gstreamer/plugins/elements/gstclocksync.c

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/*
* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
* 2005 Wim Taymans <wim@fluendo.com>
* Copyright (C) 2020 Jan Schmidt <jan@centricular.com>
*
* gstclocksync.c:
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:element-clocksync
* @title: clocksync
*
* Simple element that passes all buffers and buffer-lists intact, but
* synchronising them to the clock before passing.
*
* Synchronisation to the clock is on by default, but can be turned
* off by setting the 'sync' property to FALSE
*
* <refsect2>
* <title>Example launch line</title>
* |[
* gst-launch -v -m videotestsrc ! clocksync ! fakesink silent=TRUE
* ]|
* </refsect2>
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <gst/gst.h>
#include "gstclocksync.h"
#include "gstcoreelementselements.h"
GST_DEBUG_CATEGORY_STATIC (gst_clock_sync_debug);
#define GST_CAT_DEFAULT gst_clock_sync_debug
/* ClockSync args */
#define DEFAULT_SYNC TRUE
#define DEFAULT_TS_OFFSET 0
#define DEFAULT_SYNC_TO_FIRST FALSE
enum
{
PROP_0,
PROP_SYNC,
PROP_TS_OFFSET,
PROP_SYNC_TO_FIRST,
PROP_LAST
};
static GParamSpec *properties[PROP_LAST];
static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("ANY")
);
static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("ANY")
);
#define _do_init \
GST_DEBUG_CATEGORY_INIT (gst_clock_sync_debug, "clocksync", 0, "clocksync element");
#define gst_clock_sync_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstClockSync, gst_clock_sync, GST_TYPE_ELEMENT,
_do_init);
GST_ELEMENT_REGISTER_DEFINE (clocksync, "clocksync", GST_RANK_NONE,
GST_TYPE_CLOCKSYNC);
static void gst_clock_sync_finalize (GObject * object);
static void gst_clock_sync_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_clock_sync_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static gboolean gst_clock_sync_sink_event (GstPad * pad, GstObject * parent,
GstEvent * event);
static GstFlowReturn gst_clock_sync_chain (GstPad * pad, GstObject * parent,
GstBuffer * buf);
static GstFlowReturn gst_clock_sync_chain_list (GstPad * pad,
GstObject * parent, GstBufferList * buflist);
static gboolean gst_clock_sync_src_query (GstPad * pad, GstObject * parent,
GstQuery * query);
static GstStateChangeReturn gst_clocksync_change_state (GstElement * element,
GstStateChange transition);
static GstClock *gst_clocksync_provide_clock (GstElement * element);
static void
gst_clock_sync_class_init (GstClockSyncClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
gobject_class = (GObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
gobject_class->set_property = gst_clock_sync_set_property;
gobject_class->get_property = gst_clock_sync_get_property;
gobject_class->finalize = gst_clock_sync_finalize;
properties[PROP_SYNC] =
g_param_spec_boolean ("sync", "Synchronize",
"Synchronize to pipeline clock", DEFAULT_SYNC,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
properties[PROP_TS_OFFSET] =
g_param_spec_int64 ("ts-offset", "Timestamp offset for synchronisation",
"Timestamp offset in nanoseconds for synchronisation, negative for earlier sync",
G_MININT64, G_MAXINT64, DEFAULT_TS_OFFSET,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
/**
* GstClockSync:sync-to-first:
*
* When enabled, clocksync elemenet will adjust "ts-offset" value
* automatically by using given timestamp of the first buffer and running
* time of pipeline, so that clocksync element can output the first buffer
* immediately without clock waiting.
*
* Since: 1.20
*/
properties[PROP_SYNC_TO_FIRST] =
g_param_spec_boolean ("sync-to-first",
"Sync to first",
"Automatically set ts-offset based on running time of the first "
"buffer and pipeline's running time "
"(i.e., ts-offset = \"pipeline running time\" - \"buffer running time\"). "
"When enabled, clocksync element will update ts-offset on the first "
"buffer per flush event or READY to PAUSED state change. "
"This property can be useful in case that buffer timestamp does not "
"necessarily have to be synchronized with pipeline's running time, "
"but duration of the buffer through clocksync element needs to be "
"synchronized with the amount of clock time go. "
"Note that mixed use of ts-offset and this property would be racy "
"if clocksync element is running already.",
DEFAULT_SYNC_TO_FIRST, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
g_object_class_install_properties (gobject_class, PROP_LAST, properties);
gstelement_class->change_state =
GST_DEBUG_FUNCPTR (gst_clocksync_change_state);
gstelement_class->provide_clock =
GST_DEBUG_FUNCPTR (gst_clocksync_provide_clock);
gst_element_class_set_static_metadata (gstelement_class,
"ClockSync",
"Generic",
"Synchronise buffers to the clock", "Jan Schmidt <jan@centricular.com>");
gst_element_class_add_static_pad_template (gstelement_class, &srctemplate);
gst_element_class_add_static_pad_template (gstelement_class, &sinktemplate);
}
static void
gst_clock_sync_finalize (GObject * object)
{
GstClockSync *clocksync = GST_CLOCKSYNC (object);
g_cond_clear (&clocksync->blocked_cond);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_clock_sync_init (GstClockSync * clocksync)
{
clocksync->sinkpad = gst_pad_new_from_static_template (&sinktemplate, "sink");
gst_pad_set_event_function (clocksync->sinkpad,
GST_DEBUG_FUNCPTR (gst_clock_sync_sink_event));
gst_pad_set_chain_function (clocksync->sinkpad,
GST_DEBUG_FUNCPTR (gst_clock_sync_chain));
gst_pad_set_chain_list_function (clocksync->sinkpad,
GST_DEBUG_FUNCPTR (gst_clock_sync_chain_list));
GST_PAD_SET_PROXY_CAPS (clocksync->sinkpad);
gst_element_add_pad (GST_ELEMENT (clocksync), clocksync->sinkpad);
clocksync->srcpad = gst_pad_new_from_static_template (&srctemplate, "src");
gst_pad_set_query_function (clocksync->srcpad, gst_clock_sync_src_query);
GST_PAD_SET_PROXY_CAPS (clocksync->srcpad);
gst_element_add_pad (GST_ELEMENT (clocksync), clocksync->srcpad);
clocksync->ts_offset = DEFAULT_TS_OFFSET;
clocksync->sync = DEFAULT_SYNC;
clocksync->sync_to_first = DEFAULT_SYNC_TO_FIRST;
g_cond_init (&clocksync->blocked_cond);
GST_OBJECT_FLAG_SET (clocksync, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
GST_OBJECT_FLAG_SET (clocksync, GST_ELEMENT_FLAG_REQUIRE_CLOCK);
}
static void
gst_clock_sync_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstClockSync *clocksync = GST_CLOCKSYNC (object);
GstMessage *clock_message = NULL;
gboolean sync;
switch (prop_id) {
case PROP_SYNC:
clocksync->sync = g_value_get_boolean (value);
sync = g_value_get_boolean (value);
GST_OBJECT_LOCK (clocksync);
if (sync != clocksync->sync) {
clocksync->sync = sync;
if (sync) {
GST_OBJECT_FLAG_SET (clocksync, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
clock_message =
gst_message_new_clock_provide (GST_OBJECT_CAST (clocksync),
gst_system_clock_obtain (), TRUE);
} else {
GST_OBJECT_FLAG_UNSET (clocksync, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
clock_message =
gst_message_new_clock_lost (GST_OBJECT_CAST (clocksync),
gst_system_clock_obtain ());
}
}
GST_OBJECT_UNLOCK (clocksync);
if (clock_message)
gst_element_post_message (GST_ELEMENT_CAST (clocksync), clock_message);
break;
case PROP_TS_OFFSET:
clocksync->ts_offset = g_value_get_int64 (value);
break;
case PROP_SYNC_TO_FIRST:
clocksync->sync_to_first = g_value_get_boolean (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_clock_sync_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstClockSync *clocksync = GST_CLOCKSYNC (object);
switch (prop_id) {
case PROP_SYNC:
g_value_set_boolean (value, clocksync->sync);
break;
case PROP_TS_OFFSET:
g_value_set_int64 (value, clocksync->ts_offset);
break;
case PROP_SYNC_TO_FIRST:
g_value_set_boolean (value, clocksync->sync_to_first);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static GstFlowReturn
gst_clocksync_do_sync (GstClockSync * clocksync, GstClockTime running_time)
{
GstFlowReturn ret = GST_FLOW_OK;
GstClock *clock;
if (!clocksync->sync)
return GST_FLOW_OK;
if (running_time == GST_CLOCK_TIME_NONE)
return GST_FLOW_OK; /* Can't sync on an invalid time either way */
if (clocksync->segment.format != GST_FORMAT_TIME)
return GST_FLOW_OK;
GST_OBJECT_LOCK (clocksync);
if (clocksync->flushing) {
GST_OBJECT_UNLOCK (clocksync);
return GST_FLOW_FLUSHING;
}
while (clocksync->blocked && !clocksync->flushing)
g_cond_wait (&clocksync->blocked_cond, GST_OBJECT_GET_LOCK (clocksync));
if (clocksync->flushing) {
GST_OBJECT_UNLOCK (clocksync);
return GST_FLOW_FLUSHING;
}
if ((clock = GST_ELEMENT (clocksync)->clock)) {
GstClockReturn cret;
GstClockTime timestamp;
GstClockTimeDiff ts_offset = clocksync->ts_offset;
timestamp = running_time + GST_ELEMENT (clocksync)->base_time +
clocksync->upstream_latency;
if (ts_offset < 0) {
ts_offset = -ts_offset;
if (ts_offset < timestamp)
timestamp -= ts_offset;
else
timestamp = 0;
} else
timestamp += ts_offset;
/* save id if we need to unlock */
clocksync->clock_id = gst_clock_new_single_shot_id (clock, timestamp);
GST_OBJECT_UNLOCK (clocksync);
cret = gst_clock_id_wait (clocksync->clock_id, NULL);
GST_OBJECT_LOCK (clocksync);
if (clocksync->clock_id) {
gst_clock_id_unref (clocksync->clock_id);
clocksync->clock_id = NULL;
}
if (cret == GST_CLOCK_UNSCHEDULED || clocksync->flushing)
ret = GST_FLOW_FLUSHING;
}
GST_OBJECT_UNLOCK (clocksync);
return ret;
}
static gboolean
gst_clock_sync_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
{
GstClockSync *clocksync = GST_CLOCKSYNC (parent);
gboolean ret;
GST_LOG_OBJECT (clocksync, "Received %s event: %" GST_PTR_FORMAT,
GST_EVENT_TYPE_NAME (event), event);
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_SEGMENT:
/* store the event for synching */
gst_event_copy_segment (event, &clocksync->segment);
break;
case GST_EVENT_GAP:
{
GstClockTime start, dur;
if (clocksync->segment.format != GST_FORMAT_TIME)
break;
gst_event_parse_gap (event, &start, &dur);
if (GST_CLOCK_TIME_IS_VALID (start)) {
start = gst_segment_to_running_time (&clocksync->segment,
GST_FORMAT_TIME, start);
gst_clocksync_do_sync (clocksync, start);
}
break;
}
case GST_EVENT_FLUSH_START:
GST_OBJECT_LOCK (clocksync);
clocksync->flushing = TRUE;
g_cond_signal (&clocksync->blocked_cond);
if (clocksync->clock_id) {
GST_DEBUG_OBJECT (clocksync, "unlock clock wait");
gst_clock_id_unschedule (clocksync->clock_id);
}
GST_OBJECT_UNLOCK (clocksync);
break;
case GST_EVENT_FLUSH_STOP:
GST_OBJECT_LOCK (clocksync);
clocksync->flushing = FALSE;
gst_segment_init (&clocksync->segment, GST_FORMAT_UNDEFINED);
GST_OBJECT_UNLOCK (clocksync);
clocksync->is_first = TRUE;
break;
default:
break;
}
/* Always handle all events as normal: */
ret = gst_pad_event_default (pad, parent, event);
return ret;
}
static void
gst_clock_sync_update_ts_offset (GstClockSync * clocksync,
GstClockTime runtimestamp)
{
GstClock *clock;
GstClockTimeDiff ts_offset = 0;
GstClockTime running_time;
if (!clocksync->sync_to_first || !clocksync->is_first || !clocksync->sync)
return;
GST_OBJECT_LOCK (clocksync);
clock = GST_ELEMENT_CLOCK (clocksync);
if (!clock) {
GST_DEBUG_OBJECT (clocksync, "We have no clock");
GST_OBJECT_UNLOCK (clocksync);
return;
}
running_time = gst_clock_get_time (clock) -
GST_ELEMENT_CAST (clocksync)->base_time;
ts_offset = GST_CLOCK_DIFF (runtimestamp, running_time);
GST_OBJECT_UNLOCK (clocksync);
GST_DEBUG_OBJECT (clocksync, "Running time %" GST_TIME_FORMAT
", running time stamp %" GST_TIME_FORMAT ", calculated ts-offset %"
GST_STIME_FORMAT, GST_TIME_ARGS (running_time),
GST_TIME_ARGS (runtimestamp), GST_STIME_ARGS (ts_offset));
clocksync->is_first = FALSE;
if (ts_offset != clocksync->ts_offset) {
clocksync->ts_offset = ts_offset;
g_object_notify_by_pspec (G_OBJECT (clocksync), properties[PROP_TS_OFFSET]);
}
}
static GstFlowReturn
gst_clock_sync_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
{
GstClockSync *clocksync = GST_CLOCKSYNC (parent);
GstFlowReturn ret = GST_FLOW_OK;
GST_LOG_OBJECT (clocksync, "Handling buffer %" GST_PTR_FORMAT, buf);
if (clocksync->segment.format == GST_FORMAT_TIME) {
GstClockTime runtimestamp = 0;
GstClockTime rundts, runpts;
if (clocksync->segment.rate > 0.0) {
rundts = gst_segment_to_running_time (&clocksync->segment,
GST_FORMAT_TIME, GST_BUFFER_DTS (buf));
runpts = gst_segment_to_running_time (&clocksync->segment,
GST_FORMAT_TIME, GST_BUFFER_PTS (buf));
} else {
runpts = gst_segment_to_running_time (&clocksync->segment,
GST_FORMAT_TIME, GST_CLOCK_TIME_IS_VALID (buf->duration)
&& GST_CLOCK_TIME_IS_VALID (buf->pts) ? buf->pts +
buf->duration : buf->pts);
rundts = gst_segment_to_running_time (&clocksync->segment,
GST_FORMAT_TIME, GST_CLOCK_TIME_IS_VALID (buf->duration)
&& GST_CLOCK_TIME_IS_VALID (buf->dts) ? buf->dts +
buf->duration : buf->dts);
}
if (GST_CLOCK_TIME_IS_VALID (rundts))
runtimestamp = rundts;
else if (GST_CLOCK_TIME_IS_VALID (runpts))
runtimestamp = runpts;
gst_clock_sync_update_ts_offset (clocksync, runtimestamp);
ret = gst_clocksync_do_sync (clocksync, runtimestamp);
if (ret != GST_FLOW_OK) {
GST_LOG_OBJECT (clocksync,
"Interrupted while waiting on the clock. Dropping buffer.");
gst_buffer_unref (buf);
return ret;
}
}
/* Forward the buffer */
return gst_pad_push (clocksync->srcpad, buf);
}
static GstFlowReturn
gst_clock_sync_chain_list (GstPad * pad, GstObject * parent,
GstBufferList * buffer_list)
{
GstClockSync *clocksync = GST_CLOCKSYNC (parent);
GstFlowReturn ret = GST_FLOW_OK;
GstBuffer *buf;
GST_LOG_OBJECT (clocksync, "Handling buffer list %" GST_PTR_FORMAT,
buffer_list);
if (gst_buffer_list_length (buffer_list) == 0)
goto done;
buf = gst_buffer_list_get (buffer_list, 0);
if (clocksync->segment.format == GST_FORMAT_TIME) {
GstClockTime runtimestamp = 0;
GstClockTime rundts, runpts;
rundts = gst_segment_to_running_time (&clocksync->segment,
GST_FORMAT_TIME, GST_BUFFER_DTS (buf));
runpts = gst_segment_to_running_time (&clocksync->segment,
GST_FORMAT_TIME, GST_BUFFER_PTS (buf));
if (GST_CLOCK_TIME_IS_VALID (rundts))
runtimestamp = rundts;
else if (GST_CLOCK_TIME_IS_VALID (runpts))
runtimestamp = runpts;
gst_clock_sync_update_ts_offset (clocksync, runtimestamp);
ret = gst_clocksync_do_sync (clocksync, runtimestamp);
if (ret != GST_FLOW_OK) {
gst_buffer_list_unref (buffer_list);
return ret;
}
}
/* Forward the buffer list */
done:
return gst_pad_push_list (clocksync->srcpad, buffer_list);
}
static gboolean
gst_clock_sync_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
{
GstClockSync *clocksync = GST_CLOCKSYNC (parent);
gboolean res;
res = gst_pad_query_default (pad, parent, query);
switch (GST_QUERY_TYPE (query)) {
case GST_QUERY_LATENCY:{
gboolean live = FALSE;
GstClockTime min = 0, max = 0;
if (res) {
gst_query_parse_latency (query, &live, &min, &max);
if (clocksync->sync && max < min) {
GST_ELEMENT_WARNING (parent, CORE, CLOCK, (NULL),
("Impossible to configure latency upstream of clocksync sync=true:"
" max %" GST_TIME_FORMAT " < min %"
GST_TIME_FORMAT ". Add queues or other buffering elements.",
GST_TIME_ARGS (max), GST_TIME_ARGS (min)));
}
}
/* Ignore the upstream latency if it is not live */
GST_OBJECT_LOCK (clocksync);
if (live)
clocksync->upstream_latency = min;
else {
clocksync->upstream_latency = 0;
/* if upstream is non-live source, then there is no
* limit on the maximum latency */
max = -1;
}
GST_OBJECT_UNLOCK (clocksync);
GST_DEBUG_OBJECT (clocksync,
"Configured upstream latency = %" GST_TIME_FORMAT,
GST_TIME_ARGS (clocksync->upstream_latency));
gst_query_set_latency (query, live || clocksync->sync, min, max);
break;
}
default:
break;
}
return res;
}
static GstStateChangeReturn
gst_clocksync_change_state (GstElement * element, GstStateChange transition)
{
GstClockSync *clocksync = GST_CLOCKSYNC (element);
GstStateChangeReturn ret;
gboolean no_preroll = FALSE;
switch (transition) {
case GST_STATE_CHANGE_NULL_TO_READY:
break;
case GST_STATE_CHANGE_READY_TO_PAUSED:
GST_OBJECT_LOCK (clocksync);
clocksync->flushing = FALSE;
clocksync->blocked = TRUE;
GST_OBJECT_UNLOCK (clocksync);
if (clocksync->sync)
no_preroll = TRUE;
clocksync->is_first = TRUE;
break;
case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
GST_OBJECT_LOCK (clocksync);
clocksync->blocked = FALSE;
g_cond_signal (&clocksync->blocked_cond);
GST_OBJECT_UNLOCK (clocksync);
break;
case GST_STATE_CHANGE_PAUSED_TO_READY:
GST_OBJECT_LOCK (clocksync);
clocksync->flushing = TRUE;
if (clocksync->clock_id) {
GST_DEBUG_OBJECT (clocksync, "unlock clock wait");
gst_clock_id_unschedule (clocksync->clock_id);
}
clocksync->blocked = FALSE;
g_cond_signal (&clocksync->blocked_cond);
GST_OBJECT_UNLOCK (clocksync);
break;
default:
break;
}
ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
switch (transition) {
case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
GST_OBJECT_LOCK (clocksync);
clocksync->upstream_latency = 0;
clocksync->blocked = TRUE;
GST_OBJECT_UNLOCK (clocksync);
if (clocksync->sync)
no_preroll = TRUE;
break;
case GST_STATE_CHANGE_PAUSED_TO_READY:
break;
case GST_STATE_CHANGE_READY_TO_NULL:
break;
default:
break;
}
if (no_preroll && ret == GST_STATE_CHANGE_SUCCESS)
ret = GST_STATE_CHANGE_NO_PREROLL;
return ret;
}
/* FIXME: GStreamer 2.0 */
static GstClock *
gst_clocksync_provide_clock (GstElement * element)
{
GstClockSync *clocksync = GST_CLOCKSYNC (element);
if (!clocksync->sync)
return NULL;
return gst_system_clock_obtain ();
}