[mythtv-users] 5.1 wrong speaker problem - SOLVED

[Ken Bass]

On 1/26/2011 1:37 AM, Ken Bass wrote:
> Just upgraded to 0.24-fixes from 0.23. I have some recordings that are 
> in 5.1. If I recall, I think for me using 0.23, I only ever got 
> stereo, even on 5.1 material, so this 5.1 stuff is a new feature for me.
>
> My frontend sound output is set to ALSA:hdmi:CARD=NVidia,DEV=0 (its an 
> ION)
>
> When I playback a 5.1 program, the center channel seems to be going to 
> the REAR left. How can this happen?
> Shouldn't the sound be sent unmolested directly to my audio receiver 
> and it would decodes it there?
> These recordings were make using a HD-PVR ( w/ SPDIF )

This is an ALSA bug. The NVIDIA MCP79/7A HDMI hardware has incorrect
channel mapping.

The Center channel and LFE was swapped with the Rear Left and Rear Right.

The workaround is to add the following to the asound.conf

  pcm.!hdmi {
      type             route
      slave.pcm
"cards.HDA-Intel.pcm.hdmi.0:CARD=NVidia,AES0=0x4,AES1=0x82,AES2=0x0,AES3=0x2"
      ttable.0.0 1
      ttable.1.1 1
      ttable.2.4 1
      ttable.3.5 1
      ttable.4.2 1
      ttable.5.3 1
      ttable.6.6 1
      ttable.7.7 1
  }

See: http://www.spinics.net/lists/alsa-devel/msg39694.html