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Merge branch 'sklug/upstream/fix-stream-synchronization-v1' into 'master'

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RFC: Improve/fix timestamping issues with gstpipewiresrc

See merge request pipewire/pipewire!2786
This commit is contained in:
Stefan Klug 2026-05-22 17:45:57 +00:00
commit 7f17b50ae6
5 changed files with 71 additions and 85 deletions
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24
spa/plugins/libcamera/libcamera-source.cpp
View file

@ -1060,20 +1060,12 @@ void handle_completed_request(struct impl *impl, libcamera::Request *request)
const FrameMetadata &fmd = buffer->metadata();
if (impl->clock) {
double target = (double)port->info.rate.num / port->info.rate.denom;
double corr;
if (impl->dll.bw == 0.0) {
spa_dll_set_bw(&impl->dll, SPA_DLL_BW_MAX, port->info.rate.denom, port->info.rate.denom);
impl->clock->next_nsec = fmd.timestamp;
corr = 1.0;
} else {
double diff = ((double)impl->clock->next_nsec - (double)fmd.timestamp) / SPA_NSEC_PER_SEC;
double error = port->info.rate.denom * (diff - target);
corr = spa_dll_update(&impl->dll, SPA_CLAMPD(error, -128., 128.));
}
/* FIXME, we should follow the driver clock and target_ values.
* for now we ignore and use our own. */
/*
* The clock has SPA_IO_CLOCK_FLAG_NO_RATE set, so there is no
* need to update any rate specific fields.
* As libcamera uses CLOCK_MONOTONIC internally, there is no
* need to adjust the timestamps.
*/
impl->clock->target_rate = port->rate;
impl->clock->target_duration = 1;
@ -1082,8 +1074,8 @@ void handle_completed_request(struct impl *impl, libcamera::Request *request)
impl->clock->position = fmd.sequence;
impl->clock->duration = 1;
impl->clock->delay = 0;
impl->clock->rate_diff = corr;
impl->clock->next_nsec += (uint64_t) (target * SPA_NSEC_PER_SEC * corr);
impl->clock->rate_diff = 1.0;
impl->clock->next_nsec = fmd.timestamp+1;
}
if (b->h) {

23
src/gst/gstpipewireclock.c
View file

@ -22,6 +22,7 @@ gst_pipewire_clock_new (GstPipeWireStream *stream, GstClockTime last_time)
g_weak_ref_set (&clock->stream, stream);
clock->last_time = last_time;
clock->time_offset = last_time;
clock->start_time_valid = false;
return GST_CLOCK_CAST (clock);
}
@ -38,19 +39,35 @@ gst_pipewire_clock_get_internal_time (GstClock * clock)
return pclock->last_time;
now = pw_stream_get_nsec(s->pwstream);
#if 1
struct pw_time t;
if (s->pwstream == NULL ||
pw_stream_get_time_n (s->pwstream, &t, sizeof(t)) < 0 ||
t.rate.denom == 0)
return pclock->last_time;
t.rate.denom == 0) {
pclock->start_time_valid = false;
if (now < pclock->last_time)
return pclock->last_time;
return now;
}
result = gst_util_uint64_scale (t.ticks, GST_SECOND * t.rate.num, t.rate.denom);
uint64_t elapsed = gst_util_uint64_scale (t.ticks, GST_SECOND * t.rate.num, t.rate.denom);
if (!pclock->start_time_valid) {
pclock->start_time = t.now - elapsed;
pclock->start_time_valid = true;
}
result = pclock->start_time + elapsed;
result += now - t.now;
result += pclock->time_offset;
pclock->last_time = result;
if ( ABS(GST_CLOCK_DIFF(now, result)) > GST_SECOND * 5 ) {
GST_ERROR ("clock: %p Large timedrift detected. Something is wrong.", pclock);
}
GST_DEBUG ("%"PRId64", %d/%d %"PRId64" %"PRId64" %"PRId64,
t.ticks, t.rate.num, t.rate.denom, t.now, result, now);
#else

2
src/gst/gstpipewireclock.h
View file

@ -22,6 +22,8 @@ struct _GstPipeWireClock {
GWeakRef stream;
GstClockTime last_time;
GstClockTime start_time;
bool start_time_valid;
GstClockTimeDiff time_offset;
};

105
src/gst/gstpipewiresrc.c
View file

@ -116,8 +116,6 @@ static gboolean gst_pipewire_src_start (GstBaseSrc * basesrc);
static gboolean gst_pipewire_src_stop (GstBaseSrc * basesrc);
static gboolean gst_pipewire_src_event (GstBaseSrc * src, GstEvent * event);
static gboolean gst_pipewire_src_query (GstBaseSrc * src, GstQuery * query);
static void gst_pipewire_src_get_times (GstBaseSrc * basesrc, GstBuffer * buffer,
GstClockTime * start, GstClockTime * end);
static void
gst_pipewire_src_set_property (GObject * object, guint prop_id,
@ -501,7 +499,6 @@ gst_pipewire_src_class_init (GstPipeWireSrcClass * klass)
gstbasesrc_class->stop = gst_pipewire_src_stop;
gstbasesrc_class->event = gst_pipewire_src_event;
gstbasesrc_class->query = gst_pipewire_src_query;
gstbasesrc_class->get_times = gst_pipewire_src_get_times;
gstpushsrc_class->create = gst_pipewire_src_create;
GST_DEBUG_CATEGORY_INIT (pipewire_src_debug, "pipewiresrc", 0,
@ -531,7 +528,6 @@ gst_pipewire_src_init (GstPipeWireSrc * src)
src->autoconnect = DEFAULT_AUTOCONNECT;
src->min_latency = 0;
src->max_latency = GST_CLOCK_TIME_NONE;
src->last_buffer_clock_time = GST_CLOCK_TIME_NONE;
src->n_buffers = 0;
src->flushing_on_remove_buffer = FALSE;
src->on_disconnect = DEFAULT_ON_DISCONNECT;
@ -1523,40 +1519,13 @@ gst_pipewire_src_query (GstBaseSrc * src, GstQuery * query)
return res;
}
static void
gst_pipewire_src_get_times (GstBaseSrc * basesrc, GstBuffer * buffer,
GstClockTime * start, GstClockTime * end)
{
GstPipeWireSrc *pwsrc = GST_PIPEWIRE_SRC (basesrc);
/* for live sources, sync on the timestamp of the buffer */
if (gst_base_src_is_live (basesrc)) {
GstClockTime timestamp = GST_BUFFER_PTS (buffer);
if (GST_CLOCK_TIME_IS_VALID (timestamp)) {
/* get duration to calculate end time */
GstClockTime duration = GST_BUFFER_DURATION (buffer);
if (GST_CLOCK_TIME_IS_VALID (duration)) {
*end = timestamp + duration;
}
*start = timestamp;
}
} else {
*start = GST_CLOCK_TIME_NONE;
*end = GST_CLOCK_TIME_NONE;
}
GST_LOG_OBJECT (pwsrc, "start %" GST_TIME_FORMAT " (%" G_GUINT64_FORMAT
"), end %" GST_TIME_FORMAT " (%" G_GUINT64_FORMAT ")",
GST_TIME_ARGS (*start), *start, GST_TIME_ARGS (*end), *end);
}
static GstFlowReturn
gst_pipewire_src_create (GstPushSrc * psrc, GstBuffer ** buffer)
{
GstPipeWireSrc *pwsrc;
GstClockTime pts, dts, base_time;
const char *error = NULL;
GstClock *clock;
GstBuffer *buf;
gboolean update_time = FALSE, timeout = FALSE;
GstCaps *caps = NULL;
@ -1615,21 +1584,12 @@ gst_pipewire_src_create (GstPushSrc * psrc, GstBuffer ** buffer)
GST_LOG_OBJECT (pwsrc, "popped buffer %p", buf);
if (buf != NULL) {
if (pwsrc->resend_last || pwsrc->keepalive_time > 0) {
GstClock *clock;
GstBuffer *old;
old = pwsrc->last_buffer;
pwsrc->last_buffer = gst_buffer_copy (buf);
gst_buffer_unref (old);
gst_buffer_add_parent_buffer_meta (pwsrc->last_buffer, buf);
clock = gst_element_get_clock (GST_ELEMENT_CAST (pwsrc));
if (clock != NULL) {
pwsrc->last_buffer_clock_time = gst_clock_get_time (clock);
gst_object_unref (clock);
} else {
pwsrc->last_buffer_clock_time = GST_CLOCK_TIME_NONE;
}
}
break;
}
@ -1652,38 +1612,52 @@ gst_pipewire_src_create (GstPushSrc * psrc, GstBuffer ** buffer)
pw_thread_loop_unlock (pwsrc->stream->core->loop);
*buffer = buf;
clock = gst_element_get_clock (GST_ELEMENT_CAST (pwsrc));
if (update_time) {
GstClock *clock;
GstClockTime current_clock_time;
clock = gst_element_get_clock (GST_ELEMENT_CAST (pwsrc));
if (clock != NULL) {
current_clock_time = gst_clock_get_time (clock);
pts = dts = gst_clock_get_time (clock);
gst_object_unref (clock);
} else {
current_clock_time = GST_CLOCK_TIME_NONE;
pts = dts = GST_CLOCK_TIME_NONE;
}
if (GST_CLOCK_TIME_IS_VALID (current_clock_time) &&
GST_CLOCK_TIME_IS_VALID (pwsrc->last_buffer_clock_time) &&
GST_CLOCK_TIME_IS_VALID (GST_BUFFER_PTS (*buffer)) &&
GST_CLOCK_TIME_IS_VALID (GST_BUFFER_DTS (*buffer))) {
GstClockTime diff;
diff = current_clock_time - pwsrc->last_buffer_clock_time;
GST_BUFFER_PTS (*buffer) += diff;
GST_BUFFER_DTS (*buffer) += diff;
} else {
GST_BUFFER_PTS (*buffer) = GST_BUFFER_DTS (*buffer) = current_clock_time;
}
GST_LOG_OBJECT (pwsrc, "Sending keepalive buffer pts/dts: %" GST_TIME_FORMAT
" (%" G_GUINT64_FORMAT ")", GST_TIME_ARGS (current_clock_time),
current_clock_time);
GST_LOG_OBJECT (pwsrc, "Sending keepalive buffer");
} else {
pts = GST_BUFFER_PTS (*buffer);
dts = GST_BUFFER_DTS (*buffer);
}
/*
* We need to map the pipwire time to gstreamer time. If the gstreamer clock
* is provided by us, we can safely use the base_time of the element.
* Otherwise we can not assume that the gstreamer clock is CLOCK_MONOTONIC and
* must therefore fall back to our own base_time. This might introduce a bit
* of jitter.
*/
base_time = 0;
if (pwsrc->is_live) {
if (clock == pwsrc->stream->clock) {
base_time = gst_element_get_base_time (GST_ELEMENT_CAST (pwsrc));
} else {
base_time = pwsrc->pw_base_time;
}
}
if (GST_CLOCK_TIME_IS_VALID (pts))
pts = (pts >= base_time ? pts - base_time : 0);
if (GST_CLOCK_TIME_IS_VALID (dts))
dts = (dts >= base_time ? dts - base_time : 0);
GST_LOG_OBJECT (pwsrc,
"pts %" G_GUINT64_FORMAT ", dts %" G_GUINT64_FORMAT
", base-time %" GST_TIME_FORMAT " -> %" GST_TIME_FORMAT ", %" GST_TIME_FORMAT,
GST_BUFFER_PTS (*buffer), GST_BUFFER_DTS (*buffer), GST_TIME_ARGS (base_time),
GST_TIME_ARGS (pts), GST_TIME_ARGS (dts));
GST_BUFFER_PTS (*buffer) = pts;
GST_BUFFER_DTS (*buffer) = dts;
return GST_FLOW_OK;
not_negotiated:
@ -1781,6 +1755,7 @@ gst_pipewire_src_change_state (GstElement * element, GstStateChange transition)
GST_DEBUG_OBJECT (this, "activating stream");
pw_thread_loop_lock (this->stream->core->loop);
this->pw_base_time = pw_stream_get_nsec (this->stream->pwstream);
pw_stream_set_active (this->stream->pwstream, true);
/* if state have been paused for longer time, the underlying node might
* be moved from idle to suspended, which would mean format cleared via

2
src/gst/gstpipewiresrc.h
View file

@ -79,11 +79,11 @@ struct _GstPipeWireSrc {
gboolean is_live;
int64_t delay;
uint64_t pw_base_time;
GstClockTime min_latency;
GstClockTime max_latency;
GstBuffer *last_buffer;
GstClockTime last_buffer_clock_time;
enum spa_meta_videotransform_value transform_value;