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?
This is not the correct device. This is a software encoder that is not
installed on your computer. It will degrade audio quality by compression, eat CPU time, kill PulseAudio for exhausting the real-time budget, and is generally not needed on HDMI, because HDMI can transport PCM 5.1 streams just fine.
https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/commit/sound/pc...
Multi channel lpcm seem need AC_WCAP_CHAN_CNT_EXT
+ if (wid_caps & AC_WCAP_STEREO) { + unsigned int chans; + chans = (wid_caps & AC_WCAP_CHAN_CNT_EXT) >> 13; + chans = ((chans << 1) | 1) + 1; + if (chans == 2) + snd_iprintf(buffer, " Stereo"); + else + snd_iprintf(buffer, " %d-Channels", chans); + } else