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synced 2025-12-16 08:56:45 -05:00
alsa: improve rate control
Try to match the delay with the target delay. Use the rate to adjust the timeout period for master or the resampler rate for slaves.
This commit is contained in:
Wim Taymans
parent
df4cb30c7a
commit
b7cc9ea102
2 changed files with 88 additions and 114 deletions
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@ -501,6 +501,21 @@ static int set_timeout(struct state *state, uint64_t time)
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return 0;
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}
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static void init_loop(struct state *state)
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{
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state->bw = 0.0;
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state->z1 = state->z2 = state->z3 = 0.0;
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}
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static void set_loop(struct state *state, double bw)
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{
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double w = 2 * M_PI * bw * state->threshold / state->rate;
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state->w0 = 1.0 - exp (-20.0 * w);
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state->w1 = w * 1.5 / state->threshold;
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state->w2 = w / 1.5;
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state->bw = bw;
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}
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static int alsa_recover(struct state *state, int err)
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{
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int res, st;
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@ -539,7 +554,7 @@ static int alsa_recover(struct state *state, int err)
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spa_log_error(state->log, "snd_pcm_recover error: %s", snd_strerror(res));
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return res;
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}
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dll_init(&state->dll, DLL_BW_MAX);
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init_loop(state);
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if (state->stream == SND_PCM_STREAM_CAPTURE) {
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if ((res = snd_pcm_start(state->hndl)) < 0) {
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@ -575,70 +590,60 @@ static int get_status(struct state *state, snd_pcm_sframes_t *delay)
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return 0;
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}
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static int update_time(struct state *state, uint64_t nsec, snd_pcm_sframes_t delay, bool slaved)
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static int update_time(struct state *state, uint64_t nsec, snd_pcm_sframes_t delay, bool slave)
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{
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uint64_t sample_time, elapsed;
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double tw = 0.0, extra = 0.0;
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int64_t sdelay;
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double err, corr, elapsed;
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sample_time = state->sample_count;
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if (!slaved) {
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elapsed = sample_time - state->sample_time;
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} else {
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elapsed = state->threshold;
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if (state->bw == 0.0) {
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set_loop(state, BW_MAX);
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state->next_time = nsec;
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state->base_time = nsec;
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}
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if (state->stream == SND_PCM_STREAM_CAPTURE) {
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elapsed = state->threshold;
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extra = (double) elapsed / state->rate;
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sdelay = (int64_t)(delay - elapsed);
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} else {
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if (elapsed == 0) {
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elapsed = state->threshold / 2;
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delay = state->threshold / 2;
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}
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state->sample_time = sample_time;
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sdelay = -delay;
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err = delay - state->threshold;
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state->z1 += state->w0 * (state->w1 * err - state->z1);
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state->z2 += state->w0 * (state->z1 - state->z2);
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state->z3 += state->w2 * state->z2;
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corr = 1.0 - (state->z2 + state->z3);
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elapsed = (state->next_time - state->base_time) * 1e-9;
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if (elapsed > BW_PERIOD) {
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state->base_time = state->next_time;
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if (state->bw == BW_MAX)
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set_loop(state, BW_MED);
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else if (state->bw == BW_MED)
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set_loop(state, BW_MIN);
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spa_log_debug(state->log, "slave:%d rate:%f bw:%f", slave, corr, state->bw);
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}
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/* we try to match the delay with the number of delayed samples */
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tw = nsec * 1e-9 - (double)sdelay / state->rate - state->safety;
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tw = dll_update(&state->dll, tw, (double)elapsed / state->rate);
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state->next_time = (tw + extra - state->safety) * 1e9;
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if (state->dll.bw > DLL_BW_MIN && tw > state->dll.base + DLL_BW_PERIOD)
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dll_bandwidth(&state->dll, DLL_BW_MIN);
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if (state->clock) {
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state->clock->nsec = state->last_time;
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if (slave && state->notify) {
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struct spa_pod_builder b = { 0 };
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struct spa_pod_frame f[2];
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spa_pod_builder_init(&b, state->notify, 1024);
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spa_pod_builder_push_sequence(&b, &f[0], 0);
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spa_pod_builder_control(&b, 0, SPA_CONTROL_Properties);
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spa_pod_builder_push_object(&b, &f[1], SPA_TYPE_OBJECT_Props, SPA_PARAM_Props);
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spa_pod_builder_prop(&b, SPA_PROP_rate, 0);
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spa_pod_builder_double(&b, SPA_CLAMP(corr, 0.95, 1.05));
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spa_pod_builder_pop(&b, &f[1]);
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spa_pod_builder_pop(&b, &f[0]);
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}
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if (!slave && state->clock) {
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state->clock->nsec = state->next_time;
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state->clock->rate = SPA_FRACTION(1, state->rate);
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state->clock->position = state->sample_count;
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state->clock->delay = sdelay;
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state->clock->rate_diff = state->dll.dt;
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state->clock->delay = state->threshold * corr;
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state->clock->rate_diff = corr;
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}
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state->old_dt = SPA_CLAMP(state->dll.dt, 0.95, 1.05);
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spa_log_trace_fp(state->log, "%"PRIu64" %f %ld %f %f %d", nsec,
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corr, delay, err, state->threshold * corr,
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state->threshold);
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#if 0
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if (slaved && state->notify) {
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struct spa_pod_builder b = { 0 };
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spa_pod_builder_init(&b, state->notify, 1024);
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spa_pod_builder_push_sequence(&b, 0);
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spa_pod_builder_control(&b, 0, SPA_CONTROL_Properties);
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spa_pod_builder_push_object(&b, SPA_TYPE_OBJECT_Props, SPA_PARAM_Props);
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spa_pod_builder_prop(&b, SPA_PROP_rate, 0);
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spa_pod_builder_double(&b, state->old_dt);
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spa_pod_builder_pop(&b);
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spa_pod_builder_pop(&b);
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}
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#endif
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spa_log_trace_fp(state->log, "%"PRIu64" %f %"PRIi64" %"PRIi64" %"PRIi64" %d %"PRIu64" %f %f", nsec,
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state->old_dt, delay, elapsed, (int64_t)(nsec - state->last_time),
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state->threshold, state->next_time, tw, extra);
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state->last_time = nsec;
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state->next_time += state->threshold / corr * 1e9 / state->rate;
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return 0;
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}
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@ -653,22 +658,28 @@ int spa_alsa_write(struct state *state, snd_pcm_uframes_t silence)
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if (state->position && state->threshold != state->position->size)
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state->threshold = state->position->size;
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if (state->slaved) {
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uint64_t nsec, master;
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if (state->slaved && state->alsa_started) {
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uint64_t nsec;
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snd_pcm_sframes_t delay;
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master = state->position->clock.position + state->position->clock.delay;
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nsec = master * SPA_NSEC_PER_SEC / state->rate;
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clock_gettime(CLOCK_MONOTONIC, &state->now);
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if ((res = get_status(state, &delay)) < 0)
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return res;
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if (state->alsa_sync) {
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if (delay > state->threshold)
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snd_pcm_rewind(state->hndl, delay - state->threshold);
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else
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snd_pcm_forward(state->hndl, state->threshold - delay);
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delay = state->threshold;
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state->alsa_sync = false;
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}
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nsec = SPA_TIMESPEC_TO_NSEC(&state->now);
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if ((res = update_time(state, nsec, delay, true)) < 0)
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return res;
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spa_log_trace_fp(state->log, "slave %f %"PRIi64" %"PRIu64" %d",
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state->dll.dt, nsec, delay, state->rate);
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if (delay > state->threshold * 2) {
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spa_log_warn(state->log, "slave: skip period");
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snd_pcm_rewind(state->hndl, state->threshold);
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@ -850,9 +861,6 @@ int spa_alsa_read(struct state *state, snd_pcm_uframes_t silence)
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if ((res = update_time(state, nsec, delay, true)) < 0)
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return res;
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spa_log_trace_fp(state->log, "slave %f %"PRIi64" %"PRIu64" %d",
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state->dll.dt, nsec, delay, state->rate);
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if (delay > state->threshold * 2) {
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spa_log_trace_fp(state->log, "slave: skip period");
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snd_pcm_forward(state->hndl, state->threshold);
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@ -895,7 +903,7 @@ static int handle_play(struct state *state, uint64_t nsec, snd_pcm_sframes_t del
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if (delay >= state->threshold * 2) {
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spa_log_trace(state->log, "early wakeup %ld %d", delay, state->threshold);
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state->next_time = nsec + (state->threshold / 2) * SPA_NSEC_PER_SEC / state->rate;
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state->next_time = nsec + state->threshold * SPA_NSEC_PER_SEC / state->rate;
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return -EAGAIN;
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}
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@ -1020,8 +1028,7 @@ int spa_alsa_start(struct state *state)
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state->slaved = true;
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}
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dll_init(&state->dll, DLL_BW_MAX);
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state->old_dt = 1.0;
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init_loop(state);
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state->safety = 0.0;
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spa_log_debug(state->log, "alsa %p: start %d slave:%d", state, state->threshold, state->slaved);
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@ -1044,6 +1051,7 @@ int spa_alsa_start(struct state *state)
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}
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reset_buffers(state);
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state->alsa_sync = true;
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if (state->stream == SND_PCM_STREAM_PLAYBACK) {
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state->alsa_started = false;
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