semicolon-delimited attr value, and "camcorder"!
Great to see that the future is being ushered in in a coordinated, organized, well-thought-out manner. Ugh.
That syntax came from MIME and has been present in email, newsgroups and the web for as long as I can remember. The server sends content-type headers delimited with MIME attributes, the browser sends accept headers and inside the pages one will often find a meta tag with its content attribute delimited that way.
HTML5 Media Capture[1] provides extensions to input tags to allow access to camera and microphone devices, eg:
<input type="file" accept="video/* ;capture=camcorder">
<input type="file" accept="audio/* ;capture=microphone">
It isn't widely implemented though (just in the Android Browser, Chrome on Android and Firefox Mobile).
The recommended way is to use the getUserMedia Javascript APIs. http://www.html5rocks.com/en/tutorials/getusermedia/intro/ is a good guide.
[1] http://dev.w3.org/2009/dap/camera/