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alsa: update test-timer

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Remove the bandwidth reduce, we don't do that.
Clamp large errors.
Add htimestamp mode, which seems more stable.
This commit is contained in:
Wim Taymans 2022-02-03 16:17:38 +01:00
parent ee2e6412d3
commit 7480d09589
1 changed files with 40 additions and 9 deletions
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49
spa/plugins/alsa/test-timer.c
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@ -45,10 +45,12 @@ struct state {
unsigned int rate;
unsigned int channels;
snd_pcm_uframes_t period;
snd_pcm_uframes_t buffer_frames;
snd_pcm_t *hndl;
int timerfd;
double max_error;
float accumulator;
uint64_t next_time;
@ -103,15 +105,36 @@ static int write_period(struct state *state)
static int on_timer_wakeup(struct state *state)
{
snd_pcm_sframes_t avail, delay;
snd_pcm_sframes_t delay;
double error, corr;
#if 1
snd_pcm_sframes_t avail;
CHECK(snd_pcm_avail_delay(state->hndl, &avail, &delay), "delay");
#else
snd_pcm_uframes_t avail;
snd_htimestamp_t tstamp;
uint64_t then;
/* check the delay in the device */
CHECK(snd_pcm_avail_delay(state->hndl, &avail, &delay), "delay");
CHECK(snd_pcm_htimestamp(state->hndl, &avail, &tstamp), "htimestamp");
delay = state->buffer_frames - avail;
then = TIMESPEC_TO_NSEC(&tstamp);
if (then != 0) {
if (then < state->next_time) {
delay -= (state->next_time - then) * state->rate / NSEC_PER_SEC;
} else {
delay += (then - state->next_time) * state->rate / NSEC_PER_SEC;
}
}
#endif
/* calculate the error, we want to have exactly 1 period of
* samples remaining in the device when we wakeup. */
error = (double)delay - (double)state->period;
if (error > state->max_error)
error = state->max_error;
else if (error < -state->max_error)
error = -state->max_error;
/* update the dll with the error, this gives a rate correction */
corr = spa_dll_update(&state->dll, error);
@ -124,12 +147,6 @@ static int on_timer_wakeup(struct state *state)
if (state->next_time - state->prev_time > BW_PERIOD) {
state->prev_time = state->next_time;
/* reduce bandwidth and show some stats */
if (state->dll.bw > SPA_DLL_BW_MIN)
spa_dll_set_bw(&state->dll, state->dll.bw / 2.0,
state->period, state->rate);
fprintf(stdout, "corr:%f error:%f bw:%f\n",
corr, error, state->dll.bw);
}
@ -144,6 +161,7 @@ int main(int argc, char *argv[])
struct state state = { 0, };
const char *device = DEFAULT_DEVICE;
snd_pcm_hw_params_t *hparams;
snd_pcm_sw_params_t *sparams;
struct timespec now;
CHECK(snd_pcm_open(&state.hndl, device, SND_PCM_STREAM_PLAYBACK, 0), "open %s failed", device);
@ -165,12 +183,25 @@ int main(int argc, char *argv[])
&state.rate, 0), "set rate");
CHECK(snd_pcm_hw_params(state.hndl, hparams), "hw_params");
CHECK(snd_pcm_hw_params_get_buffer_size(hparams, &state.buffer_frames), "get_buffer_size_max");
fprintf(stdout, "opened format:%s rate:%u channels:%u\n",
snd_pcm_format_name(SND_PCM_FORMAT_S32_LE),
state.rate, state.channels);
snd_pcm_sw_params_alloca(&sparams);
#if 0
CHECK(snd_pcm_sw_params_current(state.hndl, sparams), "sw_params_current");
CHECK(snd_pcm_sw_params_set_tstamp_mode(state.hndl, sparams, SND_PCM_TSTAMP_ENABLE),
"sw_params_set_tstamp_type");
CHECK(snd_pcm_sw_params_set_tstamp_type(state.hndl, sparams, SND_PCM_TSTAMP_TYPE_MONOTONIC),
"sw_params_set_tstamp_type");
CHECK(snd_pcm_sw_params(state.hndl, sparams), "sw_params");
#endif
spa_dll_init(&state.dll);
spa_dll_set_bw(&state.dll, SPA_DLL_BW_MAX, state.period, state.rate);
state.max_error = 256.0;
if ((state.timerfd = timerfd_create(CLOCK_MONOTONIC, 0)) < 0)
perror("timerfd");