The work I've been doing for the past couple weeks can be found:
Bug 517363 - Preserve video poster aspect ratio when scaling
Bug 726904 - nsVideoFrame::GetVideoIntrinsicSize setting wrong sizefound in this post. Since I wrote that, I've been going back and forth with proposed patches, trying to get things working just right. It's not quite done yet, and it seems to be breaking ref-tests, so I'm going to apply for level one commit access so that I can push patches up and have the tests run on them. here. I've Had a lot of back and forth on this one as well, working to make sure it's up to par. I've got the fix ready to go, I just need to polish off a couple tests to make sure it doesn't break.