[MPlayer-dev-eng] mplayer sets number of channels incorrectly

[Alexander Macdonald]

I sent this to mplayer-users but it hasn't got through, also this might be a 
better list since the question is related to me poking around with the code.

Hi,

I have a surround sound setup so when I play a 2-channel sound I'd like it to be 
upmixed(just copy the channels, nothing fancy) alsa does this nicely for me. 
However when I play a dvd or something with 5.1 sound mplayer downmixes it to 2 
channels , I can get around this by passing mplayer "-channels 6" and it 
correctly plays the file . the problem is that when I play a 2 channel file with 
"-channels 6" mplayer sticks in blank channels which stops the upmixing from 
happening..... Is there any way I can tell mplayer to just use the number of 
channels from the file? Or do I just not understand what is going on?