The transcoder is failing because it is getting an error on setting up the segments list
Dec 19, 2018 08:15:55.714 [4852] ERROR - [Transcoder] [stream_segment,ssegment @ 04159b40] Failed to open segment list 'http://127.0.0.1:32400/video/:/transcode/session/A56E5216-9CE9-4EA1-8C06-5BEA1BB49FC7/6ca5f425-af3b-4333-ae9c-1012675b0f79/seglist'
Dec 19, 2018 08:15:55.714 [18248] ERROR - [Transcoder] av_interleaved_write_frame(): Unknown error
Dec 19, 2018 08:15:55.761 [15068] ERROR - [Transcoder] Error writing trailer of media-%05d.ts: Invalid argument
Dec 19, 2018 08:15:55.814 [10956] DEBUG - Jobs: 'C:\Program Files (x86)\Plex\Plex Media Server\PlexTranscoder.exe' exit code for process 11592 is 1 (failure)
Dec 19, 2018 08:15:55.814 [8660] DEBUG - Streaming Resource: Terminated session 0xae25ed8:DF659705-5E16-4A70-A90E-44D1556F46A9 with reason Conversion failed. The transcoder exited due to an error.
and
Dec 19, 2018 08:26:03.308 [14416] ERROR - [Transcoder] [stream_segment,ssegment @ 04089b00] Failed to open segment list 'http://127.0.0.1:32400/video/:/transcode/session/A9D9077F-225F-4B4F-88B4-F82E611E3B7F/47710672-e959-49d6-a1be-d1d5814456cc/seglist'
Dec 19, 2018 08:26:03.308 [12904] ERROR - [Transcoder] av_interleaved_write_frame(): Unknown error
Dec 19, 2018 08:26:03.355 [14416] ERROR - [Transcoder] Error writing trailer of media-%05d.ts: Invalid argument
Dec 19, 2018 08:26:03.397 [19048] DEBUG - Jobs: 'C:\Program Files (x86)\Plex\Plex Media Server\PlexTranscoder.exe' exit code for process 2568 is 1 (failure)
Dec 19, 2018 08:26:03.397 [4328] DEBUG - Streaming Resource: Terminated session 0xbadc168:DF659705-5E16-4A70-A90E-44D1556F46A9 with reason Conversion failed. The transcoder exited due to an error.
These type of errors were last seen when Microsoft released a faulty Windows 10 Update in July 2018 which they corrected with a further update a few days later.
For some reason the errors have surfaced again and there are diagnostics from other user that are being investigated by the Plex Media Server development team.- See my post here Recording failed. Please check your tuner or antenna - #68 by sa2000
If you can easily reproduce these errors, you could try and get similar diagnostics to what @ben-page provided and i will pass to the development team in case it has some extra clues
The specific diagnostics needed is a loopback packet capture on the machine and rawcap.exe has been suggested by me. If you do provide that with logs, please upload to dropbox or google drive etc and send me link by Private Message
Details of the required diagnostics are given in the forum thread I linked
