SRT subtitles burned into the video when transcoding on a Samsung TV

Plex Media Server NAS & Devices
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Server Version#: 1.32.8.7639
Player Version#: Newest
Hello everyone.
Why are SRT subtitles burned into the video when transcoding on a Samsung TV, while on my Shield with the same playback bit rate setting they are played back without being burned in? You can see what I mean in the pictures. Actually, a Smart TV should be able to play SRT subtitles without burning in, right? The subtitle setting on the Smart TV is set to “never” burn in. If there are videos in HDR/DoVi, subtitles are switched on and the bandwidth limit is set, my server (DS918) goes to the limit and then constantly buffers. Why is that so?

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Not all Plex clients have the same capabilities.

I can’t help with specifics for the Samsung, but my LG has similar limitations (if video or audio is transcoding, subtitles are burned into the video).

The Plex Android TV client is one of the more capable clients. It does not require subtitle burning even if the video and/or audio is transcoding.

Regarding subtitle burning & the DS918+…

Subtitle burning currently uses the CPU, even when hardware transcoding is enabled. It is also single threaded, so it can only use one CPU core per video stream.

The process is:

  1. Decode video frame (hw accelerated)
  2. Add subtitle to video frame (using CPU)
  3. Encode video frame to H.264 (hw accelerated)

Simply put, the Celeron CPU in the NAS is not powerful enough to burn subtitles in real time. The client has to wait on it to process the frames, and the end-user experiences buffering.

It can burn subtitles for some lower bitrate 1080p video. Burning subtitles into 4K video is well beyond its capabilities.

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The shield has better subtitle codec support than most other client devices out there, it’s actually why I got one because I have a lot of old DVD rips with subtitles that couldn’t direct play to FireTVs back when I had a lower power CPU in my Plex server.

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Will it soon be possible to burn in the subtitles via hw?

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Plex has mentioned they are working on it. Delivery is sometime after the first of the year. Nothing about supported hardware, operating systems, etc. This is standard operating procedure for Plex. They rarely provide any public product plans, delivery dates, etc.

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