[LAD] Presenting volume control sliders

Lennart Poettering mzynq at 0pointer.de
Thu May 21 19:27:41 UTC 2009


I am currently working on the volume control handling of
PulseAudio. Until now the sliders in the UI mapped their position
linearly to the dB volume scale. i.e. if the slider is at '0%' we get
-90dB, if it is at '100%' we get 0dB, and between that we map linearly
from those percentages to the dB value. To be frank, this sucked big
time because the 'interesting' part is usually way up at -10dB to
0dB. and the remaining part of the volume sliders is pretty boring.

>From reading through the ALSA drivers I know that a lot of sound card
mixer controls usually have a much higher dB resolution near 0dB then
the have near -90dB. Most of the time the steps they choose are very
arbitrary however.

So, I was looking for better suggestions for mapping 'pixel
distances' in the UI to volume factors. I googled a bit and found this:


Which suggests a cubic relation between 'pixel distances' and the
linear factor. 

Any opinions on that? Other suggestions?



Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/           GnuPG 0x1A015CC4

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