Plex transcodes video when transcoding audio and using subtitles

Plex Media Server NAS & Devices
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Server Version#: 1.31.3.6868
Player Version#: 5.59.3
Plex Media Server Logs_2023-04-23_12-39-38.zip (264.3 KB)

Context:
The LG C2 supports AC3 but does not support DTS audio.
Plex for LG supports PGS subtitles natively.

Reproduction steps:

  1. Play a file with DTS audio and no subtitles
  2. Play a file with DTS audio and PGS subtitles
  3. Play a file with AC3 audio and PGS subtitles

Actual results:

  1. Only audio is transcoded
  2. Both video and audio are transcoded
  3. Nothing is transcoded

Expected results:

  1. Only audio is transcoded
  2. Only audio is transcoded
  3. Nothing is transcoded
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See here:

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Can you verify #3?

TrueHD audio, with or without subtitles, should be transcoded by Plex Media Server.

TrueHD is not listed as a supported audio format in the C2 specs (LG).

No known TV, LG or other, supports passthrough of TrueHD audio from a TV based app.

The C2 will passthrough TrueHD from a device attached to an HDMI input, but TrueHD audio from a TV based app should transcode.

5

You’re right. It had actually selected the AC3 track. I have edited the first post.
My point was that the app does not transcode just because of subtitles.

6

Thanks for verifying.

Yes. It is subtitles + direct streaming. It has been that way for a long time, at least since I bought my B7 OLED several years ago. Hopefully some day Plex can get it working w/o video transcoding.

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