[alsa-devel] Mixer volume/decibel mapping

[Raymond Yau]

2010/5/25 James Courtier-Dutton <james.dutton at gmail.com>

>
>
> Could this maybe explain why pulseaudio was having such problems with
> alsa with regards to gain controls????
>

I don't think so since no soc user report wrong dB range

http://www.pulseaudio.org/wiki/WritingVolumeControlUIs

If the flat volume model of PA is  0% to 150% , this mean that alsa-lib does
not provide any DB scale suitable for PA to implement dB info for the pulse
device as DB_LINEAR require max is 0dB ( at least capture stream must have
gain )

only one of the PA developer complain about his HDA codec has incorrect dB
range but not willing to provide alsa-info.sh

There is a patch which may affect the dB scale

http://git.alsa-project.org/?p=alsa-kernel.git;a=commitdiff;h=7c7767ebe2fa847c91a0dd5551ca422aba359473;hp=29fdbec2dcb1ce364812778271056aa9516ff3ed