Mar 07, 2020 11:43:22.213 [0x7f48d6526700] INFO - Plex Media Server v1.18.7.2457-77cb9455c - Debian GNU/Linux PC x86_64 - build: linux-x86_64 debian - GMT 01:00
Mar 07, 2020 11:43:22.214 [0x7f48d6526700] INFO - Linux version: 10 (buster), language: en-IE
Mar 07, 2020 11:43:22.214 [0x7f48d6526700] INFO - Processor Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz
Video is HEVC, the CPU does not support HEVC in hardware
Mar 07, 2020 13:25:36.740 [0x7f48957fa700] DEBUG - Audio Stream: 3379, Subtitle Stream: 3382
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: Selected protocol http; container: ass
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: analyzing media item 2920
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: How to Train Your Dragon: The Hidden World (2019): selected audio stream is not the first audio stream and direct play stream selection is not enabled
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: How to Train Your Dragon: The Hidden World (2019): no direct play video profile exists for http/mkv/hevc
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: How to Train Your Dragon: The Hidden World (2019): no direct play video profile exists for http/mkv/hevc/truehd
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: How to Train Your Dragon: The Hidden World (2019): transcoding selected subtitle stream
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: How to Train Your Dragon: The Hidden World (2019): no direct play video profile exists for http/mkv/hevc/dca
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: How to Train Your Dragon: The Hidden World (2019): transcoding selected subtitle stream
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: How to Train Your Dragon: The Hidden World (2019): no direct play video profile exists for http/mkv/hevc/ac3
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: How to Train Your Dragon: The Hidden World (2019): transcoding selected subtitle stream
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: How to Train Your Dragon: The Hidden World (2019): no direct play video profile exists for http/mkv/hevc/ac3
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: How to Train Your Dragon: The Hidden World (2019): transcoding selected subtitle stream
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - How to Train Your Dragon: The Hidden World - audio.channels limitation applies: 8 > 6
Mar 07, 2020 13:25:36.741 [0x7f48957fa700] DEBUG - MDE: How to Train Your Dragon: The Hidden World (2019): selected media 0 / 2920
Mar 07, 2020 13:25:36.742 [0x7f48957fa700] DEBUG - Streaming Resource: Added session 0x7f487c0d2490:i1csrlo0an7s1t7vcolg6p1a
Mar 07, 2020 13:25:36.742 [0x7f48957fa700] DEBUG - Streaming Resource: Reached
Audio transcoding is adding to the load in addition to transcoding HEVC -> H264 (extremely CPU intensive - nearly impossible by a CPU)
EDIT: If this is really playing as DirectPlay , it issue is in the client or networking. This would contradict what the player reports as the decision made.
Keep in mind the limitations of the Plex SmartTV app:
Enabling image based subtitles, PGS or VOBSUB, forces a video transcode.
If the audio is also transcoding, enabling text based subtitles also forces a video transcode.
The TV does not support, and will always transcode, TrueHD audio. If possible, choose a Dolby Digital (AC3) or dts audio track instead. Blu-ray discs with TrueHD audio tracks also have an AC3 version of the audio tracks.
You should avoid transcoding 4K video when possible. As @ChuckPa mentions, this puts an enormous load on the CPU. If it cannot keep up, you will see buffering. In addition, if the video is HDR, the transcode process will discard the HDR information. The Plex transcoder does not map HDR to SDR, to the resulting video may look quite poor, with washed out colors.
Since you both found out the issue causing the buffering, I marked your answers as the solution to my question.
However, I have to note the following. I made a mistake in the title, I am actually watching on the more high-end LG OLED B8 64". Forgive me for the typo, I seem to be unable to change the title. @FordGuy61 for that reason, TrueHD audio support should not be the issue causing the transcoding. And as you mentioned, subtitles can indeed force full transcoding, just like audio (noticed this before and read about that on the forum). However, since I know about this issue, I am always selecting SRT subs in the player.
So I did a new discovery! For some reason, it needs to fully transcode the movie when I choose the first (automatically preferred) SRT subtitle, while there is a second one beneith it that looks exactly the same “English (SRT)” which can be played directly on the TV without transcoding! This does not make any sense at all, and I remember having this same issue back in the day when watching another movie. I will try to investigate this further, but if any of you knows the reason for this, please let me know!
