[pulseaudio-commits] Branch 'next' - src/modules

[Tanu Kaskinen]

 src/modules/alsa/alsa-mixer.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

New commits:
commit e84dc8b8989c81dfcdb71926f8abf4c38aa1a9b7
Author: Ian Ray <ian.ray at ge.com>
Date:   Wed Aug 30 11:09:48 2017 +0300

    alsa-mixer: round, not truncate, in to_alsa_dB
    
    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 at ge.com>

diff --git a/src/modules/alsa/alsa-mixer.c b/src/modules/alsa/alsa-mixer.c
index 3dbf6b1d..a7ad39dc 100644
--- a/src/modules/alsa/alsa-mixer.c
+++ b/src/modules/alsa/alsa-mixer.c
@@ -700,7 +700,7 @@ void pa_alsa_path_set_free(pa_alsa_path_set *ps) {
 }
 
 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) {