[aragorn]

Ok folks, i've read thru the various threads and other things i could find online, but i'm a bit stumped.

Basically i'm using a USB soundcard, and while normal 2 channel audio (say playing an MP3) works perfectly over the SP/DIF output, i simply cant get the AC3 passthrough to work.

The bit that confuses me, is that the sp/dif threads seem to suggest that "aplay -l" should give two devices, one for the normal stereo output, and another for the IEC958 output. I've tried two different USB soundcards, and neither of them does this.

I get this:

Code:

xbmc@xbmc:~$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 2: default [USB Sound Device        ], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

and this:

Code:

xbmc@xbmc:~$ aplay -L
pulse
    Playback/recording through the PulseAudio sound server
front:CARD=default,DEV=0
    USB Sound Device        , USB Audio
    Front speakers
surround40:CARD=default,DEV=0
    USB Sound Device        , USB Audio
    4.0 Surround output to Front and Rear speakers
surround41:CARD=default,DEV=0
    USB Sound Device        , USB Audio
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=default,DEV=0
    USB Sound Device        , USB Audio
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=default,DEV=0
    USB Sound Device        , USB Audio
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=default,DEV=0
    USB Sound Device        , USB Audio
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=default,DEV=0
    USB Sound Device        , USB Audio
    IEC958 (S/PDIF) Digital Audio Output

I've tried Ubuntu 9.10, 10.04 and the current XBMC Live disk and get the same output for all three, with both soundcards (one an unbranded ebay special, and the other an "Asonic" item from a local store)

As you can see, there is an iec958 device under the "-L" listing, but i'm not really sure how to utilise this?

Hopefully someone can help!

Cheers
Kev

[bobo1on1]

iec958 is the spdif output, if you set that for passthrough in xbmc it should work.
I'm not sure how that's done in the 9.11 release, thing have changed quite a bit in that regard.

[aragorn]

As i say, i select that and i get the "unable to initialise audio device" message for passthru audio.

I've just tried this:

Code:

speaker-test -D iec958:CARD=default,DEV=0

which i understand should work, however i get this:

Code:

xbmc@xbmc:~$ speaker-test -D iec958:CARD=default,DEV=0

speaker-test 1.0.22

Playback device is iec958:CARD=default,DEV=0
Stream parameters are 48000Hz, S16_LE, 1 channels
Using 16 octaves of pink noise
Channels count (1) not available for playbacks: Invalid argument
Setting of hwparams failed: Invalid argument

Then i tried:

Code:

xbmc@xbmc:~$ aplay -D iec958:CARD=default,DEV=0 SURROUNDTEST_DD_640.wav
Playing WAVE 'SURROUNDTEST_DD_640.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

Which results in white-noise from the amp, and no "Dolby Digital" detection.

[aragorn]

No ideas?

I seem to have managed to frag the whole sound layer trying to update ALSA, so it looks like fresh install time, but i'm still no further forward...

I guess a better question might be, can anyone tell me of a USB sound card which WILL work? I'm not a great fan of crappy unbranded hardware, because like this, when things dont work properly no-one seems to have a clue.

On the other hand, from what i can make out its not a lot easier trying to get branded cards like Creatives offerings working either.

[Goga777]

iec958 is the spdif output,

where is iec958 configured ? my alsasound.conf and asoundrc doesn't include any info about alsa virtual device as iec958

[aragorn]

Its a device or alias created by ALSA.



FWIW i've uninstalled pulseaudio, and tried again, and now i've stopped getting the "unable to initialise" message, however i'm still getting the garbage from the speakers when playing AC3 soundtracks.

I'm assuming its something to do with the hardware, so i've ordered another new soundcard (PCI one this time) in the hope that by buying something quality i'll actually get somewhere. I just need to hope i can squeeze it inside the case. I have a soundblaster live sat here, but it simply wont fit.

[Goga777]

Its a device or alias created by ALSA.

where is config for it ?