mirrors/pipewire
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/pipewire/pipewire.git synced 2025-10-29 05:40:27 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

alsa: improve headroom calculations

Browse source 
Make a function to recalculate the headroom and call it whenever the
resample state of the node can change.

When we are IRQ based scheduling but need to resample, we are actually
not driving the graph whit IRQ and need to adjust our period size and
headroom as if we are using timers.
This commit is contained in:
Wim Taymans 2023-10-18 14:45:47 +02:00
parent 2e066e6b1e
commit 6b8c267e91
2 changed files with 37 additions and 28 deletions
Download patch file Download diff file Expand all files Collapse all files

64
spa/plugins/alsa/alsa-pcm.c
View file

@ -1480,6 +1480,33 @@ spa_alsa_enum_format(struct state *state, int seq, uint32_t start, uint32_t num,
return res;
}
static void recalc_headroom(struct state *state)
{
uint32_t latency;
state->headroom = state->default_headroom;
if (!state->disable_tsched || state->resample) {
/* When using timers, we might miss the pointer update for batch
* devices so add some extra headroom. With IRQ, we know the pointers
* are updated when we wake up and we don't need the headroom. */
if (state->is_batch)
state->headroom += state->period_frames;
/* Add 32 extra samples of headroom to handle jitter in capture.
* For IRQ, we don't need this because when we wake up, we have
* exactly enough samples to read or write. */
if (state->stream == SND_PCM_STREAM_CAPTURE)
state->headroom = SPA_MAX(state->headroom, 32u);
}
state->headroom = SPA_MIN(state->headroom, state->buffer_frames);
latency = SPA_MAX(state->min_delay, SPA_MIN(state->max_delay, state->headroom));
if (state->position != NULL && state->rate != 0)
latency = SPA_SCALE32_UP(latency, state->position->clock.target_rate.denom, state->rate);
state->latency[state->port_direction].min_rate =
state->latency[state->port_direction].max_rate = latency;
}
int spa_alsa_set_format(struct state *state, struct spa_audio_info *fmt, uint32_t flags)
{
unsigned int rrate, rchannels, val, rscale = 1;
@ -1490,9 +1517,9 @@ int spa_alsa_set_format(struct state *state, struct spa_audio_info *fmt, uint32_
snd_pcm_access_mask_t *amask;
snd_pcm_t *hndl;
unsigned int periods;
bool match = true, planar = false, is_batch;
bool match = true, planar = false;
char spdif_params[128] = "";
uint32_t default_period, latency;
uint32_t default_period;
spa_log_debug(state->log, "opened:%d format:%d started:%d", state->opened,
state->have_format, state->started);
@ -1721,20 +1748,20 @@ int spa_alsa_set_format(struct state *state, struct spa_audio_info *fmt, uint32_
dir = 0;
period_size = state->default_period_size;
is_batch = snd_pcm_hw_params_is_batch(params) && !state->disable_batch;
state->is_batch = snd_pcm_hw_params_is_batch(params) && !state->disable_batch;
default_period = SPA_SCALE32_UP(DEFAULT_PERIOD, state->rate, DEFAULT_RATE);
default_period = flp2(2 * default_period - 1);
/* no period size specified. If we are batch or not using timers,
* use the graph duration as the period */
if (period_size == 0 && (is_batch || state->disable_tsched))
if (period_size == 0 && (state->is_batch || state->disable_tsched))
period_size = state->position ? state->position->clock.target_duration : default_period;
if (period_size == 0)
period_size = default_period;
if (!state->disable_tsched) {
if (is_batch) {
if (!state->disable_tsched || state->resample) {
if (state->is_batch) {
/* batch devices get their hw pointers updated every period. Make
* the period smaller and add one period of headroom. Limit the
* period size to our default so that we don't create too much
@ -1774,20 +1801,6 @@ int spa_alsa_set_format(struct state *state, struct spa_audio_info *fmt, uint32_
return -EIO;
}
state->headroom = state->default_headroom;
if (!state->disable_tsched) {
/* When using timers, we might miss the pointer update for batch
* devices so add some extra headroom. With IRQ, we know the pointers
* are updated when we wake up and we don't need the headroom. */
if (is_batch)
state->headroom += period_size;
/* Add 32 extra samples of headroom to handle jitter in capture.
* For IRQ, we don't need this because when we wake up, we have
* exactly enough samples to read or write. */
if (state->stream == SND_PCM_STREAM_CAPTURE)
state->headroom = SPA_MAX(state->headroom, 32u);
}
state->max_delay = state->buffer_frames / 2;
if (spa_strstartswith(state->props.device, "a52") ||
spa_strstartswith(state->props.device, "dca"))
@ -1795,15 +1808,9 @@ int spa_alsa_set_format(struct state *state, struct spa_audio_info *fmt, uint32_
else
state->min_delay = 0;
state->headroom = SPA_MIN(state->headroom, state->buffer_frames);
state->start_delay = state->default_start_delay;
latency = SPA_MAX(state->min_delay, SPA_MIN(state->max_delay, state->headroom));
if (state->position != NULL)
latency = SPA_SCALE32_UP(latency, state->position->clock.target_rate.denom, state->rate);
state->latency[state->port_direction].min_rate =
state->latency[state->port_direction].max_rate = latency;
recalc_headroom(state);
spa_log_info(state->log, "%s: format:%s access:%s-%s rate:%d channels:%d "
"buffer frames %lu, period frames %lu, periods %u, frame_size %zd "
@ -1813,7 +1820,7 @@ int spa_alsa_set_format(struct state *state, struct spa_audio_info *fmt, uint32_
planar ? "planar" : "interleaved",
state->rate, state->channels, state->buffer_frames, state->period_frames,
periods, state->frame_size, state->headroom, state->start_delay,
is_batch, !state->disable_tsched);
state->is_batch, !state->disable_tsched);
/* write the parameters to device */
CHECK(snd_pcm_hw_params(hndl, params), "set_hw_params");
@ -2339,6 +2346,7 @@ static int setup_matching(struct state *state)
state->matching = false;
state->resample = !state->pitch_elem && (((uint32_t)state->rate != state->driver_rate.denom) || state->matching);
recalc_headroom(state);
spa_log_info(state->log, "driver clock:'%s'@%d our clock:'%s'@%d matching:%d resample:%d",
state->position->clock.name, state->driver_rate.denom,

1
spa/plugins/alsa/alsa-pcm.h
View file

@ -218,6 +218,7 @@ struct state {
unsigned int sources_added:1;
unsigned int auto_link:1;
unsigned int linked:1;
unsigned int is_batch:1;
uint64_t iec958_codecs;