[html5] <video> tag fallback

[Steven Garrity]

We're working on implementing the <video> tag to play a Ogg Theora video 
for a client. We're including a Flash playing in the "fallback content" 
for Internet Explorer.

We're running into trouble with the lack of a common format, though. It 
seems the current behaviour in Safari is that if the video format is not 
supported (Ogg Theora, for example), then the <video> player is shown 
(empty) rather than the fall back content.

Is this the intended/spec'ed behaviour when no video format playable by 
the client is provided?

We've also attempted to work around this with the canPlayType() 
Javascript function to check for format/codec support and output a Flash 
play if the provided format(s) are not supported. However, Safari 
doesn't seem to have the canPlayType() function at all.

Are we up a creek?

Please note that I know we can provide a Safari-playable video format as 
well as a secondary source in the <video> tag. We'd like to avoid having 
to add another (third, if you count ogg+flash) format, especially 
another proprietary format. Also, if other vendors release 
<video>-capable browsers, who knows what formats they'll support.

Thanks,
Steven Garrity