Both the interior and exterior of the Clinton Theatre are seen in Mike Jittlov's 1988 film "The Wizard of Speed and Time." A clip of a scene near the end that was filmed inside the theatre is on YouTube.
The theatre, at 526 N. Western Ave., was a 1938 design by Raphael Nicholais. It's still there but now used as retail space. See the Los Angeles Theatres page on the Clinton Theatre for more information.
On IMDb: "The Wizard of Speed and Time"