Directsoundsink and surround sound

[Wouter Klouwen]

Hi all,

I have a machine that supports 5.1 surround sound through three seperate 
3.5mm jacks (Front LR, Rear LR & centre).  When I use some 5.1 test 
files, such as a Dolby 5.1 channel check mp4* or a simple 6 channel wav 
file^, what happens is that even with the jacks plugged in, gstreamer is 
putting everything through the Front LR jack, instead of using the rear 
and centre outputs.

To play back the mp4, I used playbin, eg:
gst-launch-1.0 playbin uri=file.mp4
To play back the wav file I used a number of options:
gst-launch-1.0 filesrc location=file.wav ! decodebin ! audioconvert ! 
directsoundsink
as well as
gst-launch-1.0 filesrc location=file.wav ! decodebin ! audioconvert ! 
"audio/x-raw,channels=6" ! directsoundsink

This is using gstreamer 1.0 on Windows.

How can I make it output the rear LR channels to the available extra 
channels?

Thanks

*: http://download.dolby.com/Content_Download/channelcheck-small.mp4

^: http://www.jensign.com/bdp95/7dot1voiced/