[clug] alsa config for MythTV (spdif)

David Cottrill cottrill.david at gmail.com
Tue Jan 5 01:03:49 MST 2010






On 05/01/2010, at 6:23 PM, Paul <mylists at wilsononline.id.au> wrote:

> On 5/01/2010 6:17 PM, Jeff Stiff wrote:
>>
>>
>> 2010/1/5 Paul <mylists at wilsononline.id.au
>> <mailto:mylists at wilsononline.id.au>>
>>
>>    In the last few months even after upgrading MythTV and Fedora
>>    (currnetly 12), I have been getting these " WriteAudio: buffer
>>    underrun" messages in my Mythfrontend log which causes pauses  
>> during
>>    playback.
>>
>>    So I'm trying to review my ALSA setup which I admit I just copied
>>    from the Wiki, so if anyone has some advice I would be glad to  
>> hear it.
>>
>>    I'm using an on board nvidia sound card which I'm outputting my
>>    SPDIF to my AMP.
>>
>>    Note the current setup does produce sound and it seems good to me
>>    but perhaps if there is a way to optimise the buffers perhaps this
>>    might fix the issue I have with the buffer underrun.
>>
>>
>>
>>    # cat /etc/asound.conf
>>    #Generated by system-config-soundcard
>>    #If you edit this file, don't run system-config-soundcard,
>>    #all your changes here could be lost.
>>    #SWCONF
>>    #DEV 0
>>    defaults.pcm.card 0
>>    defaults.pcm.device 0
>>    defaults.ctl.card 0
>>
>>
>> Sorry Paul, I can not help with the asound.conf file, as none of my  
>> Myth
>> machine (3) have that file.  However, I do wonder if the pauses are
>> caused by the buffer underrun you reported. As my logs are full of  
>> the
>> same WriteAudio: buffer underrun message, they seem to be a few  
>> seconds
>> apart, but I do not notice any pause when watching anything,  
>> including HD.
>>
>> I seem to recall something to do with the video causing stuttering, I
>> will have a look to see if I can find what that was.  But I would
>> probably stop looking at the audio at present, and focus more on the
>> video settings.
>>
>> Hope this helps,
>> Jeff.
>
>
> note mine are appearing exactly every 60 secs not sure why but if  
> seems to occur mainly on the ABC digital recordings..
>
> thanks
> -- 
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Can you please post the sections of dmesg related to the sound and  
video cards. It is possible the sound drivers are conflicting with the  
video drivers. I ran into the intertwined nature of these through the  
openchrome drivers and HDMI
Also a quick grep of syslog might be in order. Are you using  
proprietary drivers?
David 


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