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alsa: refactor dll code

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This commit is contained in:
Wim Taymans 2020-12-09 12:09:40 +01:00
parent 5469ac19ab
commit d776a0917d
6 changed files with 114 additions and 108 deletions
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46
spa/plugins/alsa/test-timer.c
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@ -30,6 +30,8 @@
#include <alsa/asoundlib.h>
#include <dll.h>
#define DEFAULT_DEVICE "hw:0"
#define M_PI_M2 (M_PI + M_PI)
@ -37,8 +39,6 @@
#define NSEC_PER_SEC 1000000000ll
#define TIMESPEC_TO_NSEC(ts) ((ts)->tv_sec * NSEC_PER_SEC + (ts)->tv_nsec)
#define BW_MAX 0.128
#define BW_MIN 0.016
#define BW_PERIOD (NSEC_PER_SEC * 3)
struct state {
@ -54,34 +54,9 @@ struct state {
uint64_t next_time;
uint64_t prev_time;
double bw;
double z1, z2, z3;
double w0, w1, w2;
struct spa_dll dll;
};
static void dll_init(struct state *state)
{
state->bw = 0.0;
state->z1 = state->z2 = state->z3 = 0.0;
}
static void dll_set_bw(struct state *state, double bw)
{
double w = M_PI_M2 * bw * state->period / state->rate;
state->w0 = 1.0 - exp (-20.0 * w);
state->w1 = w * 1.5 / state->period;
state->w2 = w / 1.5;
state->bw = bw;
}
static double dll_update(struct state *state, double err)
{
state->z1 += state->w0 * (state->w1 * err - state->z1);
state->z2 += state->w0 * (state->z1 - state->z2);
state->z3 += state->w2 * state->z2;
return 1.0 - (state->z2 + state->z3);
}
static int set_timeout(struct state *state, uint64_t time)
{
struct itimerspec ts;
@ -138,8 +113,8 @@ static int on_timer_wakeup(struct state *state)
* samples remaining in the device when we wakeup. */
error = (double)delay - (double)state->period;
/* update the dll with the error, this gives a rate corection */
corr = dll_update(state, error);
/* update the dll with the error, this gives a rate correction */
corr = spa_dll_update(&state->dll, error);
/* set our new adjusted timeout. alternatively, this value can
* instead be used to drive a resampler if this device is
@ -151,11 +126,12 @@ static int on_timer_wakeup(struct state *state)
state->prev_time = state->next_time;
/* reduce bandwidth and show some stats */
if (state->bw > BW_MIN)
dll_set_bw(state, state->bw / 2.0);
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->bw);
corr, error, state->dll.bw);
}
/* pull in new samples write a new period */
write_period(state);
@ -193,8 +169,8 @@ int main(int argc, char *argv[])
snd_pcm_format_name(SND_PCM_FORMAT_S32_LE),
state.rate, state.channels);
dll_init(&state);
dll_set_bw(&state, BW_MAX);
spa_dll_init(&state.dll);
spa_dll_set_bw(&state.dll, SPA_DLL_BW_MAX, state.period, state.rate);
if ((state.timerfd = timerfd_create(CLOCK_MONOTONIC, 0)) < 0)
perror("timerfd");