HN previously had some discussion on an article that used IamgeMagick to do this correction on a video: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=8713070" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=8713070</a>