[MPlayer-users] dvd audio stream selection

[Robert Henney]

I've been curious as to how mplayer goes about choosing an audio stream
on a dvd in certain circumstances.  I've looked through the audio
sections of the documentation but haven't found an answer there.

when using -aid, the expected stream is used. nothing confusing there.

when using -alang, I believe that the first stream with a matching
string id is used.  though not sure if it's from lowest or first by 
order.  anyhow, to get on to my main question..

when using neither option though, how does mplayer select the default
audio stream?  a seemingly random (but consistent for each dvd) stream
is choosen by mplayer for me.  I'm sure there's some criteria being
emplayed, but I don't know what it is and it frequently falls onto a
less than ideal stream, such as one with an incorrect number of audio
channels for what was given with -channels, when a different stream
would have matched the correct number of channels.  another curiosity is
that the stream that gets automatically chosen does not appear to get
identified in the output, even with -v.  it'd be useful to know. :)

I do already know one way around this issue is to run with -v and then
choose and force with -aid, but is there some way to tell mplayer to
prefer streams which have the number of channels given with -channels
over streams that don't?  just seems that if it is already trying to
select a preferred stream based on some criteria, taking into
consideration the number of audio channels would be a nice bonus.