audio: make softvol scale cubic

This brings the volume control closer to what is percepted as linear
volume change.

Adjust the --softvol-max default to roughly the old maximum (roughly
doubles the gain).

3 files changed, 13 insertions, 10 deletions

diff --git a/DOCS/man/options.rst b/DOCS/man/options.rst
index a0b59059b6..726376e1a9 100644
--- a/DOCS/man/options.rst
+++ b/DOCS/man/options.rst
@@ -890,7 +890,8 @@ Audio
     .. note::
 
         This was changed after the mpv 0.9 release. Before that, 100 actually
-        meant maximum volume.
+        meant maximum volume. At the same time, the volume scale was made cubic,
+        so the old values won't match up with the new ones anyway.
 
 ``--audio-delay=<sec>``
     Audio delay in seconds (positive or negative float value). Positive values
@@ -1059,10 +1060,9 @@ Audio
     their start timestamps differ, and then video timing is gradually adjusted
     if necessary to reach correct synchronization later.
 
-``--softvol-max=<100.0-10000.0>``
-    Set the maximum amplification level in percent (default: 200). A value of
-    200 will allow you to adjust the volume up to a maximum of double the
-    current level.
+``--softvol-max=<100.0-1000.0>``
+    Set the maximum amplification level in percent (default: 130). A value of
+    130 will allow you to adjust the volume up to about double the normal level.
 
 ``--audio-file-auto=<no|exact|fuzzy|all>``, ``--no-audio-file-auto``
     Load additional audio files matching the video filename. The parameter
diff --git a/audio/filter/af_volume.c b/audio/filter/af_volume.c
index a0b47e7438..dfdf586690 100644
--- a/audio/filter/af_volume.c
+++ b/audio/filter/af_volume.c
@@ -30,6 +30,7 @@
 #include "demux/demux.h"
 
 struct priv {
+    float vol;                  // User-specified non-linear volume
     float level;                // User-specified gain level for each channel
     float rgain;                // Replaygain level
     int rgain_track;            // Enable/disable track based replaygain
@@ -87,10 +88,12 @@ static int control(struct af_instance *af, int cmd, void *arg)
         return af_test_output(af, in);
     }
     case AF_CONTROL_SET_VOLUME:
-        s->level = *(float *)arg;
+        s->vol = *(float *)arg;
+        s->level = pow(s->vol, 3);
+        MP_VERBOSE(af, "volume gain: %f\n", s->level);
         return AF_OK;
     case AF_CONTROL_GET_VOLUME:
-        *(float *)arg = s->level;
+        *(float *)arg = s->vol;
         return AF_OK;
     }
     return AF_UNKNOWN;
diff --git a/options/options.c b/options/options.c
index dcd6167c4e..4c46c6f190 100644
--- a/options/options.c
+++ b/options/options.c
@@ -379,8 +379,8 @@ const m_option_t mp_opts[] = {
                ({"no", SOFTVOL_NO},
                 {"yes", SOFTVOL_YES},
                 {"auto", SOFTVOL_AUTO})),
-    OPT_FLOATRANGE("softvol-max", softvol_max, 0, 100, 10000),
-    OPT_FLOATRANGE("volume", mixer_init_volume, 0, -1, 10000),
+    OPT_FLOATRANGE("softvol-max", softvol_max, 0, 100, 1000),
+    OPT_FLOATRANGE("volume", mixer_init_volume, 0, -1, 1000),
     OPT_CHOICE("mute", mixer_init_mute, 0,
                ({"auto", -1},
                 {"no", 0},
@@ -644,7 +644,7 @@ const struct MPOpts mp_default_opts = {
     .video_decoders = NULL,
     .deinterlace = -1,
     .softvol = SOFTVOL_AUTO,
-    .softvol_max = 200,
+    .softvol_max = 130,
     .mixer_init_volume = -1,
     .mixer_init_mute = -1,
     .gapless_audio = -1,