[mythtv] Analog (v4l) tuner card audio sample rate

Michael T. Dean mtdean at thirdcontact.com
Sun Feb 25 18:22:25 UTC 2007

On 02/24/2007 04:25 PM, Ed Winde (mythtv-dev) wrote:
> I'm trying to setup a Kworld ATSC-110 (hybrid) DVB/analog tuner card 
> under mythtv  After building from the subversion source, mythtv-setup 
> allows me to configure both halves (digital and analog) of the card.  
> (Yea!)
> The digital portion of the cards is working well - but tuning to an 
> analog channel gives me "stuttering chipmunk" sound - a cycle of a 
> second or two of audio played too fast, followed by a second or two of 
> silence.  The console reports "prebuffering pause" and audio 
> underruns.  My interpretation is that the tuner card and myth aren't 
> agreeing on the audio sampling rate.
> One of the mythtv-setup options for the analog portion of the card is 
> "audio sampling rate limit".  I've set that to 32000 - but I don't see 
> any change with that limit set.  I also played with the audio sampling 
> rate in the "LiveTV" recording profile, and had brief success, but 
> that no longer seems to work.
> My understanding of the "audio sampling rate limit" is that it 
> indicates the highest rate at which the card can provide audio 
> samples.  If this is correct, it should override the sampling rate set 
> in the recording profiles.  (True?)  If so, something isn't working.  
> If someone could point me towards the right section in the code, I'd 
> be happy to investigate further. 

I think you're going the wrong way.  You need to set the sampling rate 
to 48kHz (or fix your ALSA configuration).  It's playback--not 
recording--where there's "disagreement".


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