diff --git a/libs/gst/base/gstcollectpads.h b/libs/gst/base/gstcollectpads.h
index 79b7fa4fee..c33ca4f5a1 100644
--- a/libs/gst/base/gstcollectpads.h
+++ b/libs/gst/base/gstcollectpads.h
@@ -147,7 +147,7 @@ typedef GstFlowReturn (*GstCollectPadsFunction) (GstCollectPads *pads, gpointer
  * GstCollectPadsBufferFunction:
  * @pads: the #GstCollectPads that trigered the callback
  * @data: the #GstCollectData of pad that has received the buffer
- * @buffer: the #GstBuffer
+ * @buffer: (transfer full): the #GstBuffer
  * @user_data: user data passed to gst_collect_pads_set_buffer_function()
  *
  * A function that will be called when a (considered oldest) buffer can be muxed.