diff --git a/gst/playback/gstplaysinkconvertbin.c b/gst/playback/gstplaysinkconvertbin.c
index 1daa7f1fca..bade4ab9a7 100644
--- a/gst/playback/gstplaysinkconvertbin.c
+++ b/gst/playback/gstplaysinkconvertbin.c
@@ -378,6 +378,7 @@ gst_play_sink_convert_bin_getcaps (GstPad * pad)
       GstCaps *peer_caps = gst_pad_get_caps_reffed (peer);
       gst_object_unref (peer);
       if (self->converter_caps) {
+        peer_caps = gst_caps_make_writable (peer_caps);
         gst_caps_merge (peer_caps, gst_caps_ref (self->converter_caps));
         ret = peer_caps;
       } else {