To reproduce: 1. run-webkit-tests media/video-size-intrinsic-scale.html The test fails. You can see the diff of the failure here: <http://build.webkit.org/results/Windows%20Release%20(Tests)/r42320%20(45)/media/video-size-intrinsic-scale-diffs.txt>.
<rdar://problem/6769968>
This is due to a bug in WebKit, not a bug in the test. The end-user effect of this bug is that videos which are saved with a non-identity scaling transformation will display at the wrong size. However, Eric Carlson says that few videos are actually saved like this, so this will probably not affect many users/videos.
http://trac.webkit.org/changeset/42939