Has this ever worked, or has the problem just started? Have you tried different connections (HDMI versus Optical, etc.)? Does it happen on all sources (live TV, recorded programs, OTA, etc.)? Does it happen with all sound processing options on the Pioneer? Have you set all the config options on the Pioneer back to default (so that you know there's nothing funky hidden in there)? What happens if you bypass the Pioneer - does the problem still exist?
It may be that you don't have an actual "problem" as a lot of receivers induce a discernible lag - it just takes time to do all that clever signal processing. You didn't mention which DirecTV receiver you have, but there may be an option to adjust AV sync. I'm not familiar with the Pioneer receiver range, but you could try different settings, like adjusting the seating distance - your model seems pretty well equipped, so there might be a specific setting to address audio/video synchronization.