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

[Remco Treffkorn]

On Monday 19 February 2007, Andy Flach wrote:
> 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

Google for "pvr 150 tinny audio".
Things have changed over the last few months, so go with the most recent 
suggestions. 

Cheers,
Remco
-- 
Remco Treffkorn (RT445)
HAM DC2XT
remco at rvt.com   (831) 685-1201