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

Alen Edwards allen.edwards at oldpaloalto.com
Mon Jun 30 05:02:23 UTC 2008



Mir Islam wrote:
>
>
> Alen Edwards wrote:
>> Mir Islam wrote:
>>  
>>> 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) 
>>> type(Video)
>>> 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 DAC/ADC]
>>>   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 IEC958]
>>>   Subdevices: 1/1
>>>   Subdevice #0: subdevice #0
>>>
>>>
>>> Thanks
>>> Mir
>>>     
>>
>> Have you tried "default" as the audio output device?  Keep your 
>> bypass device as is and you should get spdif out.
>>
>> Allen
>>   
> Setting audio output to default did not work either. Any other idea?
>
> Thanks
> Mir
>
>
Well, I assume you have turned spdif output on in the mixer? It is off 
by default by some strange thinking.  But as that is the first thing 
people suggest,  you have probably already done that.

Basically, I have both bypass boxes checked, the bypass output sent to 
ALSA:IEC958{AES0 0x02} like you do, and the mixer turned on.  I don't 
think the defalut setting should matter, actually, but i was surprised 
that your error log looked like ALSA was getting input from that 
setting.  You should be able to delete (or rename) the ALSA control file 
(don't remember the name.  Check your cable by plugging into another 
source...  Can't think of much else...

Allen


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