Document first high-level demo.

tests/examples/test1.c

@@ -19,7 +19,7 @@
 
 #include <ges/ges.h>
 
-/* A simple timeline with 3 video-only sources */
+/* A simple timeline with 3 audio/video sources */
 
 static gboolean
 fill_customsrc (GESTimelineObject * object, GESTrackObject * trobject,
@@ -28,6 +28,9 @@ fill_customsrc (GESTimelineObject * object, GESTrackObject * trobject,
   GstElement *src;
   guint var = GPOINTER_TO_UINT (user_data);
 
+  /* Based on the Track type, we will either put a videotestsrc
+   * or an audiotestsrc */
+
   if (trobject->track->type == GES_TRACK_TYPE_VIDEO) {
     src = gst_element_factory_make ("videotestsrc", NULL);
     g_object_set (src, "pattern", var, NULL);
@@ -37,6 +40,7 @@ fill_customsrc (GESTimelineObject * object, GESTrackObject * trobject,
   } else
     return FALSE;
 
+  /* Finally we fill in the gnlobject */
   return gst_bin_add (GST_BIN (gnlobj), src);
 }
 
@@ -50,24 +54,47 @@ main (int argc, gchar ** argv)
   GESCustomTimelineSource *src1, *src2, *src3;
   GMainLoop *mainloop;
 
+  /* Initialize GStreamer (this will parse environment variables and commandline
+   * arguments. */
   gst_init (&argc, &argv);
 
+  /* Initialize the GStreamer Editing Services */
   ges_init ();
 
-  pipeline = ges_timeline_pipeline_new ();
+  /* Setup of a A/V timeline */
+
+  /* This is our main GESTimeline */
   timeline = ges_timeline_new ();
+
+  /* We want to output both audio and video, therefore we
+   * grab two tracks, one for each output type. */
   trackv = ges_track_video_raw_new ();
   tracka = ges_track_audio_raw_new ();
+
+  /* We are only going to be doing one layer of timeline objects */
   layer = ges_timeline_layer_new ();
 
+  /* Add the tracks and the layer to the timeline */
   if (!ges_timeline_add_layer (timeline, layer))
     return -1;
-
   if (!ges_timeline_add_track (timeline, trackv))
     return -1;
   if (!ges_timeline_add_track (timeline, tracka))
     return -1;
 
+  /* Here we've finished initializing our timeline, we're 
+   * ready to start using it... by solely working with the layer !*/
+
+
+
+  /* We are here creating 3 sources of 1s each which we will put one after
+   * the other.
+   *
+   * For our sources, and since we want to prototype quickly, we just use
+   * a GESCustomTimelineSource. This will use the callback we provide to
+   * fill in the GESTrackObject.
+   * */
+
   src1 = ges_custom_timeline_source_new (fill_customsrc, GUINT_TO_POINTER (0));
   g_object_set (src1, "start", 0, "duration", GST_SECOND, NULL);
   src2 = ges_custom_timeline_source_new (fill_customsrc, GUINT_TO_POINTER (1));
@@ -75,16 +102,31 @@ main (int argc, gchar ** argv)
   src3 = ges_custom_timeline_source_new (fill_customsrc, GUINT_TO_POINTER (0));
   g_object_set (src3, "start", 2 * GST_SECOND, "duration", GST_SECOND, NULL);
 
+  /* Add those sources to our layer */
   ges_timeline_layer_add_object (layer, (GESTimelineObject *) src1);
   ges_timeline_layer_add_object (layer, (GESTimelineObject *) src2);
   ges_timeline_layer_add_object (layer, (GESTimelineObject *) src3);
 
+
+  /* In order to view our timeline, let's grab a convenience pipeline to put
+   * our timeline in. */
+  pipeline = ges_timeline_pipeline_new ();
+
+  /* Add the timeline to that pipeline */
   if (!ges_timeline_pipeline_add_timeline (pipeline, timeline))
     return -1;
 
+  /* The following is standard usage of a GStreamer pipeline (note how you haven't
+   * had to care about GStreamer so far ?).
+   *
+   * We set the pipeline to playing ... */
   gst_element_set_state (GST_ELEMENT (pipeline), GST_STATE_PLAYING);
 
+  /* .. and we start a GMainLoop. GES **REQUIRES** a GMainLoop to be running in
+   * order to function properly ! */
   mainloop = g_main_loop_new (NULL, FALSE);
+
+  /* Simple code to have the mainloop shutdown after 4s */
   g_timeout_add_seconds (4, (GSourceFunc) g_main_loop_quit, mainloop);
   g_main_loop_run (mainloop);