2010/4/9 Nicolo' Chieffo nicolo.chieffo@gmail.com
On Fri, Apr 9, 2010 at 1:11 AM, Raymond Yau superquad.vortex2@gmail.com wrote:
Mute Capable (1 bit) reports if the respective amplifier is capable of muting. Muting implies a –infinity gain (no sound passes), but the actual performance is determined by the hardware.
http://thread.gmane.org/gmane.linux.alsa.devel/39262/focus=16100
I think you missed the point, I'll explain again. I'm not complaining that at 0% the audio is not mute, as the bug you linked.
Clemens Ladisch (developer) 2004-11-09 09:26 The AD1981B's datasheet says that the maximum attenuation is 46.5 dB (which conforms to the AC'97 specification). To mute, use Mute.
In fact my problem is that at 0% I get mute, but I shouldn't (as reported by that developer), since the max attenuation is not -inf, but -48 dB. So if you prefer, you could see this issue from a different point of view: at -48 dB the audio should be still audible, but it's not.
so you have to decide where the issue resides (but definitely not in pulseaudio) a) it is ok that the audio is mute at 0% (in this case you have to declare -inf dB) b) the audio level is really -48 dB (in this case the volume shouldn't be cut off completely, but simply quite low) Which one do you prefer?
All the alsa drvier are using information in the codec datasheet to implement the dB scale
All the AC97 codec datasheet, DAC datahseet and HDA codec specifcation and datasheet are regarded the mute switch as -inf dB , the minimum dB are a finite negative number because the codec , DAC and HDA codec have finite bits of resolution when convert digital signal to analog signal
For your case if you change DAC amplifier volume control to -inf dB , how can you calculate the sum of Volume knob widget and DAC ampilifer volume control since the datasheet explicitly mention that the max atten is 95.25dB
may be pulseaudio did not add the volume knob widget in the calculation
I don't know how PA calculate the softvol plugin "PCM volume control" since you mention that PA seem not maintain "PCM volume control" at 0dB