OK, so more experimentation. I deleted the video via the Plex Media Player. This removed the mkv file from the directory, but left the Thumbnail and Art files in the Media directory tree. So, they got nuked as well. >:)
Ran the following:
[root@Nethserver ~]# /usr/lib/plexmediaserver/Plex\ Media\ Scanner -s -r -c 5 --thumbOffset 1 --artOffset 1 -v -p
GUI: Scanning Formula1 (2017)
GUI: Scanning Formula1 (2017)
GUI: Scanning Formula1 (2017)
GUI: Scanning Formula1 (2017)
GUI: Scanning Formula1 (2017)
GUI: Scanning Formula1 (2017)
GUI: Scanning Formula1 (2017)
GUI: Scanning Formula1 (2017)
GUI: Scanning Formula1 (2017)
GUI: Scanning Formula1 (2017)
GUI: Scanning Formula1 (2017)
GUI: Scanning Formula1 (2017)
GUI: Matching 'Formula1'
GUI: Score for 'Formula1' (2017) is 100
GUI: Requesting metadata for 'Formula1'
GUI: Background media analysis on Formula1
GUI:
[root@Nethserver ~]#
Here’s the Scanner Log:
May 12, 2017 14:07:48.825 [0x7f10746d6700] INFO - Plex Media Scanner v1.5.5.3634-995f1dead - ubuntu PC x86_64 - build: linux-ubuntu-x86_64 - GMT -07:00
May 12, 2017 14:07:48.825 [0x7f10746d6700] INFO - Linux version: 3.10.0-514.16.1.el7.x86_64 (#1 SMP Wed Apr 12 15:04:24 UTC 2017), language: en-US
May 12, 2017 14:07:48.825 [0x7f10746d6700] INFO - Processor Intel(R) Xeon(R) CPU E3-1280 V2 @ 3.60GHz
May 12, 2017 14:07:48.825 [0x7f10746d6700] INFO - /usr/lib/plexmediaserver/Plex Media Scanner -s -r -c 5 --thumbOffset 1 --artOffset 1 -v -p
May 12, 2017 14:07:49.533 [0x7f1085cd9800] WARN - Held transaction for too long (../Library/MetadataItem.cpp:2796): 0.260000 seconds
May 12, 2017 14:07:49.997 [0x7f106e58c700] WARN - [FFMPEG] - Increasing reorder buffer to 1
May 12, 2017 14:07:50.211 [0x7f106e58c700] WARN - [FFMPEG] - Increasing reorder buffer to 1
May 12, 2017 14:07:50.845 [0x7f106e58c700] WARN - [FFMPEG] - Increasing reorder buffer to 1
May 12, 2017 14:07:51.121 [0x7f106e58c700] WARN - [FFMPEG] - Increasing reorder buffer to 1
May 12, 2017 14:07:51.725 [0x7f106e58c700] WARN - [FFMPEG] - Increasing reorder buffer to 1
May 12, 2017 14:07:52.032 [0x7f106e58c700] WARN - [FFMPEG] - Increasing reorder buffer to 1
May 12, 2017 14:07:52.343 [0x7f106e58c700] WARN - [FFMPEG] - Increasing reorder buffer to 1
But guess what. The re-generated Thumbnail and Art files were exactly as before, taken at (based on other comments) 25%, 50%, and 75%.
For good measure, I nuked the Thumbnails and Art yet again, and tried this:
[root@Nethserver ~]# /usr/lib/plexmediaserver/Plex\ Media\ Scanner -g -c 5 -o 6032 --thumbOffset 1 --artOffset 1 -v -p
Generated new media for Formula1.2017.Russian.Grand.Prix.Race.Session.1080p50.HDTV.x264.
[root@Nethserver ~]#
Oh dear, yet again it re-generated the Thumbnails and Art from 25%, 50%, and 75%.
So, with help from @sa2000 I can now run the scanner from the command line, but it isn’t doing what I want, so my beef with the “spoiler” Thumbnails and Art is still there.
Cheers.