Hi Guys, Thank you for your input it's much appreciated.
I have now produced the pulse audio log as suggested and it appears
that
when an attempt to open the Digital Surround 5.1 device, it fails with a "No such file or directory" error. Here is a snippet of the log showing
the
error.
( 0.456| 0.000) D: [pulseaudio] alsa-mixer.c: Looking at profile
output:iec958-ac3-surround-51
( 0.456| 0.000) D: [pulseaudio] alsa-mixer.c: Checking for playback
on Digital Surround 5.1 (IEC958/AC3) (iec958-ac3-surround-51)
( 0.456| 0.000) D: [pulseaudio] alsa-util.c: Trying a52:1 with
SND_PCM_NO_AUTO_FORMAT ...
( 0.456| 0.000) I: [pulseaudio] (alsa-lib)pcm.c: Unknown PCM a52:1 ( 0.456| 0.000) I: [pulseaudio] alsa-util.c: Error opening PCM device
a52:1: No such file or directory
So I guess the next question is what is responsible for producing the required device?
http://git.alsa-project.org/?p=alsa-plugins.git;a=blob;f=doc/a52.txt;hb=HEAD
card number and channels are hardcoded