to_alsa_dB() returns a result rounded to two decimal places (instead of
using integer truncation) to avoid small errors when converting between
dB and volume.
Consider playback at -22 dB (which is supported by ALSA) but results in
the higher level of -21 dB plus software attenuation.
pa_sw_volume_from_dB(-22) = 28172
pa_sw_volume_to_dB(28172) = -21.9997351
to_alsa_dB(-21.9997351) = -2199
ALSA value 106 = -2200
ALSA value 107 = -2100
...
rounding = +1 /* "accurate or first above" */
snd_mixer_selem_ask_playback_dB_vol(me, -2199, rounding, &alsa_val)
alsa_val = -2100
Signed-off-by: Ian Ray <ian.ray@ge.com>
}
static long to_alsa_dB(pa_volume_t v) {
- return (long) (pa_sw_volume_to_dB(v) * 100.0);
+ return lround(pa_sw_volume_to_dB(v) * 100.0);
}
static pa_volume_t from_alsa_dB(long v) {