void audio_set_default_levels() {
int err;
snd_ctl_t *ctl;
snd_ctl_elem_value_t *val;
snd_ctl_elem_value_alloca(&val);
if (snd_ctl_open(&ctl, ALSA_DEVICE, 0)) {
fprintf(stderr, "can't open audio device");
return;
}
/* unmute microphone */
snd_ctl_elem_value_set_interface(val, SND_CTL_ELEM_IFACE_MIXER);
snd_ctl_elem_value_set_name(val, "Mic Capture Switch");
snd_ctl_elem_value_set_integer(val, 0, 1);
err = snd_ctl_elem_write(ctl, val);
if (err)
fprintf(stderr, "can't unmute microphone: %s\n", snd_strerror(err));
/* unmute speaker */
snd_ctl_elem_value_clear(val);
snd_ctl_elem_value_set_interface(val, SND_CTL_ELEM_IFACE_MIXER);
snd_ctl_elem_value_set_name(val, "Speaker Playback Switch");
snd_ctl_elem_value_set_integer(val, 0, 1);
err = snd_ctl_elem_write(ctl, val);
if (err)
fprintf(stderr, "can't unmute speaker: %s\n", snd_strerror(err));
/* set mic volume */
snd_ctl_elem_value_clear(val);
snd_ctl_elem_value_set_interface(val, SND_CTL_ELEM_IFACE_MIXER);
snd_ctl_elem_value_set_name(val, "Mic Capture Volume");
snd_ctl_elem_value_set_integer(val, 0, DEFAULT_MIC_VOL);
err = snd_ctl_elem_write(ctl, val);
if (err)
fprintf(stderr, "can't set microphone volume: %s\n", snd_strerror(err));
/* set speaker volume */
snd_ctl_elem_value_clear(val);
snd_ctl_elem_value_set_interface(val, SND_CTL_ELEM_IFACE_MIXER);
snd_ctl_elem_value_set_name(val, "Speaker Playback Volume");
snd_ctl_elem_value_set_integer(val, 0, DEFAULT_SPKR_VOL);
snd_ctl_elem_value_set_integer(val, 1, DEFAULT_SPKR_VOL);
err = snd_ctl_elem_write(ctl, val);
if (err)
fprintf(stderr, "can't set speaker volume: %s\n", snd_strerror(err));
/* set capture source */
snd_ctl_elem_value_clear(val);
snd_ctl_elem_value_set_interface(val, SND_CTL_ELEM_IFACE_MIXER);
snd_ctl_elem_value_set_name(val, "PCM Capture Source");
snd_ctl_elem_value_set_integer(val, 0, 0);
err = snd_ctl_elem_write(ctl, val);
if (err)
fprintf(stderr, "can't set capture source: %s\n", snd_strerror(err));
snd_ctl_close(ctl);
}
/**************************************************************************
* ALSA_CheckSetVolume [internal]
*
* Helper function for Alsa volume queries. This tries to simplify
* the process of managing the volume. All parameters are optional
* (pass NULL to ignore or not use).
* Return values are MMSYSERR_NOERROR on success, or !0 on failure;
* error codes are normalized into the possible documented return
* values from waveOutGetVolume.
*/
int ALSA_CheckSetVolume(snd_hctl_t *hctl, int *out_left, int *out_right,
int *out_min, int *out_max, int *out_step,
int *new_left, int *new_right)
{
int rc = MMSYSERR_NOERROR;
int value_count = 0;
snd_hctl_elem_t * elem = NULL;
snd_ctl_elem_info_t * eleminfop = NULL;
snd_ctl_elem_value_t * elemvaluep = NULL;
snd_ctl_elem_id_t * elemidp = NULL;
const char *names[] = {"PCM Playback Volume", "Line Playback Volume", NULL};
const char **name;
#define EXIT_ON_ERROR(f,txt,exitcode) do \
{ \
int err; \
if ( (err = (f) ) < 0) \
{ \
ERR(txt " failed: %s\n", snd_strerror(err)); \
rc = exitcode; \
goto out; \
} \
} while(0)
if (! hctl)
return MMSYSERR_NOTSUPPORTED;
/* Allocate areas to return information about the volume */
EXIT_ON_ERROR(snd_ctl_elem_id_malloc(&elemidp), "snd_ctl_elem_id_malloc", MMSYSERR_NOMEM);
EXIT_ON_ERROR(snd_ctl_elem_value_malloc (&elemvaluep), "snd_ctl_elem_value_malloc", MMSYSERR_NOMEM);
EXIT_ON_ERROR(snd_ctl_elem_info_malloc (&eleminfop), "snd_ctl_elem_info_malloc", MMSYSERR_NOMEM);
snd_ctl_elem_id_clear(elemidp);
snd_ctl_elem_value_clear(elemvaluep);
snd_ctl_elem_info_clear(eleminfop);
/* Setup and find an element id that exactly matches the characteristic we want
** FIXME: It is probably short sighted to hard code and fixate on PCM Playback Volume */
for( name = names; *name; name++ )
{
snd_ctl_elem_id_set_name(elemidp, *name);
snd_ctl_elem_id_set_interface(elemidp, SND_CTL_ELEM_IFACE_MIXER);
elem = snd_hctl_find_elem(hctl, elemidp);
if (elem)
{
/* Read and return volume information */
EXIT_ON_ERROR(snd_hctl_elem_info(elem, eleminfop), "snd_hctl_elem_info", MMSYSERR_NOTSUPPORTED);
value_count = snd_ctl_elem_info_get_count(eleminfop);
if (out_min || out_max || out_step)
{
if (!snd_ctl_elem_info_is_readable(eleminfop))
{
ERR("snd_ctl_elem_info_is_readable returned false; cannot return info\n");
rc = MMSYSERR_NOTSUPPORTED;
goto out;
}
if (out_min)
*out_min = snd_ctl_elem_info_get_min(eleminfop);
if (out_max)
*out_max = snd_ctl_elem_info_get_max(eleminfop);
if (out_step)
*out_step = snd_ctl_elem_info_get_step(eleminfop);
}
if (out_left || out_right)
{
EXIT_ON_ERROR(snd_hctl_elem_read(elem, elemvaluep), "snd_hctl_elem_read", MMSYSERR_NOTSUPPORTED);
if (out_left)
*out_left = snd_ctl_elem_value_get_integer(elemvaluep, 0);
if (out_right)
{
if (value_count == 1)
*out_right = snd_ctl_elem_value_get_integer(elemvaluep, 0);
else if (value_count == 2)
*out_right = snd_ctl_elem_value_get_integer(elemvaluep, 1);
else
{
ERR("Unexpected value count %d from snd_ctl_elem_info_get_count while getting volume info\n", value_count);
rc = -1;
goto out;
}
}
}
/* Set the volume */
if (new_left || new_right)
{
EXIT_ON_ERROR(snd_hctl_elem_read(elem, elemvaluep), "snd_hctl_elem_read", MMSYSERR_NOTSUPPORTED);
if (new_left)
snd_ctl_elem_value_set_integer(elemvaluep, 0, *new_left);
if (new_right)
{
if (value_count == 1)
snd_ctl_elem_value_set_integer(elemvaluep, 0, *new_right);
else if (value_count == 2)
snd_ctl_elem_value_set_integer(elemvaluep, 1, *new_right);
else
{
ERR("Unexpected value count %d from snd_ctl_elem_info_get_count while setting volume info\n", value_count);
rc = -1;
goto out;
}
}
EXIT_ON_ERROR(snd_hctl_elem_write(elem, elemvaluep), "snd_hctl_elem_write", MMSYSERR_NOTSUPPORTED);
}
break;
}
}
if( !*name )
{
ERR("Could not find '{PCM,Line} Playback Volume' element\n");
rc = MMSYSERR_NOTSUPPORTED;
}
#undef EXIT_ON_ERROR
out:
if (elemvaluep)
snd_ctl_elem_value_free(elemvaluep);
if (eleminfop)
snd_ctl_elem_info_free(eleminfop);
if (elemidp)
snd_ctl_elem_id_free(elemidp);
return rc;
}
