Created attachment 8609742 [details] Screenshot_2015-05-23-14-46-22.png See the attached screenshot.
It's on a Nexus 5.
I think Randall may have actually fixed this with the patch in bug 1166961.
I didn't make any changes to the standard controls so I don't think my patch will have any affect on this.
After looking into this a little, it looks like the video element is too large so not only is the bottom being cut off but the sides (and maybe top) as well. Works fine in chrome for android. Also works fine when flash is installed. But not sure if it is a web compat issue or bug in fennec.
When I load the page on aurora or nightly now the video controls looks different than in the screenshot. Specifically there's just a pause/play button in the bottom-left corner of the video, rather than the fennec video controls over top of the video. So I think the website has changed how they are showing the video. At any rate, it doesn't appear that the new controls are cut off, so I'm closing this as WFM.
Controls are no longer cut off, but on Firefox there's something missing. I've opened bug 1229757.