If there is a bright side to piracy, it’s a useful tool for gauging consumer appetite — which might hearten the studios hoping the Academy Awards provide a bump to films as they make their way to homevideo. The big night did drive sizable spikes in worldwide file-sharing to four of the nine best picture nominees, as tracked by content protection firm CEG Tek Intl. across the final months of awards season. But it’s noteworthy that winning Oscars extended those spikes. Just look at “American Hustle,” which took no awards: The film’s piracy plateaued immediately afterwards, while “Dallas Buyers Club” and “Gravity” kept soaring. Best picture winner “12 Years a Slave” is on top, but grade that one on a curve: Its surge began the day its Digital HD release was available for pirates to illegally appropriate.