2 * A Simple ALSA Volume Control via OSD
4 * (c) 2012 Martin Mares <mj@ucw.cz>
13 #include <alsa/asoundlib.h>
17 static char *alsa_device = "default";
18 static char *mixer_control = "Master";
20 static int want_mute = -1;
22 static snd_mixer_t *mixer;
23 static snd_mixer_elem_t *elem;
25 static void init_mixer(void)
29 if (err = snd_mixer_open(&mixer, 0))
30 die("snd_mixer_open failed: error %d", err);
32 if (err = snd_mixer_attach(mixer, alsa_device))
33 die("snd_mixer_attach failed: error %d", err);
35 if (err = snd_mixer_selem_register(mixer, NULL, NULL))
36 die("snd_mixer_selem_register failed: error %d", err);
38 if (err = snd_mixer_load(mixer))
39 die("snd_mixer_load: error %d", err);
41 for (elem = snd_mixer_first_elem(mixer); elem; elem = snd_mixer_elem_next(elem))
43 const char *name = snd_mixer_selem_get_name(elem);
44 int index = snd_mixer_selem_get_index(elem);
45 if (!strcmp(name, mixer_control) || index)
47 if (snd_mixer_elem_get_type(elem) != SND_MIXER_ELEM_SIMPLE)
48 die("Unable to handle non-simple mixer controls");
49 if (!snd_mixer_selem_is_active(elem))
50 die("Selected mixer control is not active");
51 DBG("Found mixer control %s[%d]\n", name, index);
56 die("Unable to find mixer control %s", mixer_control);
59 static int get_mute(void)
61 int mute_on = 0, mute_off = 0;
63 if (snd_mixer_selem_has_playback_switch(elem))
65 for (snd_mixer_selem_channel_id_t ch=0; ch < SND_MIXER_SCHN_LAST; ch++)
68 if (snd_mixer_selem_get_playback_switch(elem, ch, &val))
77 DBG("Mute: on=%d off=%d\n", mute_on, mute_off);
81 static long get_volume(long *pmin, long *pmax)
83 long min, max, curr=0;
84 if (!snd_mixer_selem_has_playback_volume(elem) ||
85 snd_mixer_selem_get_playback_volume_range(elem, &min, &max))
91 for (snd_mixer_selem_channel_id_t ch=0; ch < SND_MIXER_SCHN_LAST; ch++)
94 if (snd_mixer_selem_get_playback_volume(elem, ch, &val))
101 DBG("Volume: min=%ld max=%ld curr=%ld\n", min, max, curr);
107 static int vol_to_perc(long curr, long min, long max)
109 return (100LL * (curr-min) + (max-min)/2) / (max-min);
112 static long perc_to_vol(int perc, long min, long max)
114 return ((long long) perc * (max-min) + 50) / 100;
117 static void show_mixer(void)
120 long curr = get_volume(&min, &max);
121 int muted = get_mute();
123 struct osd_msg *msg = osd_new_msg();
124 osd_add_line(msg, "min-duration", "0");
126 snprintf(buf, sizeof(buf), "%s volume", mixer_control);
127 osd_add_line(msg, NULL, buf);
128 osd_add_line(msg, NULL, "");
130 osd_add_line(msg, NULL, "[mute]");
133 snprintf(buf, sizeof(buf), "%d", vol_to_perc(curr, min, max));
134 osd_add_line(msg, "slider", buf);
140 static void set_mute(void)
146 want_mute = !get_mute();
148 if (snd_mixer_selem_has_playback_switch(elem))
150 for (snd_mixer_selem_channel_id_t ch=0; ch < SND_MIXER_SCHN_LAST; ch++)
151 snd_mixer_selem_set_playback_switch(elem, ch, !want_mute);
155 static void set_volume(void)
161 long curr = get_volume(&min, &max);
162 int perc = vol_to_perc(curr, min, max);
164 DBG("Volume: have %d %ld\n", perc, curr);
170 curr = perc_to_vol(perc, min, max);
171 curr = min + (((long long) perc * (max-min) + 50) / 100);
172 DBG("Volume: want %d %ld\n", perc, curr);
174 for (snd_mixer_selem_channel_id_t ch=0; ch < SND_MIXER_SCHN_LAST; ch++)
175 snd_mixer_selem_set_playback_volume(elem, ch, curr);
182 Usage: osd-alsa <options>\n\
185 -a, --adjust=<percent> Adjust the control by a given amount\n\
186 -D, --device=<name> ALSA device (default: `default')\n\
187 -m, --mixer=<name> Name of mixer control (default: `Master')\n\
188 -0, --mute Mute the control\n\
189 -t, --toggle Mute/unmute the control\n\
190 -1, --unmute Unmute the control\n\
195 static const char short_opts[] = "01a:c:D:t";
197 static const struct option long_opts[] = {
198 { "adjust", required_argument, NULL, 'a' },
199 { "device", required_argument, NULL, 'D' },
200 { "mixer", required_argument, NULL, 'm' },
201 { "mute", no_argument, NULL, '0' },
202 { "toggle", no_argument, NULL, 't' },
203 { "unmute", no_argument, NULL, '1' },
204 { NULL, 0, NULL, 0 },
207 int main(int argc, char **argv)
210 while ((opt = getopt_long(argc, argv, short_opts, long_opts, NULL)) >= 0)
220 adjust_by = atoi(optarg);
223 alsa_device = optarg;
226 mixer_control = optarg;