Comment 14 for bug 1504079

Also happening in 17.04. Started happening after a fsck repair following a power failure. Could be related to lost/corrupt files.

Running tracker-extract manually on file shown in syslog gives the following.

roger@dragon:~/Documents/Old Stuff/Camtasia Studio$ tracker extract --verbosity=detailed visualimpact.avi
Tracker-Message: Starting tracker-extract 1.12.0
Tracker-Message: General options:
Tracker-Message: Verbosity ............................ 2
Tracker-Message: Sched Idle ........................... 1
Tracker-Message: Max bytes (per file) ................. 1048576
Setting priority nice level to 19
Loading extractor rules... (/usr/share/tracker/extract-rules)
Extractor rules loaded
MIME type guessed as 'video/x-msvideo' (from GIO)
gst_video_info_set_format: assertion 'format != GST_VIDEO_FORMAT_UNKNOWN' failed
gst_video_info_to_caps: assertion 'info->finfo->format != GST_VIDEO_FORMAT_UNKNOWN' failed

(tracker-extract:5311): GStreamer-CRITICAL **: gst_mini_object_unref: assertion 'mini_object != NULL' failed
Call to gst_discoverer_discover_uri(file:///home/roger/Documents/Old%20Stuff/Camtasia%20Studio/visualimpact.avi) failed: Unable to allocate memory
file:///home/roger/Documents/Old%20Stuff/Camtasia%20Studio/visualimpact.avi: No metadata or extractor modules found to handle this file

There is an interesting comment in the man page for tracker-extract.

"The actual extraction is done by a separate process. This is done to isolate the calling process from any memory leaks or crashes in the libraries Tracker uses to extract metadata."