At Fri, 9 Mar 2012 18:06:17 +0800, Adam Lee wrote:

On Fri, Mar 09, 2012 at 10:30:27AM +0100, Takashi Iwai wrote:

...

At Fri, 9 Mar 2012 17:07:17 +0800, Adam Lee wrote:

...

On Fri, Mar 09, 2012 at 07:40:27AM +0100, Takashi Iwai wrote:

...

At Fri, 9 Mar 2012 12:22:47 +0800, Adam Lee wrote:

...

Add Vincent in cc, because conky read amixer's result.

On Thu, Mar 08, 2012 at 05:45:14PM +0100, Takashi Iwai wrote:

...

> * Adam Lee adam8157@gmail.com [2012-03-08 20:36 +0800]: > > Package: alsa-utils > Version: 1.0.25-1 > Severity: important > > > db is not linear, but amixer believe it is. > > "amixer get Master" says "Limits: Playback 0 - 74", then everytime I run > "amixer -q sset Master 10%-", there is 8db dec. > > For example, at first Master is 100% and 0db, both alsamixer and amixer > think it is, and after I run "amixer -q sset Master 10%-", both > alsamixer and amixer says Master is -8.00db, but alsamixer says it is > 72%, amixer says it is 89%. > > alsamixer is right, amixer calc and set wrongly.

No, both are correct. You are dreaming too much on the world unified percentage representation :)

The percentage in amixer has nothing to do with dB level. It's just the percentage of the raw value range of that mixer element. Thus showing 89% is correct. It's 10% down from 100% (1% is because of the resolution of the raw values).

Now, alsamixer shows the percentage in a different way. It's explained well in the source code (alsamixer/volume_mapping.c), but not mentioned in the man page, unfortunately.

• The mapping is designed so that the position in the interval is proportional
• to the volume as a human ear would perceive it (i.e., the position is the
• cubic root of the linear sample multiplication factor). For controls with
• a small range (24 dB or less), the mapping is linear in the dB values so
• that each step has the same size visually. Only for controls without dB
• information, a linear mapping of the hardware volume register values is used
• (this is the same algorithm as used in the old alsamixer).

The percentage representation in alsamixer corresponds to this mapping, thus it's neither dB nor linear percent.

Hi, Takashi

Thank you for replying. But I still insist this is a bug. Three questions:

1, several months ago, it's OK, both amixer and alsamixer use the human mapping(0-10% and 90%-100% are the same change by a human ear), why not now?

amixer hasn't been changed until yet. It handles either in raw values or in dB. No human-ear mapping at all. It's never changed since years, and won't be changed. If the volume mapping would be implemented to amixer in future, it must be only optional.

Only the recent alsamixer introduced the volume mapping to visualize the volumes reasonably.

OK, thank you. Maybe an optional will make everyone happy.

...

...

2, conky(Vincent, I mean ${mixer}), some other software, lot of user's scripts use amixer to set or get volume, expecting the human mapping, why change the behavior?

You must be smoking something bad. The behavior of amixer hasn't been changed.

I figured out a reason probably, when the limits range is wide, like 0-65536, amixer's mapping and alsamixer's human-ear mapping are close.

If I remember right, my hardware's limits was 0-65536, but it becomes 0-74 after I run "alsactl init", but unfortunately, I don't know how to modify it back.

...

...

3, alsamixer and amixer use the same dB value, why there is difference in percentage? If alsa-utils developer think the human mapping sucks, why you guys still use it in alsamixer? There is no "both correct", the difference confuses user...

That's true. alsamixer should have stopped showing the stupid percentage.

The biggest understand is that people (including you) think there is an absolutely perfect percentage definition for the sound level. It's an illusion.

I don't expect an absolutely perfect percentage definition. I want a human-ear mapping, which alsamixer does well, 100% is about as ten times loud as 10%.

How did you measure _quantitatively_ it's exactly ten times louder? And you think 50% is ten times loud as 5% volume, 10% is ten times loud as 1%? Things aren't so easy, unfortunately.

...

But amixer doesn't work like that, amixer's 100% is about as *one hundred times* as amixer's 10%.

Yes, this is what's amixer expected to behave. It's a value just representing the percentage of a "raw value" of the mixer element. It never says it's corresponding to any practical volume. This is the misunderstanding first of all.

For example, I guess in your 64k case, the raw value is even not in dB unit but it's a linear volume. amixer doesn't care. 10% means only the 6553 of 65536. That's all. So simple. (In addition, amixer can handle dB, e.g. amixer set Master +10dB or such. But it's not suitable for percentage unit because dB level can't be represented in the absolute percent volume -- what is 10% in dB?)

...

Maybe it is beautiful, and alsamixer's human-ear mapping is stupid in the sound science universe. But as a common user, I don't think so. And I don't know how you guys put up with it :(

No, you misunderstand what I wrote. alsamixer's mapping is really an improvement. That's why it was implemented recently. But if it shows a different number, user may wonder, just like you did. If you didn't see a number, you didn't notice the difference :)

But amixer wasn't changed. amixer is a tool to manipulate raw values. Of course, it'd be also nice to implement the same percentage expression, but as already mentioned, it should be activated only via an option. The default behavior of amixer must not be changed for compatibility reason.

OK.

Looking forward to the option, if your time and other capacity allow :)

The implementation isn't too hard. I wrote a quick patch now as below. It became bigger than I thought since it contains many clean-ups that are needed to adapt the mapped volume.

With the patch, amixer shows and reads the percent value with -M option just like in alsamixer.

Takashi

--- diff --git a/amixer/Makefile.am b/amixer/Makefile.am index fcd0e81..ba67a57 100644 --- a/amixer/Makefile.am +++ b/amixer/Makefile.am @@ -4,7 +4,7 @@ LDADD = -lm # CFLAGS += -g -Wall

bin_PROGRAMS = amixer -amixer_SOURCES = amixer.c +amixer_SOURCES = amixer.c ../alsamixer/volume_mapping.c noinst_HEADERS = amixer.h man_MANS = amixer.1 EXTRA_DIST = amixer.1 diff --git a/amixer/amixer.c b/amixer/amixer.c index 9d2855d..a0a7387 100644 --- a/amixer/amixer.c +++ b/amixer/amixer.c @@ -29,7 +29,9 @@ #include <assert.h> #include <alsa/asoundlib.h> #include <sys/poll.h> +#include <stdint.h> #include "amixer.h" +#include "../alsamixer/volume_mapping.h"

#define LEVEL_BASIC (1<<0) #define LEVEL_INACTIVE (1<<1) @@ -68,6 +70,8 @@ static int help(void) printf(" -i,--inactive show also inactive controls\n"); printf(" -a,--abstract L select abstraction level (none or basic)\n"); printf(" -s,--stdin Read and execute commands from stdin sequentially\n"); + printf(" -R,--raw-volume Use the raw value (default)\n"); + printf(" -M,--mapped-volume Use the mapped volume\n"); printf("\nAvailable commands:\n"); printf(" scontrols show all mixer simple controls\n"); printf(" scontents show contents of all mixer simple controls (default command)\n"); @@ -187,9 +191,9 @@ static int convert_db_range(int val, int omin, int omax, int nmin, int nmax)

/* Fuction to convert from volume to percentage. val = volume */

-static int convert_prange(int val, int min, int max) +static int convert_prange(long val, long min, long max) { - int range = max - min; + long range = max - min; int tmp;

if (range == 0) @@ -204,29 +208,6 @@ static int convert_prange(int val, int min, int max) #define convert_prange1(val, min, max) \ ceil((val) * ((max) - (min)) * 0.01 + (min))

-static const char *get_percent(int val, int min, int max) -{ - static char str[32]; - int p; - - p = convert_prange(val, min, max); - sprintf(str, "%i [%i%%]", val, p); - return str; -} - -#if 0 -static const char *get_percent1(int val, int min, int max, int min_dB, int max_dB) -{ - static char str[32]; - int p, db; - - p = convert_prange(val, min, max); - db = convert_db_range(val, min, max, min_dB, max_dB); - sprintf(str, "%i [%i%%] [%i.%02idB]", val, p, db / 100, abs(db % 100)); - return str; -} -#endif - static long get_integer(char **ptr, long min, long max) { long val = min; @@ -288,26 +269,83 @@ struct volume_ops { int (*get)(snd_mixer_elem_t *elem, snd_mixer_selem_channel_id_t c, long *value); int (*set)(snd_mixer_elem_t *elem, snd_mixer_selem_channel_id_t c, - long value); + long value, int dir); }; -enum { VOL_RAW, VOL_DB }; +enum { VOL_RAW, VOL_DB, VOL_MAP };

struct volume_ops_set { int (*has_volume)(snd_mixer_elem_t *elem); - struct volume_ops v[2]; + struct volume_ops v[3]; };

static int set_playback_dB(snd_mixer_elem_t *elem, - snd_mixer_selem_channel_id_t c, long value) + snd_mixer_selem_channel_id_t c, long value, int dir) { - return snd_mixer_selem_set_playback_dB(elem, c, value, 0); + return snd_mixer_selem_set_playback_dB(elem, c, value, dir); }

static int set_capture_dB(snd_mixer_elem_t *elem, - snd_mixer_selem_channel_id_t c, long value) + snd_mixer_selem_channel_id_t c, long value, int dir) +{ + return snd_mixer_selem_set_capture_dB(elem, c, value, dir); +} + +static int set_playback_raw_volume(snd_mixer_elem_t *elem, + snd_mixer_selem_channel_id_t c, + long value, int dir) +{ + return snd_mixer_selem_set_playback_volume(elem, c, value); +} + +static int set_capture_raw_volume(snd_mixer_elem_t *elem, + snd_mixer_selem_channel_id_t c, + long value, int dir) +{ + return snd_mixer_selem_set_capture_volume(elem, c, value); +} + +/* FIXME: normalize to int32 space to be compatible with other types */ +#define MAP_VOL_RES (INT32_MAX / 100) + +static int get_mapped_volume_range(snd_mixer_elem_t *elem, + long *pmin, long *pmax) +{ + *pmin = 0; + *pmax = MAP_VOL_RES; + return 0; +} + +static int get_playback_mapped_volume(snd_mixer_elem_t *elem, + snd_mixer_selem_channel_id_t c, + long *value) +{ + *value = (rint)(get_normalized_playback_volume(elem, c) * MAP_VOL_RES); + return 0; +} + +static int set_playback_mapped_volume(snd_mixer_elem_t *elem, + snd_mixer_selem_channel_id_t c, + long value, int dir) { - return snd_mixer_selem_set_capture_dB(elem, c, value, 0); + return set_normalized_playback_volume(elem, c, + (double)value / MAP_VOL_RES, dir); +} + +static int get_capture_mapped_volume(snd_mixer_elem_t *elem, + snd_mixer_selem_channel_id_t c, + long *value) +{ + *value = (rint)(get_normalized_capture_volume(elem, c) * MAP_VOL_RES); + return 0; +} + +static int set_capture_mapped_volume(snd_mixer_elem_t *elem, + snd_mixer_selem_channel_id_t c, + long value, int dir) +{ + return set_normalized_capture_volume(elem, c, + (double)value / MAP_VOL_RES, dir); }

static const struct volume_ops_set vol_ops[2] = { @@ -315,29 +353,42 @@ static const struct volume_ops_set vol_ops[2] = { .has_volume = snd_mixer_selem_has_playback_volume, .v = {{ snd_mixer_selem_get_playback_volume_range, snd_mixer_selem_get_playback_volume, - snd_mixer_selem_set_playback_volume }, + set_playback_raw_volume }, { snd_mixer_selem_get_playback_dB_range, snd_mixer_selem_get_playback_dB, - set_playback_dB }}, + set_playback_dB }, + { get_mapped_volume_range, + get_playback_mapped_volume, + set_playback_mapped_volume }, + }, }, { .has_volume = snd_mixer_selem_has_capture_volume, .v = {{ snd_mixer_selem_get_capture_volume_range, snd_mixer_selem_get_capture_volume, - snd_mixer_selem_set_capture_volume }, + set_capture_raw_volume }, { snd_mixer_selem_get_capture_dB_range, snd_mixer_selem_get_capture_dB, - set_capture_dB }}, + set_capture_dB }, + { get_mapped_volume_range, + get_capture_mapped_volume, + set_capture_mapped_volume }, + }, }, };

+static int std_vol_type = VOL_RAW; + static int set_volume_simple(snd_mixer_elem_t *elem, snd_mixer_selem_channel_id_t chn, char **ptr, int dir) { long val, orig, pmin, pmax; char *p = *ptr, *s; - int invalid = 0, err = 0, vol_type = VOL_RAW; + int invalid = 0, percent = 0, err = 0; + int vol_type = std_vol_type; + double scale = 1.0; + int correct = 0;

if (! vol_ops[dir].has_volume(elem)) invalid = 1; @@ -347,10 +398,6 @@ static int set_volume_simple(snd_mixer_elem_t *elem, if (*p == '\0' || (!isdigit(*p) && *p != '-')) goto skip;

- if (! invalid && - vol_ops[dir].v[VOL_RAW].get_range(elem, &pmin, &pmax) < 0) - invalid = 1; - s = p; val = strtol(s, &p, 10); if (*p == '.') { @@ -358,32 +405,37 @@ static int set_volume_simple(snd_mixer_elem_t *elem, strtol(p, &p, 10); } if (*p == '%') { - if (! invalid) - val = (long)convert_prange1(strtod(s, NULL), pmin, pmax); + percent = 1; p++; } else if (p[0] == 'd' && p[1] == 'B') { - if (! invalid) { - val = (long)(strtod(s, NULL) * 100.0); - vol_type = VOL_DB; - if (vol_ops[dir].v[vol_type].get_range(elem, &pmin, &pmax) < 0) - invalid = 1; - } + vol_type = VOL_DB; p += 2; - } + scale = 100; + } else + vol_type = VOL_RAW; + + val = (long)(strtod(s, NULL) * scale); + if (vol_ops[dir].v[vol_type].get_range(elem, &pmin, &pmax) < 0) + invalid = 1; + if (percent) + val = (long)convert_prange1(val, pmin, pmax); if (*p == '+' || *p == '-') { if (! invalid) { if (vol_ops[dir].v[vol_type].get(elem, chn, &orig) < 0) invalid = 1; - if (*p == '+') + if (*p == '+') { val = orig + val; - else + correct = -1; + } else { val = orig - val; + correct = 1; + } } p++; } if (! invalid) { val = check_range(val, pmin, pmax); - err = vol_ops[dir].v[vol_type].set(elem, chn, val); + err = vol_ops[dir].v[vol_type].set(elem, chn, val, correct); } skip: if (*p == ',') @@ -711,15 +763,33 @@ static int controls(int level) return 0; }

+static void show_selem_volume(snd_mixer_elem_t *elem, + snd_mixer_selem_channel_id_t chn, int dir, + long min, long max) +{ + long raw, val; + vol_ops[dir].v[VOL_RAW].get(elem, chn, &raw); + if (std_vol_type == VOL_RAW) + val = convert_prange(raw, min, max); + else { + vol_ops[dir].v[std_vol_type].get(elem, chn, &val); + val = convert_prange(val, 0, MAP_VOL_RES); + } + printf(" %li [%li%%]", raw, val); + if (!vol_ops[dir].v[VOL_DB].get(elem, chn, &val)) { + printf(" ["); + print_dB(val); + printf("]"); + } +} + static int show_selem(snd_mixer_t *handle, snd_mixer_selem_id_t *id, const char *space, int level) { snd_mixer_selem_channel_id_t chn; long pmin = 0, pmax = 0; long cmin = 0, cmax = 0; - long pvol, cvol; int psw, csw; int pmono, cmono, mono_ok = 0; - long db; snd_mixer_elem_t *elem; elem = snd_mixer_find_selem(handle, id); @@ -868,13 +938,7 @@ static int show_selem(snd_mixer_t *handle, snd_mixer_selem_id_t *id, const char mono_ok = 1; } if (snd_mixer_selem_has_common_volume(elem)) { - snd_mixer_selem_get_playback_volume(elem, SND_MIXER_SCHN_MONO, &pvol); - printf(" %s", get_percent(pvol, pmin, pmax)); - if (!snd_mixer_selem_get_playback_dB(elem, SND_MIXER_SCHN_MONO, &db)) { - printf(" ["); - print_dB(db); - printf("]"); - } + show_selem_volume(elem, SND_MIXER_SCHN_MONO, 0, pmin, pmax); } if (snd_mixer_selem_has_common_switch(elem)) { snd_mixer_selem_get_playback_switch(elem, SND_MIXER_SCHN_MONO, &psw); @@ -891,13 +955,7 @@ static int show_selem(snd_mixer_t *handle, snd_mixer_selem_id_t *id, const char if (snd_mixer_selem_has_playback_volume(elem)) { printf(" Playback"); title = 1; - snd_mixer_selem_get_playback_volume(elem, SND_MIXER_SCHN_MONO, &pvol); - printf(" %s", get_percent(pvol, pmin, pmax)); - if (!snd_mixer_selem_get_playback_dB(elem, SND_MIXER_SCHN_MONO, &db)) { - printf(" ["); - print_dB(db); - printf("]"); - } + show_selem_volume(elem, SND_MIXER_SCHN_MONO, 0, pmin, pmax); } } if (!snd_mixer_selem_has_common_switch(elem)) { @@ -919,13 +977,7 @@ static int show_selem(snd_mixer_t *handle, snd_mixer_selem_id_t *id, const char if (snd_mixer_selem_has_capture_volume(elem)) { printf(" Capture"); title = 1; - snd_mixer_selem_get_capture_volume(elem, SND_MIXER_SCHN_MONO, &cvol); - printf(" %s", get_percent(cvol, cmin, cmax)); - if (!snd_mixer_selem_get_capture_dB(elem, SND_MIXER_SCHN_MONO, &db)) { - printf(" ["); - print_dB(db); - printf("]"); - } + show_selem_volume(elem, SND_MIXER_SCHN_MONO, 1, cmin, cmax); } } if (!snd_mixer_selem_has_common_switch(elem)) { @@ -946,13 +998,7 @@ static int show_selem(snd_mixer_t *handle, snd_mixer_selem_id_t *id, const char continue; printf("%s%s:", space, snd_mixer_selem_channel_name(chn)); if (!pmono && !cmono && snd_mixer_selem_has_common_volume(elem)) { - snd_mixer_selem_get_playback_volume(elem, chn, &pvol); - printf(" %s", get_percent(pvol, pmin, pmax)); - if (!snd_mixer_selem_get_playback_dB(elem, chn, &db)) { - printf(" ["); - print_dB(db); - printf("]"); - } + show_selem_volume(elem, chn, 0, pmin, pmax); } if (!pmono && !cmono && snd_mixer_selem_has_common_switch(elem)) { snd_mixer_selem_get_playback_switch(elem, chn, &psw); @@ -964,13 +1010,7 @@ static int show_selem(snd_mixer_t *handle, snd_mixer_selem_id_t *id, const char if (snd_mixer_selem_has_playback_volume(elem)) { printf(" Playback"); title = 1; - snd_mixer_selem_get_playback_volume(elem, chn, &pvol); - printf(" %s", get_percent(pvol, pmin, pmax)); - if (!snd_mixer_selem_get_playback_dB(elem, chn, &db)) { - printf(" ["); - print_dB(db); - printf("]"); - } + show_selem_volume(elem, chn, 0, pmin, pmax); } } if (!snd_mixer_selem_has_common_switch(elem)) { @@ -988,13 +1028,7 @@ static int show_selem(snd_mixer_t *handle, snd_mixer_selem_id_t *id, const char if (snd_mixer_selem_has_capture_volume(elem)) { printf(" Capture"); title = 1; - snd_mixer_selem_get_capture_volume(elem, chn, &cvol); - printf(" %s", get_percent(cvol, cmin, cmax)); - if (!snd_mixer_selem_get_capture_dB(elem, chn, &db)) { - printf(" ["); - print_dB(db); - printf("]"); - } + show_selem_volume(elem, chn, 1, cmin, cmax); } } if (!snd_mixer_selem_has_common_switch(elem)) { @@ -1927,6 +1961,8 @@ int main(int argc, char *argv[]) {"version", 0, NULL, 'v'}, {"abstract", 1, NULL, 'a'}, {"stdin", 0, NULL, 's'}, + {"raw-volume", 0, NULL, 'R'}, + {"mapped-volume", 0, NULL, 'M'}, {NULL, 0, NULL, 0}, };

@@ -1934,7 +1970,7 @@ int main(int argc, char *argv[]) while (1) { int c;

- if ((c = getopt_long(argc, argv, "hc:D:qidnva:s", long_option, NULL)) < 0) + if ((c = getopt_long(argc, argv, "hc:D:qidnva:sRM", long_option, NULL)) < 0) break; switch (c) { case 'h': @@ -1987,6 +2023,12 @@ int main(int argc, char *argv[]) case 's': read_stdin = 1; break; + case 'R': + std_vol_type = VOL_RAW; + break; + case 'M': + std_vol_type = VOL_MAP; + break; default: fprintf(stderr, "Invalid switch or option needs an argument.\n"); morehelp++;