[vlc-devel] [PATCH] auhal setMute (refs #7329)

[Rémi Denis-Courmont]

   Hello,

On Sunday 26 August 2012, Felix Paul Kühne wrote:
> > Also different outputs use different scales. ALSA would explode the
> > eardrums if it used a volume saved by PulseAudio.
> 
> Sure, that makes perfect sense. This why we had the 0 to 512 scale in VLC
> and left it as an implementation detail to the respective output module to
> do something useful with it and to respect the scale.

Respect what scale? The only thing the scale specifies is that 0 means mute and 
1 (previously 256) means 100%. It fails to say what 100% is. And it cannot be 
fixed. Ideally 100% should correspoind to a pair of voltage opposite levels on 
the analog line output corresponding to the two extreme pulse codes. However, 
I am yet to see any audio programming interface providing that data.

> This is not acceptable for me, since VLC would be the only media player on
> any platform I know, where you can only move the slider if an input is
> playing.

First, adjusting the volume level during silence is not normally possible. 
There is no feedback to appreciate the actual volume then.

Second, if the audio stream ends up being passed through digitally, a non-
functional volume control makes for a lot worse user experience than no or a 
greyed volume control.

-- 
Rémi Denis-Courmont
http://www.remlab.info