[mythtv-users] Mythsqueezebox Volume Control Doesn't Work

George Galt george.galt at gmail.com
Mon Mar 16 19:14:07 UTC 2009

On Mon, Mar 16, 2009 at 2:59 PM, Robert <RobertCL at iname.com> wrote:
> Robert wrote:
>> George Galt wrote:
>>> On Sun, Mar 15, 2009 at 5:22 PM, Robert <RobertCL at iname.com> wrote:
>>>> Hi,
>>>> I've managed to get the mythsqueezebox plugin compiled and working on
>>>> Gentoo.  All seems well, except the volume control doesn't actually
>>>> change
>>>> the volume.
>>>> I can "appear" to change the volume using either the volume buttons on
>>>> my
>>>> remote (I see the volume bar in mythsqueezebox move on-screen) or using
>>>> the
>>>> volume control from squeezecenter (web interface) but the actual volume
>>>> of
>>>> playback never changes.
>>>> I've looked in mythfrontend logs, but there are no obvious errors.  I'm
>>>> thinking of buying some squeezebox hardware, so I'd like to get this
>>>> working
>>>> so I can use it with that.
>>>> Where should I start looking?
>>>> (just to be clear, I do hear the music I've added to the playlist being
>>>> played, it's just that chaning the volume doesn't work)
>>>> Thanks,
>>>> Robert.
>>>> Mythtv-0.21_p19961 (-fixes?)
>>>> media-libs/portaudio-19_pre20071207
>>>> Linux version (root at quad) (gcc version 4.1.2 (Gentoo 4.1.2
>>>> p1.1))
>>>> _______________________________________________
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>>>> mythtv-users at mythtv.org
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>>> Robert:
>>> What output are you using?  It seems that somehow there is a conflict
>>> with how the plugin uses portaudio and using anything other than the
>>> standard "stereo" audio out on the soundcard (using something like the
>>> SPDIF out).  If this is the case, try using the standards "stereo" out
>>> for sound to see if this fixes it.  I'm not suggesting you leave it
>>> this way -- obviously, this is something that will have to be fixed.
>>> I've been considering dropping portaudio altogether, but it is a
>>> bigger project than I've got time for right now, so it will take some
>>> time.
>>> George
>> Hi,
>> MythTV is setup to use:
>>    Audio Output Device: ALSA:default
>>    Mixer Device: ALSA:default
>>    Mixer Controls: PCM
>> However, if I change to:
>>    Audio Output Device: /dev/pcm
>>    Mixer Device: /dev/mixer
>> Then volumne control doesn't work at all in Myth :-(  So I guess there is
>> some problem on my system as a whole in that /dev/mixer doesn't work
>> properly.
>> It looks like PortAudio is using OSS ??  So I'm guessing it's using
>> /dev/mixer by default and hence why it doesn't work.
>> So "all" I need to do is fix /dev/mixer....  Hmm.  I've never really got
>> to grips with alsa config, it's kind of just worked...
>> Robert.
> Ok, some success, I installed aumix to test the OSS mixer and noticed I
> didn't have a PCM device.
> I confirmed this by looking in /proc/asound/card0/oss_mixer which said 'PCM
> "" 0'.  So after some googling found that I should
>        echo 'PCM "PCM" 0' > /proc/asound/card0/oss_mixer
> Doing this made aumix show a PCM mixer (that works) and this seems to have
> made the volume control work in mythsqueezebox :-))
> So it all seems to be working ok.
> I hope you find time to develop this plugin further, because it seems like
> it would be a useful addition.
> Robert.
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Thanks for the information and for sticking with the plugin.  I'm sort
of holding off on further development until I can focus on a newer
version that works under the new MythUI structure in myth 0.22.  At
that time, I'm going to tackle a few outstanding issues -- such as the
use of portaudio.

FYI, you are correct that portaudio uses OSS as currently configured,
which is why I want to get away from it.


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