-for each category. Level is in the range 0-5 where 0 will show no messages, and
-5 will show all messages. The wildcard * can be used to match category names.
+for each category. Level is in the range 0-9 where 0 will show no messages, and
+9 will show all messages. The wildcard * can be used to match category names.
+Note that the order of categories and levels is important, wildcards at the
+end may override levels set earlier. The log levels are: 1=ERROR, 2=WARNING,
+3=FIXME, 4=INFO, 5=DEBUG, 6=LOG, 7=TRACE, 9=MEMDUMP. Since GStreamer 1.2 one
+can also use the debug level names, e.g. \-\-gst\-debug=*sink:LOG. A full
+description of the various debug levels can be found in the GStreamer core
+library API documentation, in the "Running GStreamer Applications" section.