Audio out via HDMI... how?

[Denise H. G.]

On 2012/10/10 at 06:11, "Ronald F. Guilmette" <rfg at tristatelogic.com> wrote:
> 
> [[ I didn't get much in the way of traction on this question over in
>    freebsd-questions, so I am posting it again here, in the hopes that
>    I will have more luck here.  ]]
> 
> 
> I have a laptop which has an HDMI output port.
> 
> I can get _video_ out of that (with xbmc) just fine.  Audio, not so much.
> Like not at all, as far as I can tell.
> 
> So anyway, here is what I get when I do "cat /dev/sndstat":
> 
> pcm0: <HDA Realtek ALC888 PCM #0 Analog> (play/rec) default
> pcm1: <HDA Realtek ALC888 PCM #1 Analog> (rec)
> pcm2: <HDA Intel Cantiga HDMI PCM #0 HDMI> (play)
> 
> I have the HDMI output wired into my everything-capable Sony 5.1 channel
> receiver, which then, in turn, is wired into my 4 (count 'em four) speakers.
> 
> OK, so now, could somebody please just tell me how I can do a test
> that will determine why I ain't gettin' no audio?  (And by the way,
> what I am *really* trying to do here is to run xbmc.  But no audio
> is coming out of that... at least not via the HDMI port... so I'm
> stuck tying to dredge into this problem at a deeper level.  Oddly,
> when running xbmc on the laptop, there _is_ 2channel sound coming out
> of the tinny little built-in speakers in the laptop.)
> 
> So anyway...
> 
> My intelligent HDMI-switching handles-everything receiver is capable
> of decoding 5.1 DTS-HD, Dolby TrueHD, and eveything else too.  The
> receiver is working just fine.. not a thing wrong with it.  It works
> great with my Blu-Ray player and does the digital->analog decoding for
> anything and everything I throw at it.
> 
> Again, I just want to know:  How does one go about TESTING audio output
> via a laptop HDMI-out port?  I tried these things (while the laptop's HDMI
> port was wired to my receiver), but not a sound was heard:
> 
>    cat /dev/random > /dev/dsp
> 
>    cat /dev/random > /dev/dsp2
> 
> (Note that before I ever did this test I set hw.snd.default_unit=2.)
> 
> The FreeBSD handbook page that deals with setiing up audio cards doesn't
> provide a whole lot of guidance for how to test and/or fix digital audio
> output, whether it is coming out via HDMI (as in my case) or via any other
> kind of physical transport (e.g. coax or S/PDIF).
> 
> Somwebody please pass me a clue.  I'd really like to get this working.
> Thanks.
> 
> 
> Regards,
> rfg
> 
> 
> P.S.  Even if I end up, in the end, downmixing all my audio to 2 channel,
> in xbmc, before the audio even hits the HDMI cable, I could live with that.
> Bu right now, as far as I can tell, I can't get _any_  kind of audio flowing
> down that HDMI cable at all, period.

I think you might take a look at those sysctl things. Just run:

sysctl dev.hdaa

to see what is comming out. Normally you can find in the output
something like:

dev.hdaa.X.nidY_config: .....
dev.hdaa.X.nidZ_config: .....

Some of which are labeled 'Speaker', some 'Headphones', and some
'Digital-out' which I guess is a HDMI output.

The point is you have to associcate your 'Speaker' with 'HDMI' I think.
That is to say, if your 'Speaker' has a configuration of 'as=1 seq=0',
then your 'Digital-out' must have something like 'as=1 seq=15' or
something. The numbers I just made up, you have to do them according to
your machine output.

This is just a FYI. Hope it would work for you.