qtmux: ensure writable buffer metadata before setting caps

diff --git a/gst/quicktime/gstqtmux.c b/gst/quicktime/gstqtmux.c
index 1838c6c..38b1096 100644 (file)
--- a/gst/quicktime/gstqtmux.c
+++ b/gst/quicktime/gstqtmux.c
@@ -819,6 +819,7 @@ gst_qt_mux_send_buffer (GstQTMux * qtmux, GstBuffer * buf, guint64 * offset,
   } else {
     GST_LOG_OBJECT (qtmux, "downstream");
 
+    buf = gst_buffer_make_metadata_writable (buf);
     gst_buffer_set_caps (buf, GST_PAD_CAPS (qtmux->srcpad));
     res = gst_pad_push (qtmux->srcpad, buf);
   }