media: start live streams in blocked state

Start live streams in the blocked state and make them preroll using the
messages. This ensure that no data is played by the sink until we explicitly
unblock the stream right before going to PLAYING.

See https://bugzilla.gnome.org/show_bug.cgi?id=711257

diff --git a/gst/rtsp-server/rtsp-media.c b/gst/rtsp-server/rtsp-media.c
index b3cff1d..e1dd573 100644 (file)
--- a/gst/rtsp-server/rtsp-media.c
+++ b/gst/rtsp-server/rtsp-media.c
@@ -86,6 +86,7 @@ struct _GstRTSPMediaPrivate
   gboolean eos_shutdown;
   guint buffer_size;
   GstRTSPAddressPool *pool;
+  gboolean blocked;
 
   GstElement *element;
   GRecMutex state_lock;         /* locking order: state lock, lock */
@@ -1265,6 +1266,22 @@ conversion_failed:
   }
 }
 
+static void
+stream_update_blocked (GstRTSPStream * stream, GstRTSPMedia * media)
+{
+  gst_rtsp_stream_set_blocked (stream, media->priv->blocked);
+}
+
+static void
+media_streams_set_blocked (GstRTSPMedia * media, gboolean blocked)
+{
+  GstRTSPMediaPrivate *priv = media->priv;
+
+  GST_DEBUG ("media %p set blocked %d", media, blocked);
+  priv->blocked = blocked;
+  g_ptr_array_foreach (priv->streams, (GFunc) stream_update_blocked, media);
+}
+
 /**
  * gst_rtsp_media_seek:
  * @media: a #GstRTSPMedia
@@ -1342,6 +1359,10 @@ gst_rtsp_media_seek (GstRTSPMedia * media, GstRTSPTimeRange * range)
     GST_INFO ("seeking to %" GST_TIME_FORMAT " - %" GST_TIME_FORMAT,
         GST_TIME_ARGS (start), GST_TIME_ARGS (stop));
 
+    priv->status = GST_RTSP_MEDIA_STATUS_PREPARING;
+    if (priv->blocked)
+      media_streams_set_blocked (media, TRUE);
+
     res = gst_element_seek (priv->pipeline, 1.0, GST_FORMAT_TIME,
         flags, start_type, start, stop_type, stop);
 
@@ -1435,6 +1456,23 @@ gst_rtsp_media_get_status (GstRTSPMedia * media)
   return result;
 }
 
+static void
+stream_collect_blocking (GstRTSPStream * stream, gboolean * blocked)
+{
+  *blocked &= gst_rtsp_stream_is_blocking (stream);
+}
+
+static gboolean
+media_streams_blocking (GstRTSPMedia * media)
+{
+  gboolean blocking = TRUE;
+
+  g_ptr_array_foreach (media->priv->streams, (GFunc) stream_collect_blocking,
+      &blocking);
+
+  return blocking;
+}
+
 /* called with state-lock */
 static gboolean
 default_handle_message (GstRTSPMedia * media, GstMessage * message)
@@ -1512,7 +1550,22 @@ default_handle_message (GstRTSPMedia * media, GstMessage * message)
       break;
     }
     case GST_MESSAGE_ELEMENT:
+    {
+      const GstStructure *s;
+
+      s = gst_message_get_structure (message);
+      if (gst_structure_has_name (s, "GstRTSPStreamBlocking")) {
+        GST_DEBUG ("media received blocking message");
+        if (priv->blocked && media_streams_blocking (media)) {
+          GST_DEBUG ("media is blocking");
+          collect_media_stats (media);
+
+          if (priv->status == GST_RTSP_MEDIA_STATUS_PREPARING)
+            gst_rtsp_media_set_status (media, GST_RTSP_MEDIA_STATUS_PREPARED);
+        }
+      }
       break;
+    }
     case GST_MESSAGE_STREAM_STATUS:
       break;
     case GST_MESSAGE_ASYNC_DONE:
@@ -1721,6 +1774,8 @@ start_preroll (GstRTSPMedia * media)
        * seeking query in preroll instead */
       priv->seekable = FALSE;
       priv->is_live = TRUE;
+      /* start blocked  to make sure nothing goes to the sink */
+      media_streams_set_blocked (media, TRUE);
       ret = gst_element_set_state (priv->pipeline, GST_STATE_PLAYING);
       if (ret == GST_STATE_CHANGE_FAILURE)
         goto state_failed;
@@ -2231,6 +2286,10 @@ media_set_pipeline_state_locked (GstRTSPMedia * media, GstState state)
     if (priv->buffering) {
       GST_INFO ("Buffering busy, delay state change");
     } else {
+      if (state == GST_STATE_PLAYING)
+        /* make sure pads are not blocking anymore when going to PLAYING */
+        media_streams_set_blocked (media, FALSE);
+
       gst_element_set_state (priv->pipeline, state);
     }
   }