Add frame stepping in PAUSED example

configure.ac

@@ -654,6 +654,7 @@ tests/misc/Makefile
 tests/examples/Makefile
 tests/examples/adapter/Makefile
 tests/examples/controller/Makefile
+tests/examples/stepping/Makefile
 tests/examples/helloworld/Makefile
 tests/examples/launch/Makefile
 tests/examples/manual/Makefile

tests/examples/Makefile.am

@@ -23,7 +23,8 @@ always_dirs = \
 	manual     \
 	metadata   \
 	streams    \
-	queue
+	queue      \
+	stepping
 
 #appreader
 #cutter

tests/examples/stepping/.gitignore

@@ -0,0 +1,5 @@
+framestep1
+*.bb
+*.bbg
+*.da
+framestep1-framestep1.gcno

tests/examples/stepping/Makefile.am

@@ -0,0 +1,4 @@
+noinst_PROGRAMS = framestep1
+
+framestep1_LDADD = $(GST_OBJ_LIBS)
+framestep1_CFLAGS = $(GST_OBJ_CFLAGS)

tests/examples/stepping/framestep1.c

@@ -0,0 +1,110 @@
+#include <stdlib.h>
+#include <gst/gst.h>
+
+static void
+event_loop (GstElement * pipe)
+{
+  GstBus *bus;
+  GstMessage *message = NULL;
+
+  bus = gst_element_get_bus (GST_ELEMENT (pipe));
+
+  while (TRUE) {
+    message = gst_bus_timed_pop_filtered (bus, GST_MESSAGE_ANY, -1);
+
+    g_assert (message != NULL);
+
+    switch (message->type) {
+      case GST_MESSAGE_EOS:
+        g_message ("got EOS");
+        gst_message_unref (message);
+        return;
+      case GST_MESSAGE_WARNING:
+      case GST_MESSAGE_ERROR:{
+        GError *gerror;
+        gchar *debug;
+
+        gst_message_parse_error (message, &gerror, &debug);
+        gst_object_default_error (GST_MESSAGE_SRC (message), gerror, debug);
+        gst_message_unref (message);
+        g_error_free (gerror);
+        g_free (debug);
+        return;
+      }
+      default:
+        gst_message_unref (message);
+        break;
+    }
+  }
+}
+
+/* signalled when a new preroll buffer is available */
+static void
+new_preroll (GstElement * appsink, gpointer user_data)
+{
+  GstBuffer *buffer;
+
+  g_signal_emit_by_name (appsink, "pull-preroll", &buffer);
+
+  g_message ("have new-preroll buffer %p, timestamp %" GST_TIME_FORMAT, buffer,
+      GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buffer)));
+
+  gst_buffer_unref (buffer);
+}
+
+int
+main (int argc, char *argv[])
+{
+  GstElement *bin, *videotestsrc, *appsink;
+
+  gst_init (&argc, &argv);
+
+  /* create a new bin to hold the elements */
+  bin = gst_pipeline_new ("pipeline");
+  g_assert (bin);
+
+  /* create a fake source */
+  videotestsrc = gst_element_factory_make ("videotestsrc", "videotestsrc");
+  g_assert (videotestsrc);
+  g_object_set (videotestsrc, "num-buffers", 10, NULL);
+
+  /* and a fake sink */
+  appsink = gst_element_factory_make ("appsink", "appsink");
+  g_assert (appsink);
+  g_object_set (appsink, "emit-signals", TRUE, NULL);
+  g_object_set (appsink, "sync", FALSE, NULL);
+  g_signal_connect (appsink, "new-preroll", (GCallback) new_preroll, NULL);
+
+  /* add objects to the main pipeline */
+  gst_bin_add (GST_BIN (bin), videotestsrc);
+  gst_bin_add (GST_BIN (bin), appsink);
+
+  /* link the elements */
+  gst_element_link_many (videotestsrc, appsink, NULL);
+
+  /* go to the PAUSED state and wait for preroll */
+  g_message ("prerolling first frame");
+  gst_element_set_state (bin, GST_STATE_PAUSED);
+  gst_element_get_state (bin, NULL, NULL, -1);
+
+  /* step two frames, flush so that new preroll is queued */
+  g_message ("stepping two frames");
+  g_assert (gst_element_send_event (bin,
+          gst_event_new_step (GST_FORMAT_BUFFERS, 2, 1.0, TRUE, FALSE)));
+
+  /* wait for step to complete */
+  gst_element_get_state (bin, NULL, NULL, -1);
+
+  g_message ("stepped two frames");
+
+  g_message ("playing until EOS");
+  gst_element_set_state (bin, GST_STATE_PLAYING);
+  /* Run event loop listening for bus messages until EOS or ERROR */
+  event_loop (bin);
+  g_message ("finished");
+
+  /* stop the bin */
+  gst_element_set_state (bin, GST_STATE_NULL);
+
+  exit (0);
+}