[mythtv-users] Creative Audigy LS: please help to setup volume control to work from Myth

[Michael T. Dean]

On 11/30/2007 02:23 AM, Andrew Junev wrote:
> Friday, November 30, 2007, 10:21:16 AM, you wrote:
>> Friday, November 30, 2007, 4:06:07 AM, you wrote:
>>> On 11/29/2007 03:05 PM, Andrew Junev wrote:
>>>       
>>>> I can't control LiveTV (or recordings) volume via MythTV. When
>>>> pressing '[' and ']' I can actually see the volume slider moving, but
>>>> the loudness itself does not change. It looks like it has something to
>>>> do with my Myth configuration, since I can control the volume via
>>>> alsamixer just fine.
>>> amixer scontrols
>>> output, please.
>> Here it is:
> ... and the scontrols output:
>
> # amixer scontrols
> Simple mixer control 'Line in',0
> Simple mixer control 'Mic',0
> Simple mixer control 'Phone',0
> Simple mixer control 'IEC958',0
> Simple mixer control 'IEC958 Center/LFE',0
> Simple mixer control 'IEC958 Front',0
> Simple mixer control 'IEC958 Rear',0
> Simple mixer control 'IEC958 Unknown',0
> Simple mixer control 'Aux',0
> Simple mixer control 'Analog Center/LFE',0
> Simple mixer control 'Analog Front',0
> Simple mixer control 'Analog Rear',0
> Simple mixer control 'Analog Side',0
> Simple mixer control 'Analog Source',0
> Simple mixer control 'CAPTURE feedback',0
> Simple mixer control 'Digital Source',0
> Simple mixer control 'Shared Mic/Line in',0

You have no Master control, and Myth kind of requires one for internal
volume control.  That means you have 2 options.  The first is to use an
external volume control script and disable "Use internal volume
controls" in Myth.  With this approach you lose the nice OSD, though. 
(I do have a script that does volume control and gives a poor-man's OSD
and a 90%-complete new project that could be integrated into the script
to give a more-robust poor-man's OSD.  However, since you have another
option...)

Normally, it's impossible to make Myth use a softvol volume
control--because Myth can only use Master and PCM and it's impossible to
redefine already existing hardware Master/PCM controls.  However, since
your card is actually missing Master/PCM controls, you can define
softvol control called Master (can't re-define, but since there is none,
defining one is not redefining).  Then change Myth's "Mixer controls"
setting to Master.  You'll need to define the control using the ALSA
config file, ~/.asoundrc or /etc/asound.conf, and you must call it
Master (since Myth needs a Master control).

There are a lot of good references on the 'net about creating softvol
controls.

Mike