diff --git a/ext/a52dec/gsta52dec.c b/ext/a52dec/gsta52dec.c
index c25397bf69..aafa2aa773 100644
--- a/ext/a52dec/gsta52dec.c
+++ b/ext/a52dec/gsta52dec.c
@@ -217,6 +217,8 @@ gst_a52dec_class_init (GstA52DecClass * klass)
 #endif
 
   GST_LOG ("CPU flags: a52=%08x, orc=%08x", klass->a52_cpuflags, cpuflags);
+
+  gst_type_mark_as_plugin_api (GST_TYPE_A52DEC_MODE);
 }
 
 static void
diff --git a/ext/amrnb/amrnbdec.c b/ext/amrnb/amrnbdec.c
index 906cb26efb..6c94112cfa 100644
--- a/ext/amrnb/amrnbdec.c
+++ b/ext/amrnb/amrnbdec.c
@@ -136,6 +136,8 @@ gst_amrnbdec_class_init (GstAmrnbDecClass * klass)
 
   GST_DEBUG_CATEGORY_INIT (gst_amrnbdec_debug, "amrnbdec", 0,
       "AMR-NB audio decoder");
+
+  gst_type_mark_as_plugin_api (GST_AMRNB_VARIANT_TYPE);
 }
 
 static void
diff --git a/ext/amrnb/amrnbenc.c b/ext/amrnb/amrnbenc.c
index 06c2a86216..60aac208c8 100644
--- a/ext/amrnb/amrnbenc.c
+++ b/ext/amrnb/amrnbenc.c
@@ -164,6 +164,8 @@ gst_amrnbenc_class_init (GstAmrnbEncClass * klass)
 
   GST_DEBUG_CATEGORY_INIT (gst_amrnbenc_debug, "amrnbenc", 0,
       "AMR-NB audio encoder");
+
+  gst_type_mark_as_plugin_api (GST_AMRNBENC_BANDMODE_TYPE);
 }
 
 static void
diff --git a/ext/sidplay/gstsiddec.cc b/ext/sidplay/gstsiddec.cc
index feb8ab78cf..487b059d74 100644
--- a/ext/sidplay/gstsiddec.cc
+++ b/ext/sidplay/gstsiddec.cc
@@ -202,6 +202,9 @@ gst_siddec_class_init (GstSidDecClass * klass)
 
   GST_DEBUG_CATEGORY_INIT (gst_siddec_debug, "siddec", 0,
       "C64 sid song player");
+
+  gst_type_mark_as_plugin_api (GST_TYPE_SID_CLOCK);
+  gst_type_mark_as_plugin_api (GST_TYPE_SID_MEMORY);
 }
 
 static void
diff --git a/ext/x264/gstx264enc.c b/ext/x264/gstx264enc.c
index 961840ebc5..1c4949366e 100644
--- a/ext/x264/gstx264enc.c
+++ b/ext/x264/gstx264enc.c
@@ -1204,6 +1204,14 @@ gst_x264_enc_class_init (GstX264EncClass * klass)
 
   gst_element_class_add_pad_template (element_class, sink_templ);
   gst_element_class_add_static_pad_template (element_class, &src_factory);
+
+  gst_type_mark_as_plugin_api (GST_X264_ENC_ANALYSE_TYPE);
+  gst_type_mark_as_plugin_api (GST_X264_ENC_FRAME_PACKING_TYPE);
+  gst_type_mark_as_plugin_api (GST_X264_ENC_ME_TYPE);
+  gst_type_mark_as_plugin_api (GST_X264_ENC_PASS_TYPE);
+  gst_type_mark_as_plugin_api (GST_X264_ENC_PSY_TUNE_TYPE);
+  gst_type_mark_as_plugin_api (GST_X264_ENC_SPEED_PRESET_TYPE);
+  gst_type_mark_as_plugin_api (GST_X264_ENC_TUNE_TYPE);
 }
 
 static void