Audio out via HDMI... how?

Discussion:

(too old to reply)

Ronald F. Guilmette

2012-10-09 22:11:25 UTC

[[ 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.

L. Adriel T.

2012-10-12 14:48:32 UTC

Permalink

Hi,

One thing I might suggest to try is to install the PC-BSD distribution
on a spare disk etc, and see if the hardware works as expected then.

If so, note the differences in configuration. A lot of the PC-BSD
components are 'plug and play' so it might be an option for you. Kind
regards

Post by Ronald F. Guilmette
[[ 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.
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
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.
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http://lists.freebsd.org/mailman/listinfo/freebsd-hardware

Denise H. G.

2012-10-13 09:52:20 UTC

Permalink

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.