On Thu, 10.06.10 17:11, Colin Guthrie (gmane@xxxxxxxxxxxxxx) wrote: > > 'Twas brillig, and Raymond Yau at 10/06/10 04:16 did gyre and gimble: > > Can you explain how PA handle the volume controls of ac97 codec ? > > > > PCM -34.5dB to +*12* dB > > Master -46.5dB to 0dB > > > > The total dB range (PCM + MASTER) is -81dB to +*12*dB > > > > > > Most user concern about recording without distrotion. (i.e. best result when > > Capture Volume at 0dB , PCM and Master Volume at 0dB ) and they need where > > are 0dB points > > I'm not 100% sure how this is handled, but I know it's not ignored. > You'll have to ask Lennart directly or dig in the code to see for sure. If the ALSA volume range is -x dB to +y dB, then the PA volume range will be -x-y dB to 0dB (i.e. shifted by -y dB). On top of that most volume controls should then mark the ALSA 0dB point as "base" volume on the slider, at what PA then calls -y dB. That way we will expose 0dB as maximum hw amplitude uniformly on all sound cards and have a special point on the slider that is hinted to be the "comfort" point. This is all explained on http://pulseaudio.org/wiki/WritingVolumeControlUIs#BaseVolumes Lennart -- Lennart Poettering Red Hat, Inc. lennart [at] poettering [dot] net http://0pointer.net/lennart/ GnuPG 0x1A015CC4 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
