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gstreamer/subprojects/gst-plugins-base/gst/playback/gststreamsynchronizer.c
Yacine Bandou 1b191d1d8d streamsynchronizer: Fix deadlock when streams have been flushed before others start 
To simplify the description, I'm assuming we only have two streams: video and audio.

For the video stream, we have the following events :
- STREAM_START => stream->wait set to true
- NEW_SEGMENT(1) => blocked waiting in gst_stream_synchronizer_wait
- FLUSH_START => unblocked
- FLUSH_STOP => stream->wait reset to false
- NEW_SEGMENT(2) => not waiting, since stream->wait is false

Then for the audio stream, we have the following events :
- STREAM_START => stream->wait set to true
- NEW_SEGMENT(2) => blocked waiting in gst_stream_synchronizer_wait for ever.

Note: The first NEW_SEGMENT event and the FLUSH_START, FLUSH_STOP events of the audio stream
are dropped before being received by the streamsynchronizer element, because the decodebin audio pad src
is not yet linked to the playsink audio pad sink.

To fix this deadlock, we don't reset stream->wait to false in the FLUSH_STOP event when it is not
waiting for the EOS of the other streams.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6887>
2024-05-23 17:51:02 +01:00

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/* GStreamer
* Copyright (C) 2010 Sebastian Dröge <sebastian.droege@collabora.co.uk>
*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gstplaybackelements.h"
#include "gststreamsynchronizer.h"
GST_DEBUG_CATEGORY_STATIC (stream_synchronizer_debug);
#define GST_CAT_DEFAULT stream_synchronizer_debug
#define GST_STREAM_SYNCHRONIZER_LOCK(obj) G_STMT_START { \
GST_TRACE_OBJECT (obj, \
"locking from thread %p", \
g_thread_self ()); \
g_mutex_lock (&GST_STREAM_SYNCHRONIZER_CAST(obj)->lock); \
GST_TRACE_OBJECT (obj, \
"locked from thread %p", \
g_thread_self ()); \
} G_STMT_END
#define GST_STREAM_SYNCHRONIZER_UNLOCK(obj) G_STMT_START { \
GST_TRACE_OBJECT (obj, \
"unlocking from thread %p", \
g_thread_self ()); \
g_mutex_unlock (&GST_STREAM_SYNCHRONIZER_CAST(obj)->lock); \
} G_STMT_END
static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src_%u",
GST_PAD_SRC,
GST_PAD_SOMETIMES,
GST_STATIC_CAPS_ANY);
static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink_%u",
GST_PAD_SINK,
GST_PAD_REQUEST,
GST_STATIC_CAPS_ANY);
#define gst_stream_synchronizer_parent_class parent_class
G_DEFINE_TYPE (GstStreamSynchronizer, gst_stream_synchronizer,
GST_TYPE_ELEMENT);
#define _do_init \
playback_element_init (plugin);
GST_ELEMENT_REGISTER_DEFINE_WITH_CODE (streamsynchronizer, "streamsynchronizer",
GST_RANK_NONE, GST_TYPE_STREAM_SYNCHRONIZER, _do_init);
typedef struct
{
GstStreamSynchronizer *transform;
guint stream_number;
GstPad *srcpad;
GstPad *sinkpad;
GstSegment segment;
gboolean wait; /* TRUE if waiting/blocking */
gboolean is_eos; /* TRUE if EOS was received */
gboolean eos_sent; /* when EOS was sent downstream */
gboolean flushing; /* set after flush-start and before flush-stop */
gboolean seen_data;
gboolean send_gap_event;
GstClockTime gap_duration;
GstStreamFlags flags;
GCond stream_finish_cond;
/* seqnum of the previously received STREAM_START
* default: G_MAXUINT32 */
guint32 stream_start_seqnum;
guint32 segment_seqnum;
guint group_id;
gint refcount;
} GstSyncStream;
static GstSyncStream *
gst_syncstream_ref (GstSyncStream * stream)
{
g_return_val_if_fail (stream != NULL, NULL);
g_atomic_int_add (&stream->refcount, 1);
return stream;
}
static void
gst_syncstream_unref (GstSyncStream * stream)
{
g_return_if_fail (stream != NULL);
g_return_if_fail (stream->refcount > 0);
if (g_atomic_int_dec_and_test (&stream->refcount))
g_free (stream);
}
G_BEGIN_DECLS
#define GST_TYPE_STREAMSYNC_PAD (gst_streamsync_pad_get_type ())
#define GST_IS_STREAMSYNC_PAD(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_STREAMSYNC_PAD))
#define GST_IS_STREAMSYNC_PAD_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_STREAMSYNC_PAD))
#define GST_STREAMSYNC_PAD(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_STREAMSYNC_PAD, GstStreamSyncPad))
#define GST_STREAMSYNC_PAD_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_STREAMSYNC_PAD, GstStreamSyncPadClass))
typedef struct _GstStreamSyncPad GstStreamSyncPad;
typedef struct _GstStreamSyncPadClass GstStreamSyncPadClass;
struct _GstStreamSyncPad
{
GstPad parent;
GstSyncStream *stream;
/* Since we need to access data associated with a pad in this
* element, it's important to manage the respective lifetimes of the
* stored pad data and the pads themselves. Pad deactivation happens
* without mutual exclusion to the use of pad data in this element.
*
* The approach here is to have the sinkpad (the request pad) hold a
* strong reference onto the srcpad (so that it stays alive until
* the last pad is destroyed). Similarly the srcpad has a weak
* reference to the sinkpad (request pad) to ensure it knows when
* the pads are destroyed, since the pad data may be requested from
* either the srcpad or the sinkpad. This avoids a nasty set of
* potential race conditions.
*
* The code is arranged so that in the srcpad, the pad pointer is
* always NULL (not used) and in the sinkpad, the otherpad is always
* NULL. */
GstPad *pad;
GWeakRef otherpad;
};
struct _GstStreamSyncPadClass
{
GstPadClass parent_class;
};
static GType gst_streamsync_pad_get_type (void);
static GstSyncStream *gst_streamsync_pad_get_stream (GstPad * pad);
G_END_DECLS
#define GST_STREAMSYNC_PAD_CAST(obj) ((GstStreamSyncPad *)obj)
G_DEFINE_TYPE (GstStreamSyncPad, gst_streamsync_pad, GST_TYPE_PAD);
static void gst_streamsync_pad_dispose (GObject * object);
static void
gst_streamsync_pad_class_init (GstStreamSyncPadClass * klass)
{
GObjectClass *gobject_class;
gobject_class = G_OBJECT_CLASS (klass);
gobject_class->dispose = gst_streamsync_pad_dispose;
}
static void
gst_streamsync_pad_init (GstStreamSyncPad * ppad)
{
}
static void
gst_streamsync_pad_dispose (GObject * object)
{
GstStreamSyncPad *spad = GST_STREAMSYNC_PAD_CAST (object);
if (GST_PAD_DIRECTION (spad) == GST_PAD_SINK)
gst_clear_object (&spad->pad);
else
g_weak_ref_clear (&spad->otherpad);
g_clear_pointer (&spad->stream, gst_syncstream_unref);
G_OBJECT_CLASS (gst_streamsync_pad_parent_class)->dispose (object);
}
static GstPad *
gst_streamsync_pad_new_from_template (GstPadTemplate * templ,
const gchar * name)
{
g_return_val_if_fail (GST_IS_PAD_TEMPLATE (templ), NULL);
return GST_PAD_CAST (g_object_new (GST_TYPE_STREAMSYNC_PAD,
"name", name, "direction", templ->direction, "template", templ,
NULL));
}
static GstPad *
gst_streamsync_pad_new_from_static_template (GstStaticPadTemplate * templ,
const gchar * name)
{
GstPad *pad;
GstPadTemplate *template;
template = gst_static_pad_template_get (templ);
pad = gst_streamsync_pad_new_from_template (template, name);
gst_object_unref (template);
return pad;
}
static GstSyncStream *
gst_streamsync_pad_get_stream (GstPad * pad)
{
GstStreamSyncPad *spad = GST_STREAMSYNC_PAD_CAST (pad);
return gst_syncstream_ref (spad->stream);
}
static GstPad *
gst_stream_get_other_pad_from_pad (GstStreamSynchronizer * self, GstPad * pad)
{
GstStreamSyncPad *spad = GST_STREAMSYNC_PAD_CAST (pad);
GstPad *opad = NULL;
if (GST_PAD_DIRECTION (pad) == GST_PAD_SINK)
opad = gst_object_ref (spad->pad);
else
opad = g_weak_ref_get (&spad->otherpad);
if (!opad)
GST_WARNING_OBJECT (pad, "Trying to get other pad after releasing");
return opad;
}
/* Generic pad functions */
static GstIterator *
gst_stream_synchronizer_iterate_internal_links (GstPad * pad,
GstObject * parent)
{
GstIterator *it = NULL;
GstPad *opad;
opad =
gst_stream_get_other_pad_from_pad (GST_STREAM_SYNCHRONIZER (parent), pad);
if (opad) {
GValue value = { 0, };
g_value_init (&value, GST_TYPE_PAD);
g_value_set_object (&value, opad);
it = gst_iterator_new_single (GST_TYPE_PAD, &value);
g_value_unset (&value);
gst_object_unref (opad);
}
return it;
}
static GstEvent *
set_event_rt_offset (GstStreamSynchronizer * self, GstPad * pad,
GstEvent * event)
{
gint64 running_time_diff;
GstSyncStream *stream;
GST_STREAM_SYNCHRONIZER_LOCK (self);
stream = gst_streamsync_pad_get_stream (pad);
running_time_diff = stream->segment.base;
gst_syncstream_unref (stream);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
if (running_time_diff != -1) {
gint64 offset;
event = gst_event_make_writable (event);
offset = gst_event_get_running_time_offset (event);
if (GST_PAD_IS_SRC (pad))
offset -= running_time_diff;
else
offset += running_time_diff;
gst_event_set_running_time_offset (event, offset);
}
return event;
}
/* srcpad functions */
static gboolean
gst_stream_synchronizer_src_event (GstPad * pad, GstObject * parent,
GstEvent * event)
{
GstStreamSynchronizer *self = GST_STREAM_SYNCHRONIZER (parent);
gboolean ret = FALSE;
GST_LOG_OBJECT (pad, "Handling event %s: %" GST_PTR_FORMAT,
GST_EVENT_TYPE_NAME (event), event);
event = set_event_rt_offset (self, pad, event);
ret = gst_pad_event_default (pad, parent, event);
return ret;
}
/* must be called with the STREAM_SYNCHRONIZER_LOCK */
static gboolean
gst_stream_synchronizer_wait (GstStreamSynchronizer * self, GstPad * pad)
{
gboolean ret = FALSE;
GstSyncStream *stream;
stream = gst_streamsync_pad_get_stream (pad);
while (!self->eos && !self->flushing) {
if (stream->flushing) {
GST_DEBUG_OBJECT (pad, "Flushing");
break;
}
if (!stream->wait) {
GST_DEBUG_OBJECT (pad, "Stream not waiting anymore");
break;
}
if (stream->send_gap_event) {
GstEvent *event;
if (!GST_CLOCK_TIME_IS_VALID (stream->segment.position)) {
GST_WARNING_OBJECT (pad, "Have no position and can't send GAP event");
stream->send_gap_event = FALSE;
continue;
}
event =
gst_event_new_gap (stream->segment.position, stream->gap_duration);
GST_DEBUG_OBJECT (pad,
"Send GAP event, position: %" GST_TIME_FORMAT " duration: %"
GST_TIME_FORMAT, GST_TIME_ARGS (stream->segment.position),
GST_TIME_ARGS (stream->gap_duration));
/* drop lock when sending GAP event, which may block in e.g. preroll */
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
ret = gst_pad_push_event (pad, event);
GST_STREAM_SYNCHRONIZER_LOCK (self);
if (!ret) {
gst_syncstream_unref (stream);
return ret;
}
stream->send_gap_event = FALSE;
/* force a check on the loop conditions as we unlocked a
* few lines above and those variables could have changed */
continue;
}
g_cond_wait (&stream->stream_finish_cond, &self->lock);
}
gst_syncstream_unref (stream);
return TRUE;
}
/* sinkpad functions */
static gboolean
gst_stream_synchronizer_sink_event (GstPad * pad, GstObject * parent,
GstEvent * event)
{
GstStreamSynchronizer *self = GST_STREAM_SYNCHRONIZER (parent);
gboolean ret = FALSE;
GST_LOG_OBJECT (pad, "Handling event %s: %" GST_PTR_FORMAT,
GST_EVENT_TYPE_NAME (event), event);
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_STREAM_START:
{
GstSyncStream *stream, *ostream;
guint32 seqnum = gst_event_get_seqnum (event);
guint group_id;
gboolean have_group_id;
GList *l;
gboolean all_wait = TRUE;
gboolean new_stream = TRUE;
have_group_id = gst_event_parse_group_id (event, &group_id);
GST_STREAM_SYNCHRONIZER_LOCK (self);
self->have_group_id &= have_group_id;
have_group_id = self->have_group_id;
self->eos = FALSE;
stream = gst_streamsync_pad_get_stream (pad);
gst_event_parse_stream_flags (event, &stream->flags);
if ((have_group_id && stream->group_id != group_id) || (!have_group_id
&& stream->stream_start_seqnum != seqnum)) {
stream->is_eos = FALSE;
stream->eos_sent = FALSE;
stream->flushing = FALSE;
stream->stream_start_seqnum = seqnum;
stream->group_id = group_id;
if (!have_group_id) {
/* Check if this belongs to a stream that is already there,
* e.g. we got the visualizations for an audio stream */
for (l = self->streams; l; l = l->next) {
ostream = l->data;
if (ostream != stream && ostream->stream_start_seqnum == seqnum
&& !ostream->wait) {
new_stream = FALSE;
break;
}
}
if (!new_stream) {
GST_DEBUG_OBJECT (pad,
"Stream %d belongs to running stream %d, no waiting",
stream->stream_number, ostream->stream_number);
stream->wait = FALSE;
gst_syncstream_unref (stream);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
break;
}
} else if (group_id == self->group_id) {
GST_DEBUG_OBJECT (pad, "Stream %d belongs to running group %d, "
"no waiting", stream->stream_number, group_id);
gst_syncstream_unref (stream);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
break;
}
GST_DEBUG_OBJECT (pad, "Stream %d changed", stream->stream_number);
stream->wait = TRUE;
for (l = self->streams; l; l = l->next) {
GstSyncStream *ostream = l->data;
all_wait = all_wait && ((ostream->flags & GST_STREAM_FLAG_SPARSE)
|| (ostream->wait && (!have_group_id
|| ostream->group_id == group_id)));
if (!all_wait)
break;
}
if (all_wait) {
gint64 position = 0;
if (have_group_id)
GST_DEBUG_OBJECT (self,
"All streams have changed to group id %u -- unblocking",
group_id);
else
GST_DEBUG_OBJECT (self, "All streams have changed -- unblocking");
self->group_id = group_id;
for (l = self->streams; l; l = l->next) {
GstSyncStream *ostream = l->data;
gint64 stop_running_time;
gint64 position_running_time;
ostream->wait = FALSE;
if (ostream->segment.format == GST_FORMAT_TIME) {
if (ostream->segment.rate > 0)
stop_running_time =
gst_segment_to_running_time (&ostream->segment,
GST_FORMAT_TIME, ostream->segment.stop);
else
stop_running_time =
gst_segment_to_running_time (&ostream->segment,
GST_FORMAT_TIME, ostream->segment.start);
position_running_time =
gst_segment_to_running_time (&ostream->segment,
GST_FORMAT_TIME, ostream->segment.position);
position_running_time =
MAX (position_running_time, stop_running_time);
if (ostream->segment.rate > 0)
position_running_time -=
gst_segment_to_running_time (&ostream->segment,
GST_FORMAT_TIME, ostream->segment.start);
else
position_running_time -=
gst_segment_to_running_time (&ostream->segment,
GST_FORMAT_TIME, ostream->segment.stop);
position_running_time = MAX (0, position_running_time);
position = MAX (position, position_running_time);
}
}
self->group_start_time += position;
GST_DEBUG_OBJECT (self, "New group start time: %" GST_TIME_FORMAT,
GST_TIME_ARGS (self->group_start_time));
for (l = self->streams; l; l = l->next) {
GstSyncStream *ostream = l->data;
ostream->wait = FALSE;
g_cond_broadcast (&ostream->stream_finish_cond);
}
}
}
gst_syncstream_unref (stream);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
break;
}
case GST_EVENT_SEGMENT:{
GstSyncStream *stream;
GstSegment segment;
gst_event_copy_segment (event, &segment);
GST_STREAM_SYNCHRONIZER_LOCK (self);
gst_stream_synchronizer_wait (self, pad);
if (self->shutdown) {
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
gst_event_unref (event);
goto done;
}
stream = gst_streamsync_pad_get_stream (pad);
if (segment.format == GST_FORMAT_TIME) {
GST_DEBUG_OBJECT (pad,
"New stream, updating base from %" GST_TIME_FORMAT " to %"
GST_TIME_FORMAT, GST_TIME_ARGS (segment.base),
GST_TIME_ARGS (segment.base + self->group_start_time));
segment.base += self->group_start_time;
GST_DEBUG_OBJECT (pad, "Segment was: %" GST_SEGMENT_FORMAT,
&stream->segment);
gst_segment_copy_into (&segment, &stream->segment);
GST_DEBUG_OBJECT (pad, "Segment now is: %" GST_SEGMENT_FORMAT,
&stream->segment);
stream->segment_seqnum = gst_event_get_seqnum (event);
GST_DEBUG_OBJECT (pad, "Stream start running time: %" GST_TIME_FORMAT,
GST_TIME_ARGS (stream->segment.base));
{
GstEvent *tmpev;
tmpev = gst_event_new_segment (&stream->segment);
gst_event_set_seqnum (tmpev, stream->segment_seqnum);
gst_event_unref (event);
event = tmpev;
}
} else if (stream) {
GST_WARNING_OBJECT (pad, "Non-TIME segment: %s",
gst_format_get_name (segment.format));
gst_segment_init (&stream->segment, GST_FORMAT_UNDEFINED);
}
gst_syncstream_unref (stream);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
break;
}
case GST_EVENT_FLUSH_START:{
GstSyncStream *stream;
GST_STREAM_SYNCHRONIZER_LOCK (self);
stream = gst_streamsync_pad_get_stream (pad);
self->eos = FALSE;
GST_DEBUG_OBJECT (pad, "Flushing streams");
stream->flushing = TRUE;
g_cond_broadcast (&stream->stream_finish_cond);
gst_syncstream_unref (stream);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
break;
}
case GST_EVENT_FLUSH_STOP:{
GstSyncStream *stream;
GList *l;
GstClockTime new_group_start_time = 0;
gboolean reset_time;
gst_event_parse_flush_stop (event, &reset_time);
GST_STREAM_SYNCHRONIZER_LOCK (self);
stream = gst_streamsync_pad_get_stream (pad);
if (reset_time) {
GST_DEBUG_OBJECT (pad, "Resetting segment for stream %d",
stream->stream_number);
gst_segment_init (&stream->segment, GST_FORMAT_UNDEFINED);
}
if (stream->is_eos) {
stream->wait = FALSE;
stream->is_eos = FALSE;
}
stream->eos_sent = FALSE;
stream->flushing = FALSE;
g_cond_broadcast (&stream->stream_finish_cond);
if (reset_time) {
for (l = self->streams; l; l = l->next) {
GstSyncStream *ostream = l->data;
GstClockTime start_running_time;
if (ostream == stream || ostream->flushing)
continue;
if (ostream->segment.format == GST_FORMAT_TIME) {
if (ostream->segment.rate > 0)
start_running_time =
gst_segment_to_running_time (&ostream->segment,
GST_FORMAT_TIME, ostream->segment.start);
else
start_running_time =
gst_segment_to_running_time (&ostream->segment,
GST_FORMAT_TIME, ostream->segment.stop);
new_group_start_time =
MAX (new_group_start_time, start_running_time);
}
}
GST_DEBUG_OBJECT (pad,
"Updating group start time from %" GST_TIME_FORMAT " to %"
GST_TIME_FORMAT, GST_TIME_ARGS (self->group_start_time),
GST_TIME_ARGS (new_group_start_time));
self->group_start_time = new_group_start_time;
}
gst_syncstream_unref (stream);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
break;
}
/* unblocking EOS wait when track switch. */
case GST_EVENT_CUSTOM_DOWNSTREAM_OOB:{
if (gst_event_has_name (event, "playsink-custom-video-flush")
|| gst_event_has_name (event, "playsink-custom-audio-flush")
|| gst_event_has_name (event, "playsink-custom-subtitle-flush")) {
GstSyncStream *stream;
GST_STREAM_SYNCHRONIZER_LOCK (self);
stream = gst_streamsync_pad_get_stream (pad);
stream->is_eos = FALSE;
stream->eos_sent = FALSE;
stream->wait = FALSE;
g_cond_broadcast (&stream->stream_finish_cond);
gst_syncstream_unref (stream);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
}
break;
}
case GST_EVENT_EOS:{
GstSyncStream *stream;
GList *l;
gboolean all_eos = TRUE;
gboolean seen_data;
GSList *pads = NULL;
GstPad *srcpad;
GstClockTime timestamp;
guint32 seqnum;
GST_STREAM_SYNCHRONIZER_LOCK (self);
stream = gst_streamsync_pad_get_stream (pad);
GST_DEBUG_OBJECT (pad, "Have EOS for stream %d", stream->stream_number);
stream->is_eos = TRUE;
seen_data = stream->seen_data;
srcpad = gst_object_ref (stream->srcpad);
seqnum = stream->segment_seqnum;
if (seen_data && stream->segment.position != -1)
timestamp = stream->segment.position;
else if (stream->segment.rate < 0.0 || stream->segment.stop == -1)
timestamp = stream->segment.start;
else
timestamp = stream->segment.stop;
stream->segment.position = timestamp;
for (l = self->streams; l; l = l->next) {
GstSyncStream *ostream = l->data;
all_eos = all_eos && ostream->is_eos;
if (!all_eos)
break;
}
if (all_eos) {
GST_DEBUG_OBJECT (self, "All streams are EOS -- forwarding");
self->eos = TRUE;
for (l = self->streams; l; l = l->next) {
GstSyncStream *ostream = l->data;
/* local snapshot of current pads */
gst_object_ref (ostream->srcpad);
pads = g_slist_prepend (pads, ostream->srcpad);
}
}
if (pads) {
GstPad *pad;
GSList *epad;
GstSyncStream *ostream;
ret = TRUE;
epad = pads;
while (epad) {
pad = epad->data;
ostream = gst_streamsync_pad_get_stream (pad);
g_cond_broadcast (&ostream->stream_finish_cond);
gst_syncstream_unref (ostream);
gst_object_unref (pad);
epad = g_slist_next (epad);
}
g_slist_free (pads);
} else {
if (seen_data) {
stream->send_gap_event = TRUE;
stream->gap_duration = GST_CLOCK_TIME_NONE;
stream->wait = TRUE;
ret = gst_stream_synchronizer_wait (self, srcpad);
}
}
/* send eos if haven't seen data. seen_data will be true if data buffer
* of the track have received in anytime. sink is ready if seen_data is
* true, so can send GAP event. Will send EOS if sink isn't ready. The
* scenario for the case is one track haven't any media data and then
* send EOS. Or no any valid media data in one track, so decoder can't
* get valid CAPS for the track. sink can't ready without received CAPS.*/
if (!seen_data || self->eos) {
GstEvent *topush;
GST_DEBUG_OBJECT (pad, "send EOS event");
/* drop lock when sending eos, which may block in e.g. preroll */
topush = gst_event_new_eos ();
gst_event_set_seqnum (topush, seqnum);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
ret = gst_pad_push_event (srcpad, topush);
GST_STREAM_SYNCHRONIZER_LOCK (self);
stream = gst_streamsync_pad_get_stream (pad);
stream->eos_sent = TRUE;
gst_syncstream_unref (stream);
}
gst_object_unref (srcpad);
gst_event_unref (event);
gst_syncstream_unref (stream);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
goto done;
}
default:
break;
}
event = set_event_rt_offset (self, pad, event);
ret = gst_pad_event_default (pad, parent, event);
done:
return ret;
}
static GstFlowReturn
gst_stream_synchronizer_sink_chain (GstPad * pad, GstObject * parent,
GstBuffer * buffer)
{
GstStreamSynchronizer *self = GST_STREAM_SYNCHRONIZER (parent);
GstPad *opad;
GstFlowReturn ret = GST_FLOW_ERROR;
GstSyncStream *stream;
GstClockTime duration = GST_CLOCK_TIME_NONE;
GstClockTime timestamp = GST_CLOCK_TIME_NONE;
GstClockTime timestamp_end = GST_CLOCK_TIME_NONE;
GST_LOG_OBJECT (pad, "Handling buffer %p: size=%" G_GSIZE_FORMAT
", timestamp=%" GST_TIME_FORMAT " duration=%" GST_TIME_FORMAT
" offset=%" G_GUINT64_FORMAT " offset_end=%" G_GUINT64_FORMAT,
buffer, gst_buffer_get_size (buffer),
GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buffer)),
GST_TIME_ARGS (GST_BUFFER_DURATION (buffer)),
GST_BUFFER_OFFSET (buffer), GST_BUFFER_OFFSET_END (buffer));
timestamp = GST_BUFFER_TIMESTAMP (buffer);
duration = GST_BUFFER_DURATION (buffer);
if (GST_CLOCK_TIME_IS_VALID (timestamp)
&& GST_CLOCK_TIME_IS_VALID (duration))
timestamp_end = timestamp + duration;
GST_STREAM_SYNCHRONIZER_LOCK (self);
stream = gst_streamsync_pad_get_stream (pad);
stream->seen_data = TRUE;
if (stream->segment.format == GST_FORMAT_TIME
&& GST_CLOCK_TIME_IS_VALID (timestamp)) {
GST_LOG_OBJECT (pad,
"Updating position from %" GST_TIME_FORMAT " to %" GST_TIME_FORMAT,
GST_TIME_ARGS (stream->segment.position), GST_TIME_ARGS (timestamp));
if (stream->segment.rate > 0.0)
stream->segment.position = timestamp;
else
stream->segment.position = timestamp_end;
}
gst_syncstream_unref (stream);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
opad = gst_stream_get_other_pad_from_pad (self, pad);
if (opad) {
ret = gst_pad_push (opad, buffer);
gst_object_unref (opad);
}
GST_LOG_OBJECT (pad, "Push returned: %s", gst_flow_get_name (ret));
if (ret == GST_FLOW_OK) {
GList *l;
GST_STREAM_SYNCHRONIZER_LOCK (self);
stream = gst_streamsync_pad_get_stream (pad);
if (stream->segment.format == GST_FORMAT_TIME) {
GstClockTime position;
if (stream->segment.rate > 0.0)
position = timestamp_end;
else
position = timestamp;
if (GST_CLOCK_TIME_IS_VALID (position)) {
GST_LOG_OBJECT (pad,
"Updating position from %" GST_TIME_FORMAT " to %" GST_TIME_FORMAT,
GST_TIME_ARGS (stream->segment.position), GST_TIME_ARGS (position));
stream->segment.position = position;
}
}
/* Advance EOS streams if necessary. For non-EOS
* streams the demuxers should already do this! */
if (!GST_CLOCK_TIME_IS_VALID (timestamp_end) &&
GST_CLOCK_TIME_IS_VALID (timestamp)) {
timestamp_end = timestamp + GST_SECOND;
}
for (l = self->streams; l; l = l->next) {
GstSyncStream *ostream = l->data;
gint64 position;
if (!ostream->is_eos || ostream->eos_sent ||
ostream->segment.format != GST_FORMAT_TIME)
continue;
if (ostream->segment.position != -1)
position = ostream->segment.position;
else
position = ostream->segment.start;
/* Is there a 1 second lag? */
if (position != -1 && GST_CLOCK_TIME_IS_VALID (timestamp_end) &&
position + GST_SECOND < timestamp_end) {
gint64 new_start;
new_start = timestamp_end - GST_SECOND;
GST_DEBUG_OBJECT (ostream->sinkpad,
"Advancing stream %u from %" GST_TIME_FORMAT " to %"
GST_TIME_FORMAT, ostream->stream_number, GST_TIME_ARGS (position),
GST_TIME_ARGS (new_start));
ostream->segment.position = new_start;
ostream->send_gap_event = TRUE;
ostream->gap_duration = new_start - position;
g_cond_broadcast (&ostream->stream_finish_cond);
}
}
gst_syncstream_unref (stream);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
}
return ret;
}
/* Must be called with lock! */
static GstPad *
gst_stream_synchronizer_new_pad (GstStreamSynchronizer * sync)
{
GstSyncStream *stream = NULL;
GstStreamSyncPad *sinkpad, *srcpad;
gchar *tmp;
stream = g_new0 (GstSyncStream, 1);
stream->transform = sync;
stream->stream_number = sync->current_stream_number;
g_cond_init (&stream->stream_finish_cond);
stream->stream_start_seqnum = G_MAXUINT32;
stream->segment_seqnum = G_MAXUINT32;
stream->group_id = G_MAXUINT;
stream->seen_data = FALSE;
stream->send_gap_event = FALSE;
stream->refcount = 1;
tmp = g_strdup_printf ("sink_%u", sync->current_stream_number);
stream->sinkpad =
gst_streamsync_pad_new_from_static_template (&sinktemplate, tmp);
g_free (tmp);
GST_STREAMSYNC_PAD_CAST (stream->sinkpad)->stream =
gst_syncstream_ref (stream);
gst_pad_set_iterate_internal_links_function (stream->sinkpad,
GST_DEBUG_FUNCPTR (gst_stream_synchronizer_iterate_internal_links));
gst_pad_set_event_function (stream->sinkpad,
GST_DEBUG_FUNCPTR (gst_stream_synchronizer_sink_event));
gst_pad_set_chain_function (stream->sinkpad,
GST_DEBUG_FUNCPTR (gst_stream_synchronizer_sink_chain));
GST_PAD_SET_PROXY_CAPS (stream->sinkpad);
GST_PAD_SET_PROXY_ALLOCATION (stream->sinkpad);
GST_PAD_SET_PROXY_SCHEDULING (stream->sinkpad);
tmp = g_strdup_printf ("src_%u", sync->current_stream_number);
stream->srcpad =
gst_streamsync_pad_new_from_static_template (&srctemplate, tmp);
g_free (tmp);
GST_STREAMSYNC_PAD_CAST (stream->srcpad)->stream =
gst_syncstream_ref (stream);
sinkpad = GST_STREAMSYNC_PAD_CAST (stream->sinkpad);
srcpad = GST_STREAMSYNC_PAD_CAST (stream->srcpad);
/* Hold a strong reference from the sink (request pad) to the src to
* ensure a predicatable destruction order */
sinkpad->pad = gst_object_ref (srcpad);
/* And a weak reference from the src to the sink, to know when pad
* release is occuring, and to ensure we do not try and take
* references to inactive / destructing streams. */
g_weak_ref_init (&srcpad->otherpad, stream->sinkpad);
gst_pad_set_iterate_internal_links_function (stream->srcpad,
GST_DEBUG_FUNCPTR (gst_stream_synchronizer_iterate_internal_links));
gst_pad_set_event_function (stream->srcpad,
GST_DEBUG_FUNCPTR (gst_stream_synchronizer_src_event));
GST_PAD_SET_PROXY_CAPS (stream->srcpad);
GST_PAD_SET_PROXY_ALLOCATION (stream->srcpad);
GST_PAD_SET_PROXY_SCHEDULING (stream->srcpad);
gst_segment_init (&stream->segment, GST_FORMAT_UNDEFINED);
GST_STREAM_SYNCHRONIZER_UNLOCK (sync);
/* Add pads and activate unless we're going to NULL */
g_rec_mutex_lock (GST_STATE_GET_LOCK (sync));
if (GST_STATE_TARGET (sync) != GST_STATE_NULL) {
gst_pad_set_active (stream->srcpad, TRUE);
gst_pad_set_active (stream->sinkpad, TRUE);
}
gst_element_add_pad (GST_ELEMENT_CAST (sync), stream->srcpad);
gst_element_add_pad (GST_ELEMENT_CAST (sync), stream->sinkpad);
g_rec_mutex_unlock (GST_STATE_GET_LOCK (sync));
GST_STREAM_SYNCHRONIZER_LOCK (sync);
sync->streams = g_list_prepend (sync->streams, g_steal_pointer (&stream));
sync->current_stream_number++;
return GST_PAD_CAST (sinkpad);
}
/* GstElement vfuncs */
static GstPad *
gst_stream_synchronizer_request_new_pad (GstElement * element,
GstPadTemplate * temp, const gchar * name, const GstCaps * caps)
{
GstStreamSynchronizer *self = GST_STREAM_SYNCHRONIZER (element);
GstPad *request_pad;
GST_STREAM_SYNCHRONIZER_LOCK (self);
GST_DEBUG_OBJECT (self, "Requesting new pad for stream %d",
self->current_stream_number);
request_pad = gst_stream_synchronizer_new_pad (self);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
return request_pad;
}
/* Must be called with lock! */
static void
gst_stream_synchronizer_release_stream (GstStreamSynchronizer * self,
GstSyncStream * stream)
{
GList *l;
GST_DEBUG_OBJECT (self, "Releasing stream %d", stream->stream_number);
for (l = self->streams; l; l = l->next) {
if (l->data == stream) {
self->streams = g_list_delete_link (self->streams, l);
break;
}
}
g_assert (l != NULL);
if (self->streams == NULL) {
self->have_group_id = TRUE;
self->group_id = G_MAXUINT;
}
/* we can drop the lock, since stream exists now only local.
* Moreover, we should drop, to prevent deadlock with STREAM_LOCK
* (due to reverse lock order) when deactivating pads */
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
gst_pad_set_active (stream->srcpad, FALSE);
gst_element_remove_pad (GST_ELEMENT_CAST (self), stream->srcpad);
gst_pad_set_active (stream->sinkpad, FALSE);
gst_element_remove_pad (GST_ELEMENT_CAST (self), stream->sinkpad);
g_cond_clear (&stream->stream_finish_cond);
/* Release the ref maintaining validity in the streams list */
gst_syncstream_unref (stream);
/* NOTE: In theory we have to check here if all streams
* are EOS but the one that was removed wasn't and then
* send EOS downstream. But due to the way how playsink
* works this is not necessary and will only cause problems
* for gapless playback. playsink will only add/remove pads
* when it's reconfigured, which happens when the streams
* change
*/
/* lock for good measure, since the caller had it */
GST_STREAM_SYNCHRONIZER_LOCK (self);
}
static void
gst_stream_synchronizer_release_pad (GstElement * element, GstPad * pad)
{
GstStreamSynchronizer *self = GST_STREAM_SYNCHRONIZER (element);
GstSyncStream *stream;
GST_STREAM_SYNCHRONIZER_LOCK (self);
stream = gst_streamsync_pad_get_stream (pad);
g_assert (stream->sinkpad == pad);
gst_stream_synchronizer_release_stream (self, stream);
gst_syncstream_unref (stream);
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
}
static GstStateChangeReturn
gst_stream_synchronizer_change_state (GstElement * element,
GstStateChange transition)
{
GstStreamSynchronizer *self = GST_STREAM_SYNCHRONIZER (element);
GstStateChangeReturn ret;
switch (transition) {
case GST_STATE_CHANGE_NULL_TO_READY:
GST_DEBUG_OBJECT (self, "State change NULL->READY");
self->shutdown = FALSE;
break;
case GST_STATE_CHANGE_READY_TO_PAUSED:
GST_DEBUG_OBJECT (self, "State change READY->PAUSED");
self->group_start_time = 0;
self->have_group_id = TRUE;
self->group_id = G_MAXUINT;
self->shutdown = FALSE;
self->flushing = FALSE;
self->eos = FALSE;
break;
case GST_STATE_CHANGE_PAUSED_TO_READY:{
GList *l;
GST_DEBUG_OBJECT (self, "State change PAUSED->READY");
GST_STREAM_SYNCHRONIZER_LOCK (self);
self->flushing = TRUE;
self->shutdown = TRUE;
for (l = self->streams; l; l = l->next) {
GstSyncStream *ostream = l->data;
g_cond_broadcast (&ostream->stream_finish_cond);
}
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
}
default:
break;
}
ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
GST_DEBUG_OBJECT (self, "Base class state changed returned: %d", ret);
if (G_UNLIKELY (ret != GST_STATE_CHANGE_SUCCESS))
return ret;
switch (transition) {
case GST_STATE_CHANGE_PLAYING_TO_PAUSED:{
GList *l;
GST_DEBUG_OBJECT (self, "State change PLAYING->PAUSED");
GST_STREAM_SYNCHRONIZER_LOCK (self);
for (l = self->streams; l; l = l->next) {
GstSyncStream *stream = l->data;
/* send GAP event to sink to finished pre-roll. The reason is function
* chain () will be blocked on pad_push (), so can't trigger the track
* which reach EOS to send GAP event. */
if (stream->is_eos && !stream->eos_sent) {
stream->send_gap_event = TRUE;
stream->gap_duration = GST_CLOCK_TIME_NONE;
g_cond_broadcast (&stream->stream_finish_cond);
}
}
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
break;
}
case GST_STATE_CHANGE_PAUSED_TO_READY:{
GList *l;
GST_DEBUG_OBJECT (self, "State change PAUSED->READY");
self->group_start_time = 0;
GST_STREAM_SYNCHRONIZER_LOCK (self);
for (l = self->streams; l; l = l->next) {
GstSyncStream *stream = l->data;
gst_segment_init (&stream->segment, GST_FORMAT_UNDEFINED);
stream->gap_duration = GST_CLOCK_TIME_NONE;
stream->wait = FALSE;
stream->is_eos = FALSE;
stream->eos_sent = FALSE;
stream->flushing = FALSE;
stream->send_gap_event = FALSE;
}
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
break;
}
case GST_STATE_CHANGE_READY_TO_NULL:{
GST_DEBUG_OBJECT (self, "State change READY->NULL");
GST_STREAM_SYNCHRONIZER_LOCK (self);
self->current_stream_number = 0;
GST_STREAM_SYNCHRONIZER_UNLOCK (self);
break;
}
default:
break;
}
return ret;
}
/* GObject vfuncs */
static void
gst_stream_synchronizer_finalize (GObject * object)
{
GstStreamSynchronizer *self = GST_STREAM_SYNCHRONIZER (object);
g_mutex_clear (&self->lock);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
/* GObject type initialization */
static void
gst_stream_synchronizer_init (GstStreamSynchronizer * self)
{
g_mutex_init (&self->lock);
}
static void
gst_stream_synchronizer_class_init (GstStreamSynchronizerClass * klass)
{
GObjectClass *gobject_class = (GObjectClass *) klass;
GstElementClass *element_class = (GstElementClass *) klass;
gobject_class->finalize = gst_stream_synchronizer_finalize;
gst_element_class_add_static_pad_template (element_class, &srctemplate);
gst_element_class_add_static_pad_template (element_class, &sinktemplate);
gst_element_class_set_static_metadata (element_class,
"Stream Synchronizer", "Generic",
"Synchronizes a group of streams to have equal durations and starting points",
"Sebastian Dröge <sebastian.droege@collabora.co.uk>");
element_class->change_state =
GST_DEBUG_FUNCPTR (gst_stream_synchronizer_change_state);
element_class->request_new_pad =
GST_DEBUG_FUNCPTR (gst_stream_synchronizer_request_new_pad);
element_class->release_pad =
GST_DEBUG_FUNCPTR (gst_stream_synchronizer_release_pad);
GST_DEBUG_CATEGORY_INIT (stream_synchronizer_debug,
"streamsynchronizer", 0, "Stream Synchronizer");
}
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