[Usability] Mute in GNOME mixer applet does not have correct behavior

[Jaap Haitsma <jaap haitsma org>]

Hi,

Current behavior
----------------

There are 5 icons in GNOME to show the volume of an audio card

"stock_volume-mute": A speaker with a red X
"stock_volume-0": A speaker with no sound waves
"stock_volume-min": A speaker with one sound waves
"stock_volume-med": A speaker with two sound waves
"stock_volume-max": A speaker with three sound waves

The behavior of the mixer applet is the following:

volume(x)	Icon
----------------------
mute		mute
0		mute
0 < x < 1/3	low
1/3 <= x < 2/3	med
2/3 <= x < 1	max


The problem with mute
---------------------

If you have the volume set to zero you see the mute icon. If you then
use then press the mute/unmute button on your keyboard nothing seems to
happen. Actually the state goes from mute to 0, but because the icon
stays the same there is no visual feedback and the user is left
confused.

The solution
-------------

IMHO behavior should be the following
 
volume(x)	Icon
----------------------
mute		mute
0		0
0 < x < 1/3	low
1/3 <= x < 2/3	med
2/3 <= x < 1	max

This way a user will see a visual difference between volume 0 and mute
and thus the bug as explained before will not be present.

Furthermore behavior is identical to how a mute button works on normal
audio amplifiers.

I actually filed a patch for this a while ago [1], but the maintainers
argue that many sound cards do not have a mute and that applications
just set the volume to zero if they want to mute.

The good thing is that now more and more apps use gstreamer and
gstreamer hides the fact that some soundcards do not have a mute. I.e
gstreamer just makes it look like the card has a mute.

With my proposal applications that don't support gstreamer and use a
card without mute possibilities and thus simply set the volume to zero
will show the "stock_volume-0" icon. Which I think is not too bad as it
is clear to the user that he will not hear any audio.  

Conclusion
------------
What do the usability people think of this??

Jaap


[1] http://bugzilla.gnome.org/show_bug.cgi?id=164925