[mythtv-users] Background noise troubles

outlier314 at cox.net outlier314 at cox.net
Thu Sep 7 02:43:12 UTC 2006

outlier314 at cox.net wrote:
> I have been using MythTV a little bit for several weeks, but I have been struggling 
with this one problem since I began using it.  Anytime I watch TV (or any recordings) 
there is a ringing noise in the background.  At first I thought it was some kind 
interference, but both kdetv and TVtime sound just fine.  I tried fiddling with the mixer 
according to the howto instructions to no avail.  I also listened to the /dev/dsp output using
 aplay according to the howto and it sounded fine too.  This seems significant as it tells 
me that the sound stream is getting digitized without any problems (or am I way off track?).
  Any help would be much appreciated!
> Hardware notes-
> Tuner card: Leadtek Winfast TV2000 XP RM
> Audio: Integrated AC'97 on an MSI Nforce4 motherboard
Can you describe the "ringing"?
Do you have a mic somewhere?
You might take a look at your mixer and fade down all faders that are
not used.
Did you try playing a MythTV recording with mplayer to see if it's in
the recording?

brad fuller

The noise is a persistent high pitch whine. It is always there but tends to rise and fall in 
volume along with the audio. I can make a sample file if it would help.

I do have a mic, but unplugging it does not make any difference.   Also turning down/muting
the other inputs has no effect.

And yes it unfortunately sounds the same through mplayer.  (BTW, I had been using v1.07 
and mplayer would not play .nuv files at all.  After upgrading to the latest I only get sound.
Not really important since there's no need for it other than this test, however it's irritating 
to have something not working right)

I guess that narrows the problem down to something between the dsp and the actual
recording?  Is there an additional encoding step for the audio in there that could be borked?

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