diff --git a/ChangeLog b/ChangeLog
index 35ada34f23..ef4b502616 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2004-02-13  David Schleef  <ds@schleef.org>
+
+	* gst/silence/gstsilence.c: (gst_silence_class_init),
+	(gst_silence_set_clock), (gst_silence_get),
+	(gst_silence_set_property), (gst_silence_get_property):
+	* gst/silence/gstsilence.h: Add sync property.
+	* gst/sine/gstsinesrc.c: (gst_sinesrc_class_init),
+	(gst_sinesrc_init), (gst_sinesrc_set_clock), (gst_sinesrc_get),
+	(gst_sinesrc_set_property), (gst_sinesrc_get_property):
+	* gst/sine/gstsinesrc.h: Add sync property.
+
 2004-02-13  David Schleef  <ds@schleef.org>
 
 	* gst/intfloat/gstint2float.c: (conv_f32_s16),
diff --git a/gst/sine/gstsinesrc.c b/gst/sine/gstsinesrc.c
index 8e62788bde..5389fe7ca3 100644
--- a/gst/sine/gstsinesrc.c
+++ b/gst/sine/gstsinesrc.c
@@ -52,6 +52,7 @@ enum {
   ARG_SAMPLES_PER_BUFFER,
   ARG_FREQ,
   ARG_VOLUME,
+  ARG_SYNC
 };
 
 static GstStaticPadTemplate gst_sinesrc_src_template =
@@ -86,6 +87,7 @@ static GstPadLinkReturn
 						     const GstCaps *caps);
 static GstElementStateReturn
                     gst_sinesrc_change_state        (GstElement *element);
+static void gst_sinesrc_set_clock (GstElement *element, GstClock *clock);
 
 static void 	    gst_sinesrc_update_freq         (const GValue *value, 
 		                                     gpointer data);
@@ -159,12 +161,16 @@ gst_sinesrc_class_init (GstSineSrcClass *klass)
   g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_VOLUME,
     g_param_spec_double ("volume", "Volume", "Volume",
                         0.0, 1.0, 0.8, G_PARAM_READWRITE)); 
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_SYNC,
+      g_param_spec_boolean ("sync", "Sync", "Synchronize to clock",
+        TRUE, G_PARAM_READWRITE));
                                      
   gobject_class->set_property = gst_sinesrc_set_property;
   gobject_class->get_property = gst_sinesrc_get_property;
   gobject_class->dispose = gst_sinesrc_dispose;
 
   gstelement_class->change_state = gst_sinesrc_change_state;
+  gstelement_class->set_clock = gst_sinesrc_set_clock;
 }
 
 static void 
@@ -182,6 +188,7 @@ gst_sinesrc_init (GstSineSrc *src)
   src->samplerate = 44100;
   src->volume = 1.0;
   src->freq = 440.0;
+  src->sync = TRUE;
   
   src->table_pos = 0.0;
   src->table_size = 1024;
@@ -228,6 +235,14 @@ gst_sinesrc_dispose (GObject *object)
   GST_CALL_PARENT (G_OBJECT_CLASS, dispose, (object));
 }
 
+static void
+gst_sinesrc_set_clock (GstElement *element, GstClock *clock)
+{
+  GstSineSrc *sinesrc = GST_SINESRC (element);
+
+  gst_object_replace ((GstObject **)&sinesrc->clock, (GstObject *)clock);
+}
+
 static GstCaps *
 gst_sinesrc_src_fixate (GstPad *pad, const GstCaps *caps)
 {
@@ -345,6 +360,11 @@ gst_sinesrc_get (GstPad *pad)
   buf = gst_buffer_new_and_alloc (src->samples_per_buffer * 2);
 
   GST_BUFFER_TIMESTAMP(buf) = src->timestamp;
+  if (src->sync) {
+    if (src->clock) {
+      gst_element_wait (GST_ELEMENT(src), GST_BUFFER_TIMESTAMP (buf));
+    }
+  }
   GST_BUFFER_OFFSET (buf) = src->offset;
   GST_BUFFER_DURATION (buf) = tdiff;
 
@@ -430,6 +450,9 @@ gst_sinesrc_set_property (GObject *object, guint prop_id,
       gst_dpman_bypass_dparam (src->dpman, "volume");
       src->volume = g_value_get_double (value);
       break;
+    case ARG_SYNC:
+      src->sync = g_value_get_boolean (value);
+      break;
     default:
       break;
   }
@@ -458,6 +481,9 @@ gst_sinesrc_get_property (GObject *object, guint prop_id,
     case ARG_VOLUME:
       g_value_set_double (value, src->volume);
       break;      
+    case ARG_SYNC:
+      g_value_set_boolean (value, src->sync);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
diff --git a/gst/sine/gstsinesrc.h b/gst/sine/gstsinesrc.h
index fbfc455e9b..a98d8301fb 100644
--- a/gst/sine/gstsinesrc.h
+++ b/gst/sine/gstsinesrc.h
@@ -57,6 +57,7 @@ struct _GstSineSrc {
   /* parameters */
   gdouble volume;
   gdouble freq;
+  gboolean sync;
   
   /* lookup table data */
   gdouble *table_data;
@@ -79,6 +80,8 @@ struct _GstSineSrc {
   gdouble accumulator;
 
   gboolean tags_pushed;
+
+  GstClock *clock;
 };
 
 struct _GstSineSrcClass {