At least under Safari 3.1, the <video> element seems to like to hide its controls when you're not using them, and is just an invisible rectangle while an audio file is playing.

Did a quick hack test under Safari 3.1; <audio> appears to work correctly just substituting in for <video>, but without hiding the controls, so it's more usable.

Haven't tested with Firefox or Opera builds that support <video>; unsure whether they also support <audio> at this time. May be wise to test support for them separately.

Version: unspecified
Severity: enhancement
URL: http://commons.wikimedia.org/wiki/Image:Pachelbel%27s_Canon.ogg