I imported a few AVCHD videos.  Previewing each individual clip works, but if I drag a clip to the timeline, it doesn't load correctly.  Only one of the thumbnails in the video timeline is drawn, and only a quarter of the audio timeline is drawn.  I can select a clip, but I can't move the playhead; it ignores any clicks I make in the ruler area.  Meanwhile, the following error messages are produced in the terminal:

** Message: pygobject_register_sinkfunc is deprecated (GstObject)
[karen@martin ~]$ pitivi Desktop/walker.xptv 
** Message: pygobject_register_sinkfunc is deprecated (GstObject)
/usr/share/pitivi/python/pitivi/formatters/etree.py:181: FutureWarning: The behavior of this method will change in future versions.  Use specific 'len(elem)' or 'elem is not None' test instead.
  input_streams = element.find("input-streams") or []
/usr/share/pitivi/python/pitivi/formatters/etree.py:363: FutureWarning: The behavior of this method will change in future versions.  Use specific 'len(elem)' or 'elem is not None' test instead.
  if curves_element:

(pitivi:22759): GStreamer-CRITICAL **: gst_segment_set_seek: assertion `start <= stop' failed

(pitivi:22759): GStreamer-CRITICAL **: gst_segment_set_seek: assertion `start <= stop' failed
ERROR [22759] [0x7f883255f720] "<Pipeline at 0x2441350>"        pipeline          Jan 28 20:40:27      _errorObject: error from /GstPipeline:pipeline0/GstBin:bin0/GnlComposition:gnlcomposition0/GnlSource:gnlsource: VideoTestSourceFactory2/GstBin:bin4/GstVideoTestSrc:videotestsrc0 (__main__.GstVideoTestSrc): GStreamer encountered a general stream error. (gstbasesrc.c(2563): gst_base_src_loop (): /GstPipeline:pipeline0/GstBin:bin0/GnlComposition:gnlcomposition0/GnlSource:gnlsource: VideoTestSourceFactory2/GstBin:bin4/GstVideoTestSrc:videotestsrc0:
streaming task paused, reason not-negotiated (-4)) (/usr/share/pitivi/python/pitivi/log/loggable.py:30)

(pitivi:22759): GStreamer-CRITICAL **: gst_event_new_new_segment_full: assertion `start <= stop' failed

(pitivi:22759): GStreamer-CRITICAL **: gst_event_new_new_segment_full: assertion `start <= stop' failed

(pitivi:22759): GStreamer-CRITICAL **: gst_event_new_new_segment_full: assertion `start <= stop' failed

(pitivi:22759): GStreamer-CRITICAL **: gst_event_new_new_segment_full: assertion `start <= stop' failed

(pitivi:22759): GStreamer-CRITICAL **: gst_event_new_new_segment_full: assertion `start <= stop' failed