Adding volume_mapping from alsa-utils/alsamixer
source: http://git.alsa-project.org/?p=alsa-utils.git;a=blob_plain;f=alsamixer/volume_mapping.c;hb=HEAD http://git.alsa-project.org/?p=alsa-utils.git;a=blob_plain;f=alsamixer/volume_mapping.h;hb=HEAD
This commit is contained in:
TermeHansen
Max Kellermann
parent
981dc0626b
commit
8a32ee30a5
@ -1386,6 +1386,7 @@ libmixer_plugins_a_SOURCES = \
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src/mixer/plugins/NullMixerPlugin.cxx \
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src/mixer/plugins/SoftwareMixerPlugin.cxx \
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src/mixer/plugins/SoftwareMixerPlugin.hxx
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libmixer_plugins_a_CPPFLAGS = $(AM_CPPFLAGS) \
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$(ALSA_CFLAGS) \
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$(PULSE_CFLAGS)
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@ -1394,7 +1395,10 @@ if ENABLE_ALSA
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liboutput_plugins_a_SOURCES += \
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src/output/plugins/AlsaOutputPlugin.cxx \
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src/output/plugins/AlsaOutputPlugin.hxx
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libmixer_plugins_a_SOURCES += src/mixer/plugins/AlsaMixerPlugin.cxx
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libmixer_plugins_a_SOURCES += \
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src/mixer/plugins/volume_mapping.h \
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src/mixer/plugins/volume_mapping.c \
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src/mixer/plugins/AlsaMixerPlugin.cxx
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endif
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if ANDROID
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180
src/mixer/plugins/volume_mapping.c
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180
src/mixer/plugins/volume_mapping.c
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@ -0,0 +1,180 @@
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/*
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* Copyright (c) 2010 Clemens Ladisch <clemens@ladisch.de>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* The functions in this file map the value ranges of ALSA mixer controls onto
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* the interval 0..1.
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*
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* The mapping is designed so that the position in the interval is proportional
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* to the volume as a human ear would perceive it (i.e., the position is the
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* cubic root of the linear sample multiplication factor). For controls with
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* a small range (24 dB or less), the mapping is linear in the dB values so
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* that each step has the same size visually. Only for controls without dB
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* information, a linear mapping of the hardware volume register values is used
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* (this is the same algorithm as used in the old alsamixer).
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*
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* When setting the volume, 'dir' is the rounding direction:
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* -1/0/1 = down/nearest/up.
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*/
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#include <math.h>
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#include <stdbool.h>
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#include "volume_mapping.h"
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#ifdef __UCLIBC__
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/* 10^x = 10^(log e^x) = (e^x)^log10 = e^(x * log 10) */
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#define exp10(x) (exp((x) * log(10)))
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#endif /* __UCLIBC__ */
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#define MAX_LINEAR_DB_SCALE 24
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static inline bool use_linear_dB_scale(long dBmin, long dBmax)
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{
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return dBmax - dBmin <= MAX_LINEAR_DB_SCALE * 100;
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}
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static long lrint_dir(double x, int dir)
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{
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if (dir > 0)
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return lrint(ceil(x));
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else if (dir < 0)
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return lrint(floor(x));
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else
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return lrint(x);
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}
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enum ctl_dir { PLAYBACK, CAPTURE };
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static int (* const get_dB_range[2])(snd_mixer_elem_t *, long *, long *) = {
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snd_mixer_selem_get_playback_dB_range,
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snd_mixer_selem_get_capture_dB_range,
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};
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static int (* const get_raw_range[2])(snd_mixer_elem_t *, long *, long *) = {
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snd_mixer_selem_get_playback_volume_range,
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snd_mixer_selem_get_capture_volume_range,
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};
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static int (* const get_dB[2])(snd_mixer_elem_t *, snd_mixer_selem_channel_id_t, long *) = {
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snd_mixer_selem_get_playback_dB,
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snd_mixer_selem_get_capture_dB,
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};
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static int (* const get_raw[2])(snd_mixer_elem_t *, snd_mixer_selem_channel_id_t, long *) = {
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snd_mixer_selem_get_playback_volume,
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snd_mixer_selem_get_capture_volume,
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};
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static int (* const set_dB[2])(snd_mixer_elem_t *, long, int) = {
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snd_mixer_selem_set_playback_dB_all,
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snd_mixer_selem_set_capture_dB_all,
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};
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static int (* const set_raw[2])(snd_mixer_elem_t *, long) = {
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snd_mixer_selem_set_playback_volume_all,
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snd_mixer_selem_set_capture_volume_all,
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};
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static double get_normalized_volume(snd_mixer_elem_t *elem,
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snd_mixer_selem_channel_id_t channel,
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enum ctl_dir ctl_dir)
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{
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long min, max, value;
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double normalized, min_norm;
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int err;
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err = get_dB_range[ctl_dir](elem, &min, &max);
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if (err < 0 || min >= max) {
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err = get_raw_range[ctl_dir](elem, &min, &max);
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if (err < 0 || min == max)
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return 0;
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err = get_raw[ctl_dir](elem, channel, &value);
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if (err < 0)
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return 0;
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return (value - min) / (double)(max - min);
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}
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err = get_dB[ctl_dir](elem, channel, &value);
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if (err < 0)
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return 0;
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if (use_linear_dB_scale(min, max))
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return (value - min) / (double)(max - min);
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normalized = exp10((value - max) / 6000.0);
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if (min != SND_CTL_TLV_DB_GAIN_MUTE) {
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min_norm = exp10((min - max) / 6000.0);
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normalized = (normalized - min_norm) / (1 - min_norm);
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}
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return normalized;
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}
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static int set_normalized_volume(snd_mixer_elem_t *elem,
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double volume,
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int dir,
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enum ctl_dir ctl_dir)
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{
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long min, max, value;
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double min_norm;
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int err;
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err = get_dB_range[ctl_dir](elem, &min, &max);
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if (err < 0 || min >= max) {
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err = get_raw_range[ctl_dir](elem, &min, &max);
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if (err < 0)
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return err;
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value = lrint_dir(volume * (max - min), dir) + min;
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return set_raw[ctl_dir](elem, value);
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}
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if (use_linear_dB_scale(min, max)) {
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value = lrint_dir(volume * (max - min), dir) + min;
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return set_dB[ctl_dir](elem, value, dir);
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}
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if (min != SND_CTL_TLV_DB_GAIN_MUTE) {
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min_norm = exp10((min - max) / 6000.0);
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volume = volume * (1 - min_norm) + min_norm;
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}
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value = lrint_dir(6000.0 * log10(volume), dir) + max;
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return set_dB[ctl_dir](elem, value, dir);
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}
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double get_normalized_playback_volume(snd_mixer_elem_t *elem,
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snd_mixer_selem_channel_id_t channel)
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{
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return get_normalized_volume(elem, channel, PLAYBACK);
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}
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double get_normalized_capture_volume(snd_mixer_elem_t *elem,
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snd_mixer_selem_channel_id_t channel)
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{
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return get_normalized_volume(elem, channel, CAPTURE);
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}
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int set_normalized_playback_volume(snd_mixer_elem_t *elem,
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double volume,
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int dir)
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{
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return set_normalized_volume(elem, volume, dir, PLAYBACK);
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}
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int set_normalized_capture_volume(snd_mixer_elem_t *elem,
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double volume,
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int dir)
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{
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return set_normalized_volume(elem, volume, dir, CAPTURE);
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}
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17
src/mixer/plugins/volume_mapping.h
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17
src/mixer/plugins/volume_mapping.h
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@ -0,0 +1,17 @@
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#ifndef VOLUME_MAPPING_H_INCLUDED
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#define VOLUME_MAPPING_H_INCLUDED
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#include <alsa/asoundlib.h>
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double get_normalized_playback_volume(snd_mixer_elem_t *elem,
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snd_mixer_selem_channel_id_t channel);
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double get_normalized_capture_volume(snd_mixer_elem_t *elem,
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snd_mixer_selem_channel_id_t channel);
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int set_normalized_playback_volume(snd_mixer_elem_t *elem,
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double volume,
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int dir);
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int set_normalized_capture_volume(snd_mixer_elem_t *elem,
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double volume,
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int dir);
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#endif
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