[mythtv-users] volume control not working in mythtv 0.22 SVN trunk

[Michael T. Dean]

On 09/19/2009 12:47 AM, Clark Lee wrote:
> This should be a pretty old problem - I have searched internet and found quite a lot pages. However, I have tried them but neither worked for me.
>
> My system:pre-compile trunk r21831 on ubuntu 9.04. 
> A 7134 based caputer card which only has a composite input; to get video input from STB;
> Integrated sound: Audio input is connnect from the right/left sound output of STB;
> LiveTV, record, all works fine.
>
> --> The issue:
> in mythtv, when I push remote volume up and down, the Volume bar goes up and down, but the sound stays the same. Mute doesn't work either, while a 'mute on' 'mute off' is shown on screen.
>
> --> Tried the following one but still doesn't work
> Changing Mixer Device from /dev/mixer to ALSA:default fixed the problem
>
> --> external change script
> This seem a bit overkill to me... I don't need to control surrend sound, etc. Just Right/Left sound output.
>   

That's not just for controlling surround volume.

> There are two places related to the sound control setting, I believe:
> 1) mythtv-setup->capture card->Capture Card Setup
> Video Device: /dev/video0
> Audio Device: /dev/dsp (set to others. like dsp1, ro ALSA:default will not have any sound in mythtv)
>   

This is unrelated to playback volume control.  It's the recording volume.

> 2) myth-frontend->settings->general->
> Audio system:
> audio output device": "ALSA:default" but "/dev/dsp" doesn't maetter.
> Audio Mixer: 
> Use interal volumn ocntrols
> Mixer device: ALSA:default
> Mixer controls: Master/PCM doesn't affect it
>   

This is the type of thing that's related.

> Any idea on how to deal with it?

I'm guessing you're using digital audio output and have "Enable AC3 to 
SPDIF passthrough" and "Enable DTS to SPDIF passthrough" enabled.

If you're using the analog outputs of your sound card, then you're 
probably using a "High-definition" audio sound card that doesn't have a 
Master (and, if changing Mixer controls to PCM doesn't fix it, a PCM) 
volume control.  In this case, your only options (with ALSA or OSS audio 
output) are either to a) define a softvol control called Master or PCM 
or b) use an external volume-control script or c) get a different sound 
card.

http://www.gossamer-threads.com/lists/mythtv/users/216149#216149
http://www.gossamer-threads.com/lists/mythtv/users/320657#320657

Mike