# LG webOS Plex: "Playback Error" when a subtitle is selected

**URL:** <https://forums.plex.tv/t/lg-webos-plex-playback-error-when-a-subtitle-is-selected/943714>\
**Category:** Plex Players\
**Tags:** lg-webos\
**Created:** [September 30, 2026, 3:52pm UTC](https://forums.plex.tv/t/lg-webos-plex-playback-error-when-a-subtitle-is-selected/943714 "2026-09-30T15:52:50Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![lazywerebear](https://avatars.discourse-cdn.com/v4/letter/l/74df32/32.png) [@lazywerebear](https://forums.plex.tv/u/lazywerebear)\
**Post date:** [September 30, 2026, 3:52pm UTC](https://forums.plex.tv/t/lg-webos-plex-playback-error-when-a-subtitle-is-selected/943714/1 "2026-09-30T15:52:50Z")

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Server Version#: 1.43.4.10903  
Player Version#: (Client) 5.94.3, (Platform) 10.3.1

## Symptom

TV Shows shows with subtitles turned on show “Playback Error - An unexpected playback error occurred” almost immediately on my LG TV. The same files play fine on iOS, iPad and a Samsung Frame (with ASS, PGS and SRT subtitles).

## Environment

- TV: LG OLED83C4AUA, webOS 10.3.1, Plex for LG 5.94.3 (reinstalling the app did not help)
- Server: Plex Media Server on Windows, NVIDIA hardware transcoding (nvdec/nvenc) working

## Findings (from [server logs)](https://support.plex.tv/articles/200250417-plex-media-server-log-files/)

- With subtitles set to None, the file plays (HLS direct stream, audio transcoded from Opus). Opus and 10-bit HEVC are not the problem.
- With any subtitle selected, the LG app sends `subtitles=burn` and playback fails. Tested and failing: embedded ASS, embedded SRT (converted with ffmpeg), sidecar .srt, at 1080p and at 720p/4 Mbps.
- A re-encode without a subtitle (720p, subtitles None) works, so re-encoding itself is fine.
- Failure signature: the TV’s requests for `/video/:/transcode/universal/session/<id>/base/index.m3u8` reach the server as `ET /video/...` (first byte missing), Plex logs “Error parsing HTTP request”, returns 400 (11 times in ~70 ms), the transcoder never starts, and the client reports `state=stopped`.

## Not established

Why the TV’s player produces malformed requests only in the burn-in case. Cause is presumed to be a client-side bug in Plex for LG or webOS, but this is inference.

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**Author:** ![MovieFan](https://avatars.discourse-cdn.com/v4/letter/m/779978/32.png) [@MovieFan](https://forums.plex.tv/u/MovieFan)\
**Post date:** [September 30, 2026, 8:07pm UTC](https://forums.plex.tv/t/lg-webos-plex-playback-error-when-a-subtitle-is-selected/943714/2 "2026-09-30T20:07:39Z")

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Do you possibly have transcoding disabled on the server?