[mythtv-users] how to tell if 5.1 audio channels mapped correctly?

[James Courtier-Dutton]

On 8 November 2010 01:06, Dan Christensen <jdc at uwo.ca> wrote:
> James Courtier-Dutton <james.dutton at gmail.com> writes:
>
>> On 4 November 2010 15:57, Dan Christensen <jdc at uwo.ca> wrote:
>>
>>> When I run ALSA's speaker-test program (speaker-test -twav -c6), it gets
>>> left rear & front center reversed; and also right rear & LFE reversed.
>>
>> I wrote that speaker-test program.  It tests ALSA.
>> ALSA has a fixed channel ordering so that all applications can use the
>> same order.
>
> I read that sometimes mplayer gets it right while other players get it
> wrong, so I guess things are pretty complicated.  Here's a thread that
> mentions this in the context of wrong channels using speaker-test:
>
>  http://www.spinics.net/lists/alsa-devel/msg24541.html
>
>> If the speaker-test program is getting the order wrong, then the
>> problem is one of:
>> 1) Speaker wires connected wrongly.
>> 2) ALSA driver bug.
>
> The speakers are connected correctly, so it looks like an ALSA bug.
> I've got Debian's 1.0.23+dfsg-2 user space and kernel
> 2.6.32-5-686-bigmem.  Any idea if this would be fixed with newer
> versions of either of these?  My "lspci -v" output is below.
>
>> Another test to try is:
>> speaker-test -twav -c6 -Dplug:surround51
>
> I'm using hdmi, so I do -Dhdmi or -Dhw:0,3 .
>
> Thanks for your input!  Let me know if I can provide any other info, or
> if I should move this to an ALSA list.
>
> Dan
>
> 00:08.0 Audio device: nVidia Corporation Device 0ac0 (rev b1)
>        Subsystem: Giga-byte Technology Device a102
>        Kernel driver in use: HDA Intel
>        Kernel modules: snd-hda-intel

Yes, take it to the alsa-devel mailing list.
It is an ALSA bug, or to me more correct, ALSA does not know about
your particular variant of sound card so it has not been told how it
is wired.

You will need to paste the output of
cat /proc/asound/HDMI/codec#0

This will allow them to add a quirk for your particular hardware.

I do not do development for that particular sound card type so you
will need help from other ALSA developers.

Cheers

James