[mythtv-users] SPDIF passthrough

Jason Jesso jjesso1607 at gmail.com
Tue Feb 5 16:14:12 UTC 2008


I am trying to output 5.1 audio through my sound card's digital output to my 
a/v receiver for decoding.  I cannot get this to work in Mythtv.  I can play 
the H.264/AC3 MKV file, but no passthrough to my receiver.

My current settings are:

Audio output device: ALSA:cards.pcm.iec958
Passthrough output device: ALSA:iec958:{ AES0 0x02 }

- Enable AC3 to SPDIF passthrough (CHECKED)
- Enable DTS to SPDIF passthrough (CHECKED)

What could be wrong with this?

I do have success with mplayer:
mplayer -afm hwac3 -ao alsa:noblock:device=hw=0.1 whatever.mkv

BTW, all channels are unmuted.  (works with mplayer)

The following is more sound hardware info:

$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: NVidia [HDA NVidia], device 0: ALC883 Analog [ALC883 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 1: ALC883 Digital [ALC883 Digital]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

$ aplay -L
default:CARD=NVidia
    HDA NVidia, ALC883 Analog
    Default Audio Device
front:CARD=NVidia,DEV=0
    HDA NVidia, ALC883 Analog
    Front speakers
surround40:CARD=NVidia,DEV=0
    HDA NVidia, ALC883 Analog
    4.0 Surround output to Front and Rear speakers
surround41:CARD=NVidia,DEV=0
    HDA NVidia, ALC883 Analog
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=NVidia,DEV=0
    HDA NVidia, ALC883 Analog
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=NVidia,DEV=0
    HDA NVidia, ALC883 Analog
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=NVidia,DEV=0
    HDA NVidia, ALC883 Analog
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
null
    Discard all samples (playback) or generate zero samples (capture)


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