/* GStreamer concat element * * Copyright (c) 2014 Sebastian Dröge * * 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-concat * @see_also: #GstFunnel * * Concatenates streams together to one continous stream. * * All streams but the current one are blocked until the current one * finished with %GST_EVENT_EOS. Then the next stream is enabled, while * keeping the running time continous for %GST_FORMAT_TIME segments or * keeping the segment continous for %GST_FORMAT_BYTES segments. * * Streams are switched in the order in which the sinkpads were requested. * * By default, the stream segment's base values are adjusted to ensure * the segment transitions between streams are continuous. In some cases, * it may be desirable to turn off these adjustments (for example, because * another downstream element like a streamsynchronizer adjusts the base * values on its own). The adjust-value property can be used for this purpose. * * * Example launch line * |[ * gst-launch-1.0 concat name=c ! xvimagesink videotestsrc num-buffers=100 ! c. videotestsrc num-buffers=100 pattern=ball ! c. * ]| Plays two video streams one after another. * */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include "gstconcat.h" GST_DEBUG_CATEGORY_STATIC (gst_concat_debug); #define GST_CAT_DEFAULT gst_concat_debug G_GNUC_INTERNAL GType gst_concat_pad_get_type (void); #define GST_TYPE_CONCAT_PAD (gst_concat_pad_get_type()) #define GST_CONCAT_PAD(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_CONCAT_PAD, GstConcatPad)) #define GST_CONCAT_PAD_CAST(obj) ((GstConcatPad *)(obj)) #define GST_CONCAT_PAD_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_CONCAT_PAD, GstConcatPadClass)) #define GST_IS_CONCAT_PAD(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_CONCAT_PAD)) #define GST_IS_CONCAT_PAD_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_CONCAT_PAD)) typedef struct _GstConcatPad GstConcatPad; typedef struct _GstConcatPadClass GstConcatPadClass; struct _GstConcatPad { GstPad parent; GstSegment segment; /* Protected by the concat lock */ gboolean flushing; }; struct _GstConcatPadClass { GstPadClass parent; }; G_DEFINE_TYPE (GstConcatPad, gst_concat_pad, GST_TYPE_PAD); static void gst_concat_pad_class_init (GstConcatPadClass * klass) { } static void gst_concat_pad_init (GstConcatPad * self) { gst_segment_init (&self->segment, GST_FORMAT_UNDEFINED); self->flushing = FALSE; } static GstStaticPadTemplate concat_sink_template = GST_STATIC_PAD_TEMPLATE ("sink_%u", GST_PAD_SINK, GST_PAD_REQUEST, GST_STATIC_CAPS_ANY); static GstStaticPadTemplate concat_src_template = GST_STATIC_PAD_TEMPLATE ("src", GST_PAD_SRC, GST_PAD_ALWAYS, GST_STATIC_CAPS_ANY); enum { PROP_0, PROP_ACTIVE_PAD, PROP_ADJUST_BASE }; #define DEFAULT_ADJUST_BASE TRUE #define _do_init \ GST_DEBUG_CATEGORY_INIT (gst_concat_debug, "concat", 0, "concat element"); #define gst_concat_parent_class parent_class G_DEFINE_TYPE_WITH_CODE (GstConcat, gst_concat, GST_TYPE_ELEMENT, _do_init); static void gst_concat_dispose (GObject * object); static void gst_concat_finalize (GObject * object); static void gst_concat_get_property (GObject * object, guint prop_id, GValue * value, GParamSpec * pspec); static void gst_concat_set_property (GObject * object, guint prop_id, const GValue * value, GParamSpec * pspec); static GstStateChangeReturn gst_concat_change_state (GstElement * element, GstStateChange transition); static GstPad *gst_concat_request_new_pad (GstElement * element, GstPadTemplate * templ, const gchar * name, const GstCaps * caps); static void gst_concat_release_pad (GstElement * element, GstPad * pad); static GstFlowReturn gst_concat_sink_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer); static gboolean gst_concat_sink_event (GstPad * pad, GstObject * parent, GstEvent * event); static gboolean gst_concat_sink_query (GstPad * pad, GstObject * parent, GstQuery * query); static gboolean gst_concat_src_event (GstPad * pad, GstObject * parent, GstEvent * event); static gboolean gst_concat_src_query (GstPad * pad, GstObject * parent, GstQuery * query); static gboolean gst_concat_switch_pad (GstConcat * self); static void gst_concat_notify_active_pad (GstConcat * self); static GParamSpec *pspec_active_pad = NULL; static void gst_concat_class_init (GstConcatClass * klass) { GObjectClass *gobject_class = G_OBJECT_CLASS (klass); GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass); gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_concat_dispose); gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_concat_finalize); gobject_class->get_property = gst_concat_get_property; gobject_class->set_property = gst_concat_set_property; pspec_active_pad = g_param_spec_object ("active-pad", "Active pad", "Currently active src pad", GST_TYPE_PAD, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS); g_object_class_install_property (gobject_class, PROP_ACTIVE_PAD, pspec_active_pad); g_object_class_install_property (gobject_class, PROP_ADJUST_BASE, g_param_spec_boolean ("adjust-base", "Adjust segment base", "Adjust the base value of segments to ensure they are adjacent", DEFAULT_ADJUST_BASE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)); gst_element_class_set_static_metadata (gstelement_class, "Concat", "Generic", "Concatenate multiple streams", "Sebastian Dröge "); gst_element_class_add_pad_template (gstelement_class, gst_static_pad_template_get (&concat_sink_template)); gst_element_class_add_pad_template (gstelement_class, gst_static_pad_template_get (&concat_src_template)); gstelement_class->request_new_pad = GST_DEBUG_FUNCPTR (gst_concat_request_new_pad); gstelement_class->release_pad = GST_DEBUG_FUNCPTR (gst_concat_release_pad); gstelement_class->change_state = GST_DEBUG_FUNCPTR (gst_concat_change_state); } static void gst_concat_init (GstConcat * self) { g_mutex_init (&self->lock); g_cond_init (&self->cond); self->srcpad = gst_pad_new_from_static_template (&concat_src_template, "src"); gst_pad_set_event_function (self->srcpad, GST_DEBUG_FUNCPTR (gst_concat_src_event)); gst_pad_set_query_function (self->srcpad, GST_DEBUG_FUNCPTR (gst_concat_src_query)); gst_pad_use_fixed_caps (self->srcpad); gst_element_add_pad (GST_ELEMENT (self), self->srcpad); self->adjust_base = DEFAULT_ADJUST_BASE; } static void gst_concat_dispose (GObject * object) { GstConcat *self = GST_CONCAT (object); GList *item; gst_object_replace ((GstObject **) & self->current_sinkpad, NULL); restart: for (item = GST_ELEMENT_PADS (object); item; item = g_list_next (item)) { GstPad *pad = GST_PAD (item->data); if (GST_PAD_IS_SINK (pad)) { gst_element_release_request_pad (GST_ELEMENT (object), pad); goto restart; } } G_OBJECT_CLASS (parent_class)->dispose (object); } static void gst_concat_finalize (GObject * object) { GstConcat *self = GST_CONCAT (object); g_mutex_clear (&self->lock); g_cond_clear (&self->cond); G_OBJECT_CLASS (parent_class)->finalize (object); } static void gst_concat_get_property (GObject * object, guint prop_id, GValue * value, GParamSpec * pspec) { GstConcat *self = GST_CONCAT (object); switch (prop_id) { case PROP_ACTIVE_PAD:{ g_mutex_lock (&self->lock); g_value_set_object (value, self->current_sinkpad); g_mutex_unlock (&self->lock); break; } case PROP_ADJUST_BASE:{ g_mutex_lock (&self->lock); g_value_set_boolean (value, self->adjust_base); g_mutex_unlock (&self->lock); break; } default: G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); break; } } static void gst_concat_set_property (GObject * object, guint prop_id, const GValue * value, GParamSpec * pspec) { GstConcat *self = GST_CONCAT (object); switch (prop_id) { case PROP_ADJUST_BASE:{ g_mutex_lock (&self->lock); self->adjust_base = g_value_get_boolean (value); g_mutex_unlock (&self->lock); break; } default: G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); break; } } static GstPad * gst_concat_request_new_pad (GstElement * element, GstPadTemplate * templ, const gchar * name, const GstCaps * caps) { GstConcat *self = GST_CONCAT (element); GstPad *sinkpad; gchar *pad_name; gboolean do_notify = FALSE; GST_DEBUG_OBJECT (element, "requesting pad"); g_mutex_lock (&self->lock); pad_name = g_strdup_printf ("sink_%u", self->pad_count); self->pad_count++; g_mutex_unlock (&self->lock); sinkpad = GST_PAD_CAST (g_object_new (GST_TYPE_CONCAT_PAD, "name", pad_name, "direction", templ->direction, "template", templ, NULL)); g_free (pad_name); gst_pad_set_chain_function (sinkpad, GST_DEBUG_FUNCPTR (gst_concat_sink_chain)); gst_pad_set_event_function (sinkpad, GST_DEBUG_FUNCPTR (gst_concat_sink_event)); gst_pad_set_query_function (sinkpad, GST_DEBUG_FUNCPTR (gst_concat_sink_query)); GST_OBJECT_FLAG_SET (sinkpad, GST_PAD_FLAG_PROXY_CAPS); GST_OBJECT_FLAG_SET (sinkpad, GST_PAD_FLAG_PROXY_ALLOCATION); gst_pad_set_active (sinkpad, TRUE); g_mutex_lock (&self->lock); self->sinkpads = g_list_prepend (self->sinkpads, gst_object_ref (sinkpad)); if (!self->current_sinkpad) { do_notify = TRUE; self->current_sinkpad = gst_object_ref (sinkpad); } g_mutex_unlock (&self->lock); gst_element_add_pad (element, sinkpad); if (do_notify) gst_concat_notify_active_pad (self); return sinkpad; } static void gst_concat_release_pad (GstElement * element, GstPad * pad) { GstConcat *self = GST_CONCAT (element); GstConcatPad *spad = GST_CONCAT_PAD_CAST (pad); GList *l; gboolean current_pad_removed = FALSE; gboolean eos = FALSE; gboolean do_notify = FALSE; GST_DEBUG_OBJECT (self, "releasing pad"); g_mutex_lock (&self->lock); spad->flushing = TRUE; g_cond_broadcast (&self->cond); g_mutex_unlock (&self->lock); gst_pad_set_active (pad, FALSE); /* Now the pad is definitely not running anymore */ g_mutex_lock (&self->lock); if (self->current_sinkpad == GST_PAD_CAST (spad)) { eos = !gst_concat_switch_pad (self); current_pad_removed = TRUE; do_notify = TRUE; } for (l = self->sinkpads; l; l = l->next) { if ((gpointer) spad == l->data) { gst_object_unref (spad); self->sinkpads = g_list_delete_link (self->sinkpads, l); break; } } g_mutex_unlock (&self->lock); gst_element_remove_pad (GST_ELEMENT_CAST (self), pad); if (do_notify) gst_concat_notify_active_pad (self); if (GST_STATE (self) > GST_STATE_READY) { if (current_pad_removed && !eos) gst_element_post_message (GST_ELEMENT_CAST (self), gst_message_new_duration_changed (GST_OBJECT_CAST (self))); /* FIXME: Sending EOS from application thread */ if (eos) gst_pad_push_event (self->srcpad, gst_event_new_eos ()); } } /* Returns FALSE if flushing * Must be called from the pad's streaming thread */ static gboolean gst_concat_pad_wait (GstConcatPad * spad, GstConcat * self) { g_mutex_lock (&self->lock); if (spad->flushing) { g_mutex_unlock (&self->lock); GST_DEBUG_OBJECT (spad, "Flushing"); return FALSE; } while (spad != GST_CONCAT_PAD_CAST (self->current_sinkpad)) { GST_TRACE_OBJECT (spad, "Not the current sinkpad - waiting"); g_cond_wait (&self->cond, &self->lock); if (spad->flushing) { g_mutex_unlock (&self->lock); GST_DEBUG_OBJECT (spad, "Flushing"); return FALSE; } } /* This pad can only become not the current sinkpad from * a) This streaming thread (we hold the stream lock) * b) Releasing the pad (takes the stream lock, see above) * * Unlocking here is thus safe and we can safely push * serialized data to our srcpad */ GST_DEBUG_OBJECT (spad, "Now the current sinkpad"); g_mutex_unlock (&self->lock); return TRUE; } static GstFlowReturn gst_concat_sink_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer) { GstFlowReturn ret; GstConcat *self = GST_CONCAT (parent); GstConcatPad *spad = GST_CONCAT_PAD (pad); GST_LOG_OBJECT (pad, "received buffer %p", buffer); if (!gst_concat_pad_wait (spad, self)) return GST_FLOW_FLUSHING; if (self->last_stop == GST_CLOCK_TIME_NONE) self->last_stop = spad->segment.start; if (self->format == GST_FORMAT_TIME) { GstClockTime start_time = GST_BUFFER_TIMESTAMP (buffer); GstClockTime end_time = GST_CLOCK_TIME_NONE; if (start_time != GST_CLOCK_TIME_NONE) end_time = start_time; if (GST_BUFFER_DURATION_IS_VALID (buffer)) end_time += GST_BUFFER_DURATION (buffer); if (end_time != GST_CLOCK_TIME_NONE && end_time > self->last_stop) self->last_stop = end_time; } else { self->last_stop += gst_buffer_get_size (buffer); } ret = gst_pad_push (self->srcpad, buffer); GST_LOG_OBJECT (pad, "handled buffer %s", gst_flow_get_name (ret)); return ret; } /* Returns FALSE if no further pad, must be called with concat lock */ static gboolean gst_concat_switch_pad (GstConcat * self) { GList *l; gboolean next; GstSegment segment; gint64 last_stop; segment = GST_CONCAT_PAD (self->current_sinkpad)->segment; last_stop = self->last_stop; if (last_stop == GST_CLOCK_TIME_NONE) last_stop = segment.stop; if (last_stop == GST_CLOCK_TIME_NONE) last_stop = segment.start; g_assert (last_stop != GST_CLOCK_TIME_NONE); if (last_stop > segment.stop) last_stop = segment.stop; if (segment.format == GST_FORMAT_TIME) last_stop = gst_segment_to_running_time (&segment, segment.format, last_stop); else last_stop += segment.start; self->current_start_offset += last_stop; for (l = self->sinkpads; l; l = l->next) { if ((gpointer) self->current_sinkpad == l->data) { l = l->prev; GST_DEBUG_OBJECT (self, "Switching from pad %" GST_PTR_FORMAT " to %" GST_PTR_FORMAT, self->current_sinkpad, l ? l->data : NULL); gst_object_unref (self->current_sinkpad); self->current_sinkpad = l ? gst_object_ref (l->data) : NULL; g_cond_broadcast (&self->cond); break; } } next = self->current_sinkpad != NULL; self->last_stop = GST_CLOCK_TIME_NONE; return next; } static void gst_concat_notify_active_pad (GstConcat * self) { g_object_notify_by_pspec ((GObject *) self, pspec_active_pad); } static gboolean gst_concat_sink_event (GstPad * pad, GstObject * parent, GstEvent * event) { GstConcat *self = GST_CONCAT (parent); GstConcatPad *spad = GST_CONCAT_PAD_CAST (pad); gboolean ret = TRUE; GST_LOG_OBJECT (pad, "received event %" GST_PTR_FORMAT, event); switch (GST_EVENT_TYPE (event)) { case GST_EVENT_STREAM_START:{ if (!gst_concat_pad_wait (spad, self)) { ret = FALSE; gst_event_unref (event); } else { ret = gst_pad_event_default (pad, parent, event); } break; } case GST_EVENT_SEGMENT:{ gboolean adjust_base; /* Drop segment event, we create our own one */ gst_event_copy_segment (event, &spad->segment); gst_event_unref (event); g_mutex_lock (&self->lock); adjust_base = self->adjust_base; if (self->format == GST_FORMAT_UNDEFINED) { if (spad->segment.format != GST_FORMAT_TIME && spad->segment.format != GST_FORMAT_BYTES) { g_mutex_unlock (&self->lock); GST_ELEMENT_ERROR (self, CORE, FAILED, (NULL), ("Can only operate in TIME or BYTES format")); ret = FALSE; break; } self->format = spad->segment.format; GST_DEBUG_OBJECT (self, "Operating in %s format", gst_format_get_name (self->format)); g_mutex_unlock (&self->lock); } else if (self->format != spad->segment.format) { g_mutex_unlock (&self->lock); GST_ELEMENT_ERROR (self, CORE, FAILED, (NULL), ("Operating in %s format but new pad has %s", gst_format_get_name (self->format), gst_format_get_name (spad->segment.format))); ret = FALSE; } else { g_mutex_unlock (&self->lock); } if (!gst_concat_pad_wait (spad, self)) { ret = FALSE; } else { GstSegment segment = spad->segment; if (adjust_base) { /* We know no duration */ segment.duration = -1; /* Update segment values to be continous with last stream */ if (self->format == GST_FORMAT_TIME) { segment.base += self->current_start_offset; } else { /* Shift start/stop byte position */ segment.start += self->current_start_offset; if (segment.stop != -1) segment.stop += self->current_start_offset; } } gst_pad_push_event (self->srcpad, gst_event_new_segment (&segment)); } break; } case GST_EVENT_EOS:{ gst_event_unref (event); if (!gst_concat_pad_wait (spad, self)) { ret = FALSE; } else { gboolean next; g_mutex_lock (&self->lock); next = gst_concat_switch_pad (self); g_mutex_unlock (&self->lock); ret = TRUE; gst_concat_notify_active_pad (self); if (!next) { gst_pad_push_event (self->srcpad, gst_event_new_eos ()); } else { gst_element_post_message (GST_ELEMENT_CAST (self), gst_message_new_duration_changed (GST_OBJECT_CAST (self))); } } break; } case GST_EVENT_FLUSH_START:{ gboolean forward; g_mutex_lock (&self->lock); spad->flushing = TRUE; g_cond_broadcast (&self->cond); forward = (self->current_sinkpad == GST_PAD_CAST (spad)); g_mutex_unlock (&self->lock); if (forward) ret = gst_pad_event_default (pad, parent, event); else gst_event_unref (event); break; } case GST_EVENT_FLUSH_STOP:{ gboolean forward; gst_segment_init (&spad->segment, GST_FORMAT_UNDEFINED); spad->flushing = FALSE; g_mutex_lock (&self->lock); forward = (self->current_sinkpad == GST_PAD_CAST (spad)); g_mutex_unlock (&self->lock); if (forward) { gboolean reset_time; gst_event_parse_flush_stop (event, &reset_time); if (reset_time) { GST_DEBUG_OBJECT (self, "resetting start offset to 0 after flushing with reset_time = TRUE"); self->current_start_offset = 0; } ret = gst_pad_event_default (pad, parent, event); } else { gst_event_unref (event); } break; } default:{ /* Wait for other serialized events before forwarding */ if (GST_EVENT_IS_SERIALIZED (event) && !gst_concat_pad_wait (spad, self)) { gst_event_unref (event); ret = FALSE; } else { ret = gst_pad_event_default (pad, parent, event); } break; } } return ret; } static gboolean gst_concat_sink_query (GstPad * pad, GstObject * parent, GstQuery * query) { GstConcat *self = GST_CONCAT (parent); GstConcatPad *spad = GST_CONCAT_PAD_CAST (pad); gboolean ret = TRUE; GST_LOG_OBJECT (pad, "received query %" GST_PTR_FORMAT, query); switch (GST_QUERY_TYPE (query)) { default: /* Wait for other serialized queries before forwarding */ if (GST_QUERY_IS_SERIALIZED (query) && !gst_concat_pad_wait (spad, self)) { ret = FALSE; } else { ret = gst_pad_query_default (pad, parent, query); } break; } return ret; } static gboolean gst_concat_src_event (GstPad * pad, GstObject * parent, GstEvent * event) { GstConcat *self = GST_CONCAT (parent); gboolean ret = TRUE; GST_LOG_OBJECT (pad, "received event %" GST_PTR_FORMAT, event); switch (GST_EVENT_TYPE (event)) { case GST_EVENT_SEEK:{ GstPad *sinkpad = NULL; g_mutex_lock (&self->lock); if ((sinkpad = self->current_sinkpad)) gst_object_ref (sinkpad); g_mutex_unlock (&self->lock); if (sinkpad) { ret = gst_pad_push_event (sinkpad, event); gst_object_unref (sinkpad); } else { gst_event_unref (event); ret = FALSE; } break; } case GST_EVENT_QOS:{ GstQOSType type; GstClockTimeDiff diff; GstClockTime timestamp; gdouble proportion; gst_event_parse_qos (event, &type, &proportion, &diff, ×tamp); gst_event_unref (event); if (timestamp != GST_CLOCK_TIME_NONE && timestamp > self->current_start_offset) { timestamp -= self->current_start_offset; event = gst_event_new_qos (type, proportion, diff, timestamp); ret = gst_pad_push_event (self->current_sinkpad, event); } else { ret = FALSE; } break; } case GST_EVENT_FLUSH_STOP:{ gboolean reset_time; gst_event_parse_flush_stop (event, &reset_time); if (reset_time) { GST_DEBUG_OBJECT (self, "resetting start offset to 0 after flushing with reset_time = TRUE"); self->current_start_offset = 0; } ret = gst_pad_event_default (pad, parent, event); break; } default: ret = gst_pad_event_default (pad, parent, event); break; } return ret; } static gboolean gst_concat_src_query (GstPad * pad, GstObject * parent, GstQuery * query) { gboolean ret = TRUE; GST_LOG_OBJECT (pad, "received query %" GST_PTR_FORMAT, query); switch (GST_QUERY_TYPE (query)) { default: ret = gst_pad_query_default (pad, parent, query); break; } return ret; } static void reset_pad (const GValue * data, gpointer user_data) { GstPad *pad = g_value_get_object (data); GstConcatPad *spad = GST_CONCAT_PAD_CAST (pad); gst_segment_init (&spad->segment, GST_FORMAT_UNDEFINED); spad->flushing = FALSE; } static void unblock_pad (const GValue * data, gpointer user_data) { GstPad *pad = g_value_get_object (data); GstConcatPad *spad = GST_CONCAT_PAD_CAST (pad); spad->flushing = TRUE; } static GstStateChangeReturn gst_concat_change_state (GstElement * element, GstStateChange transition) { GstConcat *self = GST_CONCAT (element); GstStateChangeReturn ret; switch (transition) { case GST_STATE_CHANGE_READY_TO_PAUSED:{ self->format = GST_FORMAT_UNDEFINED; self->current_start_offset = 0; self->last_stop = GST_CLOCK_TIME_NONE; break; } case GST_STATE_CHANGE_PAUSED_TO_READY:{ GstIterator *iter = gst_element_iterate_sink_pads (element); GstIteratorResult res; g_mutex_lock (&self->lock); do { res = gst_iterator_foreach (iter, unblock_pad, NULL); } while (res == GST_ITERATOR_RESYNC); gst_iterator_free (iter); g_cond_broadcast (&self->cond); g_mutex_unlock (&self->lock); if (res == GST_ITERATOR_ERROR) return GST_STATE_CHANGE_FAILURE; break; } default: break; } ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition); if (ret == GST_STATE_CHANGE_FAILURE) return ret; switch (transition) { case GST_STATE_CHANGE_PAUSED_TO_READY:{ GstIterator *iter = gst_element_iterate_sink_pads (element); GstIteratorResult res; do { res = gst_iterator_foreach (iter, reset_pad, NULL); } while (res == GST_ITERATOR_RESYNC); gst_iterator_free (iter); if (res == GST_ITERATOR_ERROR) return GST_STATE_CHANGE_FAILURE; break; } default: break; } return ret; }