Proposals to release movies in theaters and DVD simultaneously got a big boost Tuesday with the release of an international report maintaining that film studios could realize a 16-percent boos in revenue by closing the current window between theatrical and DVD releases. On the other hand, the report -- by Marketing Power -- indicated that movie theaters would encounter a 40-percent fall in ticket sales. The report also suggested that studios could gain additional revenue by releasing films on home-video rental first, then selling the video three months later.