Same TV series recorded OTA. I rip out the subtitles as .srt and place then into the resulting transcoded stream H264 AAC mp4.
When I play in Plex on ones that work, they say the subtitle stream is of type TX3G, and on ones that fail says they are MOV_TEXT. That's how Plex sees them when I try to turn on the subtitles. Same ffmpeg line for each... nothing different except that sometimes Plex sees as TX3G (works) and sometimes MOV_TEXT (doesn't work). Does anyone know a secret, something else I need to add?
Example ffmpeg line:
/usr/bin/ffmpeg -threads 0 -i OriginalFile.ts -f srt -i /tmp/OriginalFile.eng.srt -bsf:a aac_adtstoasc -c:v copy -c:a copy -c:s mov_text -metadata:s:s:0 language=eng -metadata:s:a:0 language=eng "./TV/Criminal Minds: Suspect Behavior/Season 1/Criminal Minds: Suspect Behavior - s01e13 - Death by a Thousand Cuts.mp4"