Server Version#: 1.20.2.3402 (macOS 10.11.6)
Having the same problem, progress indicated but never completes. Looking at the command (below), server is trying to extract ~648 seconds (first half) of audio from the show in flac format.
“ps -ax -o pid -o etime -o command | egrep -i plex”
944 45:24 /Applications/Plex Media Server.app/Contents/MacOS/Plex Transcoder -codec:1 ac3 -analyzeduration 20000000 -probesize 20000000 -i /Users/~/Shows/Media/TV Shows/2 Broke Girls (2011)/Season 01/2 Broke Girls (2011) - S01E07 - And the Pretty Problem.mkv -filter_complex [0:1] aresample=async=1:ocl=‘5.1’:rematrix_maxval=0.000000dB:osr=48000[0] -map [0] -metadata:s:0 language=eng -codec:0 flac -b:0 4096k -f flac -map_metadata -1 -map_chapters -1 -t 648.78099999999995 /Users/~/Library/Caches/PlexMediaServer/Transcode/Detection/e152aefd-c72-48ef-a8ad-6239d83183d5 -y -nostats -loglevel quiet -loglevel_plex error -progressurl http~://127.0.0.1:32400/video/:/transcode/session/~~~/progress
The command syntax is on par with ffmpeg, except the exit pad label “[0]” for the filter_complex seems ill-formed. On attempt to replicate, ffmpeg returns the error: “Invalid encoder type ‘flac’.” Best guess is that “-map [0]” is meant to refer to the filter_complex output, but is seen as “-map 0” which refers to the first input. This causes “-codec:0 flac” to target a video stream, making flac an invalid format.
When I change the pad label from [0] to [pad], “-map [pad]” now targets the filter output (an audio stream) and ffmpeg makes it happen.
ffprobe result:
Input #0, flac, from ‘/Users/~/Desktop/2 Broke Girls’:
Metadata:
encoder : Lavf58.45.100
Duration: 00:10:58.11, start: 0.000000, bitrate: 2786 kb/s
Stream #0:0: Audio: flac, 48000 Hz, 5.1, s32 (24 bit)
Plex Transcoder is writing to the output file . . . very slowly, taking in excess of 45 min. Compared to <10 seconds using ffmpeg for half of a 20 min show.
-rw-r–r-- 1 user staff 105381888 Oct 13 12:31 20041671-e4fd-4a41-8b07-1bf32dad1cc9
-rw-r–r-- 1 user staff 141557760 Oct 13 12:48 20041671-e4fd-4a41-8b07-1bf32dad1cc9
ffprobe result: (incomplete file)
Input #0, flac, from ‘/Users/~/Library/Caches/PlexMediaServer/Transcode/Detection/20041671-e4fd-4a41-8b07-1bf32dad1cc9’:
Metadata:
encoder : Lavf58.27.104
Duration: N/A, start: 0.000000, bitrate: N/A
Stream #0:0: Audio: flac, 48000 Hz, 5.1, s32 (24 bit)