[mythtv-users] Odd audio issue (bt878 tuner, SB audigy2zs, FC7)
Bryan Thorne
bthorne at vt.edu
Fri Nov 9 15:15:32 UTC 2007
When forced to switch Mythtv to schedules direct, I took the opportunity
to upgrade my stable FC4 mythtv system to FC7 and the newest version of
MythTV. Since then, I have encountered this rather odd audio issue.
When watching live tv or recording using MythTV, I get no audio from my
tuner card unless Xawtv is also running in the background. If I start
mythtv and select watch live tv, for example, I get no audio. If I then
open a terminal and start xawtv, a few seconds later I get audio in sync
with Mythtv's video stream. If I close xawtv, the audio disappears
after a short delay. Running xawtv alone without mythtv produces no
audio, as I have the analog mix muted and capture from analog mix
selected. Aplay /dev/dsp produces the expected output (audio slightly
delayed from xawtv window, some underrun's). I have dealt with this for
the past few weeks by keeping xawtv running in the background on another
workspace, enabling mythtv to record properly, but I would like to avoid
doing this. Settings in alsamixer do not change on starting xawtv, and
a comparison of loaded modules from lsmod shows no differences between
mythtv running alone and mythtv running after starting xawtv. My best
guess is that xawtv is initializing something in the tv tuner card that
mythtv is not, but I have no idea what that would be or how to get
mythtv to do it. Any help would be appreciated, as I'm a bit confused.
System configuration is below. I can send any requested outputs this
afternoon on my return home from work.
Thanks for your assistance,
Bryan
Hardware config:
Sound card: sound blaster audigy 2 zs
Tuner card: Kworld KW-tv878fm
Video card: ATI Radeon x1600 pro (currently using vesa drivers for xorg,
but that's another story)
Processors: 2 AMD athlon mp2400+, tyan tiger motherboard
Software:
Fedora Core 7
Mythtv 0.20.2
modprobe.conf lines to initialize bt878 drivers (these were working
before my reinstall)
<code>
alias char-major-89 i2c-dev
options i2c-algo-bit bit_test=1
alias char-major-81 videodev
alias char-major-81-0 bttv
alias char-major-81-1 tvaudio
options bttv card=78 radio=1 pll=1 tuner=2
</code>
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