When you say "control buttons", are you meaning the playback controls across the bottom of the video? Or are you instead referring to Buttons you have inserted to control the movie?
Also, have you enabled the Section 508 compliance option?
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Apologies I should have been more clear - Yes I do mean the playback controls across the bottom of the movie, and the play button which comes up when the movie loads but does not autoplay. We have Accessibility options enabled. These buttons can all be tabbed to in newer browsers.