[mythtv-users] White noise on Myth recordings, but not on LiveTV or /dev/video0 > file

[Andy Flach]

My problem is that I can record video with good audio from the command
line (cat /dev/video0 > test.mpg), but every recording scheduled
through Myth has roaring white noise on the audio, with just a hint of
the dialog barely discernable through the roar.

Oddly, Live TV
has fine sound quality, except if you start it right after a scheduled
recording, in which case there is the static noise.  However, changing
to another channel clears up the noise, and then you can change back to
the channel that was originally noisy and the sound is perfect, and all
other channels have good audio.

If I schedule a recording of an
ongoing show on channel 6 (for example) through Myth, then stop the
recording, then run cat /dev/video0 > test.mpg from the command
line, the resulting video has the noisy static.  However, if I then run
ivtv-tune -c6 (the same channel) and then redo cat /dev/video0 >
test. mpg the sound on the resulting video is fine.

Clearly when the Myth backend accesses the capture card it is setting something incorrectly, but I have no idea what.

I
have run ivtvctl -a > file after both a noisy recording and after a
good recording, and there is no difference at all between the two. 
Doing dmesg | grep ivtv shows everything loading normally (at least to
my noob eyes).

I have tried upgrading to the latest ivtv version
for my kernel and that doesn't help.  I have tried changing all kinds
of things in the mythtv-setup and nothing seems to help.

I have tried doing recordings using the LiveTV profile, but that doesn't help.

Any ideas for what to try next, or what other information to post, would be greatly appreciated.  Here is my setup:

-Frontend/backend
installation of MythTV v0.20 from Edgy Eft repositories on a via epia
sp8000e running Ubuntu Edgy Eft installed from the alternate CD.
-PVR-150
-v0.7.4 ivtv

Thanks in advance.

Andy




 
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