a lot of people use the WP audio player plugin (as we do) with its old-fashioned (pre-shortcode) syntax, so it would help people to switch to this plugin if there was a 'compatibility mode'
I'm hoping the blog authors will let me switch to your plugin, but to do that would take a bit of magic to go back and update all our audio embed codes. there's a couple of global search and replace plugins i know could do this, but until everyone is happy with the switch, I don't want to make those changes.
so instead I've added this extra code after your "extract( shortcode_atts ..." line (at about line 56)
# get audio player attributes
if ($src=="" && $atts[0]!="")
{ $src=trim($atts[0],": \t");
$src=explode("|",$src);
$src=$src[0]; # just parse out the src for now. other params like Titles= could be used in a later version
}
(I have another plugin that makes your autodetect fail, so added a $format="mp3" in there too)
hope this helps