Volume getter and setter behave inconsistently

[wiertz]

I am using mopidy as a backend to a music box project written in node js.

Problem: When using the alsamixer plugin, getting and setting volume behaves inconsistently: e.g. if I set the volume to a value of 50, I get a value of 49 on a subsequent check. This only happens with alsamixer, not with mopidy softwaremixer.

Expected behavior: setting the volume to 50 should yield a value of 50 on a subsequent get volume.

[kingosticks]

Sounds similar to #19

[wiertz]

The issue gets worse when using smaller volume steps as then volume changes are ignored (see #19). The fix for me is using the volume scale 'linear'.

Just a hunch, but perhaps there is something wrong with the assumptions of transforming volume into mixer values and vice versa? The readme of the alsamixer-plugin states that 'cubic' matches the volume scale used by the alsamixer software. Yet if I use linear, getting and setting volume work consistently – and every change is reflected by the alsamixer command line util. So if alsamixer software uses cubic and by using 'linear' in the plugin I can control alsamixer, why the additional transformation of volume values in mixer.py? Anyways, since the error I observe may very likely be the cause of #19, too, perhaps it makes sense to make 'linear' the default setting, at least for the time being.

[LevitatingBusinessMan]

I just want to add that incrementing and decrementing also makes for the same inconsistencies. For instance increasing the volume by 5% occasionally leads to a 4% increase.