[mythtv-users] bttv audio (tvaudio) too load

papenfuss at juneau.me.vt.edu papenfuss at juneau.me.vt.edu
Tue Nov 25 08:11:11 EST 2003


On Tue, 25 Nov 2003, Jelle Kalf wrote:

> --- cut ---
>         The v4l bttv works OK, but the audio coming from it in mythtv is
> clipped badly.  I first figured the mixer (SBlive), adjustments didn't help.
> 
> I figured perhaps it was the stock OSS drivers, even with ALSA, no joy.  I
> have since figured out that it's a v4lctl volume function causing the
> problem.  If I decrease it with 'v4lctl volume 32768' (which is 50%), it's
> OK with xawtv, gv4l, etc.  Mythtv resets this to something more like 80%,
> which clips the input to the soundcard.  Any suggestions?
> --- /cut ---
> 
> Ehm, in mythfrontend  you can go to TV, Settings, recording profiles and set
> the input volume as far as I know ;)
> 
> I think this might help you a lot.
> 
	I just looked again to make sure I wasn't insane, but there is no
option to set the input volume in the Settings/TV Settings/Recording profiles
section.  The closest I've found is a gain control in 
Settings/General/Audio, but it only changes the mixer volumes.  The 
volume that's causing the problem is the v4l low-level card setting, not the 
mixer.  In other words, putting *all* the mixer settings at something really 
low like 10% doesn't fix the clipping.  The input signal (output from the 
capture card) is just too high.

Thoughts?  Is this gain setting hardcoded in mythtv at compile-time?  Just for 
the record, the version I'm running of mythtv is vanilla rpm:

$ rpm -qa | grep myth
mythvideo-0.12-32.rh9.at
mythweb-0.12-36.rh9.at
mythnews-0.12-6.rh9.at
mythtv-backend-0.12-46.rh9.at
mythtv-theme-visor-0.20030711-1.rh9.at
mythdvd-0.12-14.rh9.at
mythmkmovie-1.0.1-3.rh9.at
mythweather-0.12-33.rh9.at
mythtv-suite-0.12-34.rh9.at
mythtv-0.12-46.rh9.at
mythgame-0.12-35.rh9.at
mythmusic-0.12-36.rh9.at
mythtv-theme-photo-4-4.rh9.at
libmyth-0.12-46.rh9.at
mythgallery-0.12-36.rh9.at
mythtv-theme-purplegalaxy-0.20030623-2.rh9.at
mythtv-frontend-0.12-46.rh9.at


Thanks though.... :)

-Cory

-- 
*************************************************************************
* The prime directive of Linux:  					*
* 	- learn what you don't know, 					*
* 	- teach what you do.						*
* 						(Just my 20 USm$)	*
*************************************************************************




More information about the mythtv-users mailing list