mov or .mpeg2 (havent tryed others) if i export the entire work area bar as u see it in the timeline and dont trim it a couple frames in the export options - the quality of my final render sucks big time, massive aliasing artifacting just looks horrid. Now if i add a couple black frames onto the end of my timeline and extend the work area bar to include these new back frames, THEN trim the work area in the export options and render the quality is great - just what i wanted. WHAT THE HECK! oh and to confuse u further i can make my work area bar tiny in the timeline (to export quality test shots with low render time) and dont trim it in the export options the quality is perfect!.
Please help me out - just finished 20 hours of rendering and from all my small tests everything was perfect but when i went full length it all looks like crap
Though it also gives the link that John T provided, this ARTICLE might give some tips on filing that Bug Report. The more info that you can provide Adobe with, the easier it will be for Adobe to first replicate the issue, and then get about fixing it.