[mythtv-users] Audio not working via coax/spdif

Mir Islam mislam at mirislam.com
Sun Jun 29 21:43:52 UTC 2008

Hi just got a new sound card Diamond extreme with coax output. The sound 
is working fine outside of MythTV in regular desktop but not in MythTV.

In MythTV I have audio setup as following:

Audio Output Device: ALSA:spdif
Passthrough: ALSA:IEC958{AES0 0x02}
Max Audio Channels: 5.1 Upmix: Passive
Enable AC3/DTS to SPDIF passthrough checked

But no sound comes out of my AV receiver. I can start mplayer and play 
DVD or recorded programs from hard disk fine and AV receiver correctly 
identifies number of channels etc. In MythFrontend log I see this error:

2008-06-29 14:33:54.596 AFD: Opened codec 0x138f550, id(MPEG2VIDEO) 
2008-06-29 14:33:54.596 AFD: codec AC3 has 2 channels
2008-06-29 14:33:54.597 AFD: Opened codec 0x13d3150, id(AC3) type(Audio)
2008-06-29 14:33:54.599 Opening audio device 'spdif'. ch 6(2) sr 48000
2008-06-29 14:33:54.599 Opening ALSA audio device 'iec958:{ AES0 0x02 }'.
2008-06-29 14:33:54.698 AudioOutput Error: Channels count (6) not 
available: Invalid argument
2008-06-29 14:33:54.698 AudioOutput Error: Unable to set ALSA parameters
2008-06-29 14:33:54.698 NVP: Disabling Audio, reason is: Unable to set 
ALSA parameters

Some other info:

In mplayer config I have ac=hwac3.

mislam at neptune:~$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: CMI8768 [C-Media CMI8768], device 0: CMI8738-MC8 [C-Media PCI 
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: CMI8768 [C-Media CMI8768], device 1: CMI8738-MC8 [C-Media PCI 
2nd DAC]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: CMI8768 [C-Media CMI8768], device 2: CMI8738-MC8 [C-Media PCI 
  Subdevices: 1/1
  Subdevice #0: subdevice #0


More information about the mythtv-users mailing list