alex@flash:~/Hacking/Rhythmbox/trunk$ rhythmbox -D match
(11:28:24) [0x80f2028] [rb_debug_init_match] rb-debug.c:141: Debugging enabled
(11:28:28) [0x805f090] [rb_debug_init_match] rb-debug.c:141: Debugging enabled
(11:28:56) [0x80f2028] [encoder_match_mime] rb-encoder-gst.c:675: desired caps are: audio/mpeg, mpegversion=(int)1, layer=(int)3
(11:28:56) [0x80f2028] [encoder_match_mime] rb-encoder-gst.c:679: element caps are: audio/mpeg, mpegversion=(int){ 4, 2 }, channels=(int)[ 1, 6 ], rate=(int)[ 8000, 96000 ]
(11:28:56) [0x80f2028] [encoder_match_mime] rb-encoder-gst.c:683: intersect caps are: EMPTY

(rhythmbox:3803): GStreamer-CRITICAL **: gst_caps_intersect: assertion `GST_IS_CAPS (caps1)' failed

(rhythmbox:3803): GStreamer-CRITICAL **: gst_caps_is_empty: assertion `GST_IS_CAPS (caps)' failed

(rhythmbox:3803): GStreamer-CRITICAL **: gst_caps_is_any: assertion `GST_IS_CAPS (caps)' failed

(rhythmbox:3803): GStreamer-CRITICAL **: gst_caps_is_empty: assertion `GST_IS_CAPS (caps)' failed
(11:28:56) [0x80f2028] [encoder_match_mime] rb-encoder-gst.c:675: desired caps are: 
(11:28:56) [0x80f2028] [encoder_match_mime] rb-encoder-gst.c:679: element caps are: audio/x-flac
(11:28:56) [0x80f2028] [encoder_match_mime] rb-encoder-gst.c:683: intersect caps are: NULL

(rhythmbox:3803): GStreamer-CRITICAL **: gst_caps_unref: assertion `caps != NULL' failed

(rhythmbox:3803): GStreamer-CRITICAL **: gst_caps_unref: assertion `GST_CAPS_REFCOUNT_VALUE (caps) > 0' failed