[MPlayer-dev-eng] [PATCH] forceable software volume control

[Ed Wildgoose]

>>I do agree that using a dB scale everywhere is a nice idea in theory, 
>>but it needs a careful implementation in practice.  I talked the 
>>bio2jack author into adding such a volume control to his Jack output 
>>layer and he immediately found that his volume control in XMMS then 
>>became just far too sensitive when trying to slide it a little with the 
>>mouse.  The linear was better in practice because he could get some 
>>control where it was needed, but still turn it really low if required.  
>>I guess a kind of "half" log measure would be ideal...  Perhaps less of 
>>    
>>
>
>wtf? half log? no, just use a smaller scale, e.g. 0.5 or 0.25 dB
>instead of 1 dB at a time. but i really doubt that's necessary..
>  
>

I was talking about the issue that usually the on screen display runs 
from 0-100.  This then has to map to some internal range (log scale in 
your design).  I persuaded the bio2jack author to experiment with using 
the 1-100 scale to mean number of of dB attenuated, and he found it very 
hard to control volume.  Same even with 40dB of range.

I was suggesting that actually something which was basically almost 
linear but moves a bit faster at the top end than the bottom end.  A 
very "low" exponential function basically.  For practical purposes where 
the volume control on the audio mixer is living near the top end of the 
scale usually, I think this offers the "best" solution.  However, if you 
are an example of someone who normally lives with the volume control 
turned down 15dB or more, and only occasionally cranks it up to maximum 
then this clearly isn't quite so helpful.

Do you see what I am getting at though?  It's a user interface issue, 
not a theoretical one.  I personally like the idea of a dB volume scale.

By the way, are you really throwing away a large chunk of your DAC's 
dynamic range most of the time?  Do you have no outboard volume control 
at all?  Just curious...

Ed W
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