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

Dan Christensen jdc at uwo.ca
Mon Nov 8 01:06:48 UTC 2010


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
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
        Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0 (500ns min, 1250ns max)
        Interrupt: pin A routed to IRQ 23
        Region 0: Memory at d9180000 (32-bit, non-prefetchable) [size=16K]
        Capabilities: [44] Power Management version 2
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot+,D3cold+)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-
        Kernel driver in use: HDA Intel
        Kernel modules: snd-hda-intel


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