[mythtv] Internal DVD Player multichannel support

[Ed W]

I'm working up to some changes on the audio code to neaten up a few 
things which have been bothering me for a while

- What do we need to do to get multichannel audio working with the 
internal DVD player?  Presumably some way to set the number of speakers 
the user has is a pre-req?  I guess that libavcodec can do the 
downmixing for us though?  I'm interested to do some work on this

- Unrelated, but I have a lot of problems with FF/RW which doesn't work 
right on any of the films I tried so far - is this a known issue?  Basic 
problem is that the timecode goes up and down the correct amount for the 
keys I am pressing, but the actual video moves much less, so if you FF 
then you quickly get to the timecode saying it's at the end of the film 
(and hence you can't skip any further), but the video is perhaps only 
10-20 mins into the film - known issue?


Lovely addition though - congrats

Ed W