[mythtv-users] Help with volume control in mythtv

[Michael T. Dean]

On 03/04/2008 11:04 PM, sdkovacs wrote:

>  On Tue, Feb 19, 2008 at 12:28 PM, David Brieck Jr. wrote:
>
> > On Feb 19, 2008 11:42 AM, Chris Everest wrote:
> >
> >> if you are using /dev/dsp as your audio device, you can specify
> >> "Headphone" in your "Mixer Controls" field by simply typing it
> >> in.  In my experience can be the string label that alsamixer
> >> uses.
> >
> > I second this one. I had to manually type in the name in the mixer
> > control area to get mine to work correctly.
>
>  I tried that previously, and tried it again tonight. I'm including a
>  link to a screenshot to make sure that we talking about the same
>  setting. Again, the 'Headphone' mixer device is the only one that
>  truly controls volume, but mythtv seems to only change the volume on
>  the PCM device, regardless of what is in Mixer Controls.
>
>  Please see: http://i27.tinypic.com/ienz2x.jpg

The only supported values in Myth (at least with OSS or ALSA) are Master 
and PCM.  The code checks to see if the value is Master, and, if not, 
uses PCM.  So, anything you type in is nothing more than a placebo.

To solve your problem, you have 3 options:
    1) Since your sound card does not have a 'Master' control, you can 
actually define a softvol control named 'Master' using the ALSA 
configuration file (~/.asoundrc or /etc/asound.conf), then use this to 
change the volume.  Doing so has all the down sides of using a software 
volume control.
    2) You can disable "Use internal volume controls" and use an 
external script to control volume.
    3) You can get a different sound card.

(There is a 4--write a patch--but I'll leave it out of the list.  If, 
however, you want to do that, let me know as there are a few people you 
should probably talk to first (some who have plans for where the MythTV 
ALSA/OSS code will be going in the future).)

Mike