[mythtv-users] STRANGE audio problems

Martin Moeller martin at martinm-76.dk
Sat Jun 19 04:11:21 EDT 2004

It sounds a bit like the problem I had when going to SuSE Linux 9.1

Two things for you to try. I have done both, maybe one is enough:

1) v4lctl volume 75% (or 85%, or...)
2) Get the latest video4linux snapshot from linux.bytesex.org and
compile that. You need to get your previous modules out of the way.
I described this in a post called:

[INFO] Getting the most out of your SAA7134 chip

It ought to apply to other popular chipsets also (with some differences
in modules, of course).

You may also want to force the norm of the signal through, e.g:

v4lctl setnorm PAL-BG (for America: v4lctl setnorm NTSC). Use v4lctl
list to see what options are available and their current value.

I tried setting my norm in the channel.tvformat row but that doesn't
seem to have made a difference unfortunately. I have yet to receive a
reply as to the purpose of the field if not this, so we'll see what

Should you get pure static at times, try forcing the norm again. It
works here. In fact I have made a script to check this every minute due
to mythtvs current inability to set the norm automatically after tuning
(at least on my system).

It looks as follows:


STATUS=$(/usr/X11R6/bin/v4lctl -c /dev/video0 list | grep norm | cut
-c23- | cut -d" " -f1)
if [ "$STATUS" != "PAL-BG" ] ; then
  /usr/X11R6/bin/v4lctl -c /dev/video0 setnorm PAL-BG
  mail -s "$(date) - Manually set PAL-BG" root << END
Something warped the detection again. It was set to : $STATUS.

If your norm is not PAL-BG, change that, naturally ;) - Also make sure
your video device is /dev/video0, etc.

This may or may not be the solution to your troubles, but theres a
pretty good chance it is. I have lost you original mail (speedy delete
finger) so I am not sure which capture card you're using...

lÝr, 2004-06-19 kl. 08:05 skrev Robert Goodkin:
> Narrowed down my problems a little more today.  Droped
> in an sb-live to replace my onboard AC'97 and replaced
> my TV card.  I'm still getting NASTY distortion when
> viewing TV/TV recordings.  When I use tvtime all is
> fine, but throuh capture ALSA is choking somehow. 
> Anyway to narrow this down?  I set the mixer levels
> according to the documentation.  I am using one of the
> newer versions of alsa 1.0.3 or something like that.
> Thanks,
> Bob
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