[mythtv] documentation on audio configuration

[Simon Kenyon]

from reading the commits over the last while it seems like you know what 
you are doing
but for us mere mortals setting up audio can be quite daunting

i have look at the documentation and the wiki and don't see any 
description of what the "new" audio capabilities are capable of
which is a bit of a shame seeing as how you have put all this effort 
into creating the code

so my request would be for some explanation of what is possible and 
perhaps some sample use-cases
and perhaps some sample recordngs (multchannel test and audio-video 
sync) which allow users to test the setup to make sure that it is doing 
what they think it is

thanks for your time
--
simon