I have Ubuntu 14.04 installed (i386 Architecture) on Zotac ZBOX-ID18.
I am trying to output digital surround audio through digital SPDIF output, I understand that the default SPDIF output is on PCM format which is stereo only (not 5.1 surround).
I did install the AC3 plugin using the below as a reference, however even after selecting "Digital 5.1 Output" profile, I don't get any audio output at all.
https://help.ubuntu.com/community/DigitalAC-3Pulseaudio
I tried forcing this profile from default.pa and from pavucontrol but still no luck 🙁
Also tried running aplay -D a52:0 but not getting any output.
In some random cases I was able to output digital surround by playing test videos but it happened only few cases and couldn't relate this cases with any other events or config changes, it was pure random.
Best Answer
Finally managed to set this permanently, I had to add the following command in the startup applications.
pacmd set-card-profile 0 output:iec958-ac3-surround-51
To verify the name of you sound profile, run following command, u'll get all available profiled for ur sound card.
pacmd info
For some reason adding this default device in default.pa didn't work, but adding it as a startup command is working, now I don't need to open pavucontrol every time I reboot my machine.