'Splain please re: mixer, alsa, pulseaudio and tvtime??

[William Case]

Hi Mikkel;

There is probably no need to reply to this post -- unless you see
something obviously wrong.  I am just posting to get the results on the
record -- so to speak.

On Fri, 2009-07-24 at 20:10 -0500, Mikkel L. Ellertson wrote:
> William Case wrote:
> > 
> > The question is more complex than that.  TVTime now has two mixer
> > options: OSS and Alsa.  The OSS channel names correspond to a list
> > supplied by tvtime.xml and to the list in alsamixer.  For Alsa I have
> > two choices of protocol or formulations to define the mixer and channel
> > used, either a)<option name="MixerDevice" value="default/Line"/> or b)
> > <option name="MixerDevice" value=<DEVICE[:CH]".  On my machine tvtime
> > seems to accept b) only.
> > 
> > I have only been able to find "Line" or "CD" suggested as possible
> > channels [:CH] for the alsa formulation.  Note the intial letter
> > capitalization of the channel name in Alsa versus the all lower case in
> > OSS.
> > 
> > So, can I use the same channel names, with a capitalized first letter,
> > as are listed for OSS or is there a new list of channel names that only
> > applies to Alsa?
> > 
> > The second part of the question I was asking was what channels do I want
> > to choose.  I have a lot of info here about what each of the channels is
> > *supposed* to do.  But I have received so much conflicting advice, and
> > tried so many possible combinations, I wanted to start fresh being able
> > to think through for myself what the settings should be.  The various
> > guis I have all seem to confuse the issue(s) rather than clarify.  The
> > fact that I have a PCIe bus with internal sound seems to greatly confuse
> > the issue and outdates much of the google information I have found.
> > 
> > In the end, this all may be a bug caused by faulty or outdated drivers.
> > But first I would like to work my way through to a solid conclusion
> > before being castigated by maintainers for not knowing what I am talking
> > about.
> > 

> Ok let me define a couple of things. You may want to run
> "man amixer" for a full explanation.
> 
Although I have read 'man amixer' in the past, in conjunction with your
explanations, it now makes more sense.

> amixer info - provides information about the default card.
]$ amixer info
Card default 'pulse'/'PulseAudio'
  Mixer name	: 'PulseAudio'
  Components	: ''
  Controls      : 4
  Simple ctrls  : 2

I tried all 4 of the control names over a month ago and got no sound
from using any of them with alsamixer and/or Advanced Volume Control
[Device: HDA Intel (AlsaMixer)].  see below.

> -----------------------------------------------------------
> amixer scontrols - provides names of the controls for choice a.
> Simple mixer control 'Line',0
> would be channel "Line"
> 
$ amixer scontrols
Simple mixer control 'Master',0
Simple mixer control 'Capture',0

> -----------------------------------------------------------
> amixer scontrols - provides names of the controls for the f
> amixer controls - provides number/description for choice b.
> 
> numid=19,iface=MIXER,name='Line Playback Volume'
> would be channel 19.

]$ amixer controls
numid=4,iface=MIXER,name='Master Playback Switch'
numid=3,iface=MIXER,name='Master Playback Volume'
numid=2,iface=MIXER,name='Capture Switch'
numid=1,iface=MIXER,name='Capture Volume'

Set ]$ tvtime --mixer="hw:0/Master"
Tried Advanced Volume Control set to [Device: Playback: Internal Audio
(PulseAudio Mixer)] which showed only the 'Master' slider.

TVTime had no sound.  But at least responded visually to the +/- sound
keys.  However volume setting returned to 0 on each restart.

Set tvtime --mixer="hw:0/Front"
Tried Advanced Volume Control set to [Device: Playback: Internal Audio
(PulseAudio Mixer)]
Got no sound, but did get the volume settings retained for each start.

I then tried the pavucontrol gui configured to 'Profile: Output Analog
Stereo + Input Analog Stereo'.  The other options I had in the drop down
list were various combinations of Input, Output; Stereo, Surround;
Analog, Digital and IEC958. 

The Profile I choose, 'Output Analog Stereo + Input Analog Stereo', gave
me the most detail under the Playback, Output Devices and Input Devices
tabs.  In fact, when using RhythmBox, Playback and Output Devices tabs
showed the application name and a sound activity bar.  Similarly, when
playing a video on CNN, Playback showed 'ALSA plug-in [firefox]' and
sound activity.

However, when using tvtime no application is recognized by pavucontrol.
Except that under the Input Devices tab, the sound activity bar jiggles
a bit, as if trying to come to life.
> -----------------------------------------------------------
> amixer contents - gives much more information about the controls
>                   and the type of settings. It may help decide what
>                   control to use.

$ amixer contents
numid=4,iface=MIXER,name='Master Playback Switch'
  ; type=BOOLEAN,access=rw------,values=1
  : values=on
numid=3,iface=MIXER,name='Master Playback Volume'
  ; type=INTEGER,access=rw------,values=2,min=0,max=65536,step=1
  : values=57583,57583
numid=2,iface=MIXER,name='Capture Switch'
  ; type=BOOLEAN,access=rw------,values=1
  : values=on
numid=1,iface=MIXER,name='Capture Volume'
  ; type=INTEGER,access=rw------,values=2,min=0,max=65536,step=1
  : values=65536,65536

This too suggests I should use 'Master' as the tvtime control/channel.
And yet, 'Front' seems to produce better soundless results -- such as
they are.
> -----------------------------------------------------------
> aplay -l - lists the audio output cards in the system.
> 
]$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Intel [HDA Intel], device 0: ALC883 Analog [ALC883 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: Intel [HDA Intel], device 1: ALC883 Digital [ALC883 Digital]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

> Now, amixer defaults to sound card 0 (hw:0), but it can show other
> sound cards using the -c option (-c n). 

No combination of amixer and -c1 produces anything useful other than the
standard help list on stdout/stderr.

> If your TV card is like
> mine, and has a external cable between it and the sound card, then
> you are probably going to be using someting like the Line channel.
> 

My card does NOT have an external line.  'pavucontrol' seems to
recognize that by making reference to 'Internal Audio' only.

> On the other hand, you probably also have controls on your TV card
> as well. For me it is sound card 1, but I normally leave the
> controls at max. I also have a mixer page for it in the Gnome mixer.

I have no reference to my TV (tuner) card.  Amixer doesn't recognize
card1 or hw1.  Gnome mixer, Advanced Volume Control or pavucontrol don't
recognize it either, that I can see.
> 
> Both amixer and aplay are part of the ALSA package.
> 

I have been working on this for the last four hours.  I must say with
your notes and man and other on-line advice, I am beginning to re-gain
confidence that I haven't just screwed up in my choice of settings.

Those are the kind of words that get ya' killed -- oh well!

-- 
Regards Bill
Fedora 11, Gnome 2.26.3
Evo.2.26.3, Emacs 22.3.1