[mythtv-users] no sound sblive alsa livetv

Bruce Markey bjm at lvcm.com
Thu Dec 9 02:30:28 UTC 2004

Technical wrote:
> aplay /usr/share/sounds/info.wav  works

Which indicates the PCM is turned up so that's not the problem...

> here is what I got:
> Playing raw data '/dev/dsp' : Unsigned 8 bit, Rate 8000 Hz, Mono
> underrun!!! (at least 10.579 ms long)
> What does underrun mean?

It means the driver is loaded =). You wouldn't see these if
it could not access the device file and when it is working
correctly, you will see these messages and hear sound.

It all looks good but there isn't anything here to verify
that there is any audio signal coming from the card. Try plugging
headphones or speakers into the audio out from the capture card.
One potential problems is that many cards with s-video or composite
inputs also have an audio-in jack and may have the same size IR
jack. Make sure you've actually plugged into the right hole. If
there is still no sound it is either a driver problem or bad

If there is sound out of the headphones then plug the patch
cable back in. Same caution for the sound card. Make sure it
is really the line in. If it is, you should be able to hear the
realtime analog passthru audio when running xawtv with Line
unmuted. Once that works, mute Line again and "aplay /dev/dsp".
This should work unless 1) Line is not set as "CAPTUR" 2) the
"Capture" slider is not turned up 3) /dev/dsp is not right
because it may be /dev/dsp1 if there is another device or 4)
your soundcard or soundcard driver is failing to do the job.

--  bjm

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