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add flush and delay functions, modify volume curve, add some diagnostics

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This commit is contained in:
Mike Brady
2014-04-30 20:31:19 +01:00
parent 459cdd94ce
commit 2c40f23f43
1 changed files with 100 additions and 28 deletions
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audio_alsa.c
+100 -28
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@@ -39,7 +39,11 @@ static void deinit(void);
static void start(int sample_rate);
static void play(short buf[], int samples);
static void stop(void);
static void flush(void);
static uint32_t delay(void);
static void volume(double vol);
static int has_mute=0;
static int has_db_vol=0;
audio_output audio_alsa = {
.name = "alsa",
@@ -48,6 +52,8 @@ audio_output audio_alsa = {
.deinit = &deinit,
.start = &start,
.stop = &stop,
.flush = &flush,
.delay = &delay,
.play = &play,
.volume = NULL
};
@@ -65,6 +71,9 @@ static char *alsa_mix_dev = NULL;
static char *alsa_mix_ctrl = "Master";
static int alsa_mix_index = 0;
static int play_number;
static int64_t accumulated_delay,accumulated_da_delay;
static void help(void) {
printf(" -d output-device set the output device [default*|...]\n"
" -t mixer-type set the mixer type [software*|hardware]\n"
@@ -115,7 +124,7 @@ static int init(int argc, char **argv) {
if (alsa_mix_dev == NULL)
alsa_mix_dev = alsa_out_dev;
audio_alsa.volume = &volume;
int ret = 0;
long alsa_mix_maxv;
@@ -137,8 +146,20 @@ static int init(int argc, char **argv) {
alsa_mix_elem = snd_mixer_find_selem(alsa_mix_handle, alsa_mix_sid);
if (!alsa_mix_elem)
die ("Failed to find mixer element");
snd_mixer_selem_get_playback_volume_range (alsa_mix_elem, &alsa_mix_minv, &alsa_mix_maxv);
alsa_mix_range = alsa_mix_maxv - alsa_mix_minv;
if (snd_mixer_selem_get_playback_dB_range (alsa_mix_elem, &alsa_mix_minv, &alsa_mix_maxv)==0) {
has_db_vol=1;
debug(1,"Hardware mixer has dB volume from %ld to %ld.\n",alsa_mix_minv,alsa_mix_maxv);
audio_alsa.volume = &volume;
alsa_mix_range = alsa_mix_maxv - alsa_mix_minv;
} else {
debug(1,"Hardware mixer does not have dB volume -- linear only??\n");
}
if (snd_mixer_selem_has_playback_switch(alsa_mix_elem)) {
has_mute=1;
debug(1,"Has mute ability.\n");
}
return 0;
}
@@ -151,33 +172,76 @@ static void deinit(void) {
}
static void start(int sample_rate) {
if (sample_rate != 44100)
die("Unexpected sample rate!");
if (sample_rate != 44100)
die("Unexpected sample rate!");
unsigned int mysamplerate=sample_rate;
int ret, dir = 0;
snd_pcm_uframes_t frames = 64;
ret = snd_pcm_open(&alsa_handle, alsa_out_dev, SND_PCM_STREAM_PLAYBACK, 0);
if (ret < 0)
die("Alsa initialization failed: unable to open pcm device: %s\n", snd_strerror(ret));
int ret, dir = 0;
snd_pcm_uframes_t frames = 441*10;
snd_pcm_uframes_t buffer_size = frames*4;
ret = snd_pcm_open(&alsa_handle, alsa_out_dev, SND_PCM_STREAM_PLAYBACK, 0);
if (ret < 0)
die("Alsa initialization failed: unable to open pcm device: %s\n", snd_strerror(ret));
snd_pcm_hw_params_alloca(&alsa_params);
snd_pcm_hw_params_any(alsa_handle, alsa_params);
snd_pcm_hw_params_set_access(alsa_handle, alsa_params, SND_PCM_ACCESS_RW_INTERLEAVED);
snd_pcm_hw_params_set_format(alsa_handle, alsa_params, SND_PCM_FORMAT_S16);
snd_pcm_hw_params_set_channels(alsa_handle, alsa_params, 2);
snd_pcm_hw_params_set_rate_near(alsa_handle, alsa_params, (unsigned int *)&sample_rate, &dir);
snd_pcm_hw_params_set_period_size_near(alsa_handle, alsa_params, &frames, &dir);
ret = snd_pcm_hw_params(alsa_handle, alsa_params);
if (ret < 0)
die("unable to set hw parameters: %s\n", snd_strerror(ret));
snd_pcm_hw_params_alloca(&alsa_params);
snd_pcm_hw_params_any(alsa_handle, alsa_params);
snd_pcm_hw_params_set_access(alsa_handle, alsa_params, SND_PCM_ACCESS_RW_INTERLEAVED);
snd_pcm_hw_params_set_format(alsa_handle, alsa_params, SND_PCM_FORMAT_S16);
snd_pcm_hw_params_set_channels(alsa_handle, alsa_params, 2);
snd_pcm_hw_params_set_rate_near(alsa_handle, alsa_params, (unsigned int *)&mysamplerate, &dir);
// snd_pcm_hw_params_set_period_size_near(alsa_handle, alsa_params, &frames, &dir);
// snd_pcm_hw_params_set_buffer_size_near(alsa_handle, alsa_params, &buffer_size);
ret = snd_pcm_hw_params(alsa_handle, alsa_params);
if (ret < 0)
die("unable to set hw parameters: %s\n", snd_strerror(ret));
if (mysamplerate!=sample_rate) {
die("Can't set the D/A converter to %d -- set to %d instead./n",sample_rate,mysamplerate);
}
}
static uint32_t delay() {
snd_pcm_sframes_t current_delay = 0;
int derr;
if ((snd_pcm_state(alsa_handle)==SND_PCM_STATE_PREPARED) || (snd_pcm_state(alsa_handle)==SND_PCM_STATE_RUNNING))
if (derr = snd_pcm_delay(alsa_handle,&current_delay)) {
// debug(1,"Error getting delay in delay(): %s\n", snd_strerror(derr));
current_delay=0;
}
return current_delay;
}
static void play(short buf[], int samples) {
int err = snd_pcm_writei(alsa_handle, (char*)buf, samples);
if (err < 0)
err = snd_pcm_recover(alsa_handle, err, 0);
if (err < 0)
die("Failed to write to PCM device: %s\n", snd_strerror(err));
snd_pcm_sframes_t current_delay = 0;
int err;
if ((snd_pcm_state(alsa_handle)==SND_PCM_STATE_PREPARED) || (snd_pcm_state(alsa_handle)==SND_PCM_STATE_RUNNING)) {
if (err = snd_pcm_delay(alsa_handle,&current_delay)) {
debug(1,"Error getting delay in play(): %s\n", snd_strerror(err));
current_delay=0;
}
err = snd_pcm_writei(alsa_handle, (char*)buf, samples);
if (err < 0) {
err = snd_pcm_recover(alsa_handle, err, 0);
debug(1,"Error writing in play(): %s\n", snd_strerror(err));
}
//if (err < 0)
// die("Failed to write to PCM device: %s.\n", snd_strerror(err));
} //else {
//debug(1,"Playing blocked -- state is %d.\n",snd_pcm_state(alsa_handle));
//}
// return current_delay;
}
static void flush(void) {
int derr;
if (alsa_handle) {
// debug(1,"Dropping frames for flush...\n");
if (derr = snd_pcm_drop(alsa_handle))
debug(1,"Error dropping frames: %s\n", snd_strerror(derr));
// debug(1,"Dropped frames ok. State is %d.\n",snd_pcm_state(alsa_handle));
if (derr = snd_pcm_prepare(alsa_handle))
debug(1,"Error preparing after flush: %s\n", snd_strerror(derr));
// debug(1,"Frames successfully dropped.\n");
}
}
static void stop(void) {
@@ -189,7 +253,15 @@ static void stop(void) {
}
static void volume(double vol) {
long alsa_volume = (vol*alsa_mix_range)+alsa_mix_minv;
if(snd_mixer_selem_set_playback_volume_all(alsa_mix_elem, alsa_volume) != 0)
die ("Failed to set playback volume");
if (has_db_vol) {
// guess that if the range is 60db or greater, that it's amplitude rather than power, do multiply by 2, i.e. 200
uint32_t multiplier = 200;
if (alsa_mix_range<6000)
multiplier=alsa_mix_range/30;
// otherwise multiply by <range in db>/30
if(snd_mixer_selem_set_playback_dB_all(alsa_mix_elem, vol*multiplier+alsa_mix_range+alsa_mix_minv, -1) != 0)
die ("Failed to set playback dB volume");
}
if (has_mute)
snd_mixer_selem_set_playback_switch_all(alsa_mix_elem, (vol!=-144.0));
}