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Improve ALSA device initialization
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@RoEdAl
RoEdAl committed Jun 20, 2024
1 parent cd7af47 commit e334a90
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Showing 2 changed files with 18 additions and 16 deletions.
33 changes: 17 additions & 16 deletions src/pcm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,7 @@ static snd_pcm_uframes_t adjust_uframes(snd_pcm_uframes_t ptime, unsigned int ra

static snd_pcm_uframes_t adjust_start_threshold(snd_pcm_uframes_t ptime)
{
static const size_t PTIME_MIN_START_THRESHOLD = 100u;
static const size_t PTIME_MIN_START_THRESHOLD = 80u;
static const size_t PTIME_MAX_START_THRESHOLD = 250u;

if (ptime < PTIME_MIN_START_THRESHOLD) {
Expand Down Expand Up @@ -99,10 +99,13 @@ int pcm_init(const char* dev, snd_pcm_stream_t stream, const struct ast_format*
#else
const size_t ptime = (stream == SND_PCM_STREAM_CAPTURE) ? PTIME_CAPTURE : PTIME_PLAYBACK;
#endif
snd_pcm_uframes_t period_size = adjust_uframes(ptime + 10, rate);
snd_pcm_uframes_t buffer_size = adjust_uframes(PTIME_BUFFER, rate);
snd_pcm_uframes_t start_threshold = adjust_uframes(adjust_start_threshold(ptime * 2), rate);
snd_pcm_uframes_t stop_threshold = buffer_size - period_size;
const size_t ptime_ex = ptime + PTIME_EXTRA;
unsigned int period_time = ptime_ex * 1000; // us
int period_dir = 0;
unsigned int buffer_time = PTIME_BUFFER * 1000; // us
int buffer_dir = 0;
snd_pcm_uframes_t start_threshold = adjust_uframes(adjust_start_threshold(ptime_ex * 2), rate);
snd_pcm_uframes_t stop_threshold = adjust_uframes(PTIME_BUFFER - (2 * ptime_ex), rate);
snd_pcm_uframes_t boundary = 0u;
unsigned int hwrate = rate;
unsigned int channels = 1;
Expand Down Expand Up @@ -145,15 +148,15 @@ int pcm_init(const char* dev, snd_pcm_stream_t stream, const struct ast_format*
goto alsa_fail;
}

res = snd_pcm_hw_params_set_period_size_near(handle, hwparams, &period_size, NULL);
res = snd_pcm_hw_params_set_period_time_near(handle, hwparams, &period_time, &period_dir);
if (res < 0) {
ast_log(LOG_ERROR, "[ALSA][%s] HW Period size (%lu frames) is bad: %s\n", stream_str, period_size, snd_strerror(res));
ast_log(LOG_ERROR, "[ALSA][%s] HW Period time (%u us) is bad: %s\n", stream_str, period_time, snd_strerror(res));
goto alsa_fail;
}

res = snd_pcm_hw_params_set_buffer_size_near(handle, hwparams, &buffer_size);
res = snd_pcm_hw_params_set_buffer_time_near(handle, hwparams, &buffer_time, &buffer_dir);
if (res < 0) {
ast_log(LOG_ERROR, "[ALSA][%s] HW Problem setting buffer size of %lu: %s\n", stream_str, buffer_size, snd_strerror(res));
ast_log(LOG_ERROR, "[ALSA][%s] HW Problem setting buffer time of %u: %s\n", stream_str, buffer_time, snd_strerror(res));
goto alsa_fail;
}

Expand Down Expand Up @@ -185,14 +188,14 @@ int pcm_init(const char* dev, snd_pcm_stream_t stream, const struct ast_format*

ast_debug(1, "[ALSA][%s] Rate: %u\n", stream_str, hw_params_get_rate(hwparams));

res = snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
res = snd_pcm_hw_params_get_period_time(hwparams, &period_time, &period_dir);
if (res >= 0) {
ast_debug(1, "[ALSA][%s] Period size: %lu\n", stream_str, period_size);
ast_debug(1, "[ALSA][%s] Period time: %u, dir:%d\n", stream_str, period_time / 1000, period_dir);
}

res = snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
res = snd_pcm_hw_params_get_buffer_time(hwparams, &buffer_time, &buffer_dir);
if (res >= 0) {
ast_debug(1, "[ALSA][%s] Buffer size: %lu\n", stream_str, buffer_size);
ast_debug(1, "[ALSA][%s] Buffer time: %u, dir:%d\n", stream_str, buffer_time / 1000, buffer_dir);
}

swparams = ast_alloca(snd_pcm_sw_params_sizeof());
Expand All @@ -211,15 +214,13 @@ int pcm_init(const char* dev, snd_pcm_stream_t stream, const struct ast_format*
ast_debug(3, "[ALSA][%s] Boundary: %lu\n", stream_str, boundary);

if (stream == SND_PCM_STREAM_PLAYBACK) {
ast_debug(2, "[ALSA][%s] Start threshold: %lu\n", stream_str, start_threshold);
ast_debug(3, "[ALSA][%s] Thresholds: %lu %lu\n", stream_str, start_threshold, stop_threshold);
res = snd_pcm_sw_params_set_start_threshold(handle, swparams, start_threshold);

if (res < 0) {
ast_log(LOG_ERROR, "[ALSA][%s] SW Couldn't set start threshold: %s\n", stream_str, snd_strerror(res));
goto alsa_fail;
}

ast_debug(2, "[ALSA][%s] Stop threshold: %lu, free: %lu\n", stream_str, stop_threshold, buffer_size - stop_threshold);
res = snd_pcm_sw_params_set_stop_threshold(handle, swparams, stop_threshold);
if (res < 0) {
ast_log(LOG_ERROR, "[ALSA][%s] SW Couldn't set stop threshold: %s\n", stream_str, snd_strerror(res));
Expand Down
1 change: 1 addition & 0 deletions src/ptime-config.h.in
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
#define PTIME_CAPTURE 20
#define PTIME_PLAYBACK 20
#define PTIME_BUFFER 1000
#define PTIME_EXTRA 10

#cmakedefine01 PTIME_USE_DEFAULT

Expand Down

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