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

[Michael Schwendt]

On Sat, 25 Jul 2009 01:49:06 -0400, William wrote:

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

This is with PulseAudio running, however, and therefore differs very much
from native ALSA without PulseAudio running. That adds another level on
top of ALSA. If you keep PulseAudio running, you rely on PulseAudio to get
several things right, and you cannot influence it since PulseAudio adds
itself as another layer on top of ALSA. Hence you see a "pulse" device
instead of the "default" (hw:0) device, for example. Same for input.

> I then tried the pavucontrol gui configured to 'Profile: Output Analog
> Stereo + Input Analog Stereo'.

Input Analog Stereo to me means it refers to Microphone and Line input
jacks which are connected with your onboard audio chipset. Unless somebody
disagress, that is the operation mode where you would need to place an
audio cable between tv card and input jack. Unlike digital input.

> 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.

Again, that is because tvtime doesn't do any audio playback at all.

> $ 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.

Can't follow that conclusion. 'Master' controls the final volume
of the sum of all active channels. It doesn't control which capture
channel is active and whether its volume is levelled up at all.
It also doesn't control whether any signal is sent to an input
channel (in analogue mode).

> > 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.

You don't have a device '1'. Your onboard chipset is the only one, '0'.