[LINUX] HOW-TO get Digital Audio Pass-Through Output working on Linux with XBMC

Added more and more info from several topics. Can a mod change the title that appears in the topic lists (because it contains a typo now)? And, if acceptable, maybe make it sticky?

I have this issue ofc and i tried it all here still no sound. I then went for the alsa upgrade script, totaly made the ubuntu hang instead. I think the xbmc live version also uses alsa 1.0.23 and that also hangs my system. so weird.....

After reverting for that script, the usb card isnt found at all anymore. I have a Sweex 7.1 usb card (C-Media CM6206 ). Anyone at all got that chipset to work?

br,

Ravee

ravedog Wrote:I have a Sweex 7.1 usb card (C-Media CM6206 ). Anyone at all got that chipset to work?

Thats an USB audio card isn't it? Its supposed to work, be it that s/pdif output isn't all that great...

Hi mate,

Yeah its an usb card. I only get menu sounds sometimes, and distortion sounds (buzzes).

This is the card: http://www.sweex.com/en/assortiment/soun...ards/SC016

It only shows up in alsamixer when i got the integrated card activated in bios, else it does not show up at all. And when it does it only have a few settings (four sliders).

Thanks in advance,

PS. Thanks for a good guide btw, appreciate it! Ds.

Ravee

@ravedog

sounds like you have one then more device (ubuntu sees your usb camera as sound device for example) and then every time you reboot ubuntu puts them in a different order so when you issue alsamixer command (which by default pics first device) sometimes it works and sometimes not


will show you how many devices alsa sees, you should see something like:
card 0 ...
...
card 1 ...
...

so then when you do alsmixer make sure you specify correct sound device

for card 0
for card 1
etc...

also once you are in alsamixer you can press F6 to see list of cards being recognized

if ubuntu mixes device numbers on bootup every time, then your settings in xbmc will always be wrong (that was my case)
so then you have to force alsa to give same card numbers to given sound devices at bootup
check if this is your case and we can go through forcing how to force alsa correct numbers every bootup

Hi mate thanks for replying, ill test as soon as I can.

I checked my output from aplay -l, and after each reboot it still says:


first two being my internal card, last one being the one i need to use.

I reinstalled today as well (because i updated the alsa driver to 1.0.23 and that totally hangs the computer)

In my gnome alsa mixer i have four columns for my usb card, speaker, PCM, line and mic. Mic the only one being muted.
I have two chcekboxes, "PCM Capture source" & "IEC958 in". Last one is checked.

I followed the guide again and i only get silence or buzzes (different kinds of buzzes depending on what movie clip i play)

(oh and the only thing that is connected through usb on the machines is the sound card, mouse and keyboard)

Thanks for you help guys.

br,

Ravee

In (Gnome-)Alsamixer, could you have a look at the menu: "Tools > Properties of soundcard"? I hope that you can tick, and activate, more properties of your sound card. This because you did not mention an IEC958 (= digital audio passtru) OUT (you did mention the IN, however).

If Alsamixer does not report an OUT then dig. passtru is not (yet?) supported for your audio card. You could have a look at the box your card came to see if it is even advertised. Also, you could boot into Windows, install the drivers the card came with and try to determine if s/pdif OUT is supported in Win. If it ain't, then it will probably never be supported...

Good luck

Hi!

Thanks for reply, yeh the sound card was brought only for this and as advertised on the box:
* Full digital sound
* For 2.1, 5.1 and 7.1 speaker sets
* S/PDIF optical digital input and output
* Full-duplex recording and play-back
* Powered by USB, no power adapter required

I dont even have a menu option that is called "tools". I have edit but nothing i can change in there.

Oh well, going to windows then...

Ty for the help

br,

Ravee

I have been able to get it working for intel HDA cards on two systems

o Make pulseaudio output go to analog out
o in alsamixer, unmute spdif and spdif default pcm

This way, I easily get both passthrough and pulseaudio working smmothly side
by side.