How to Convert PGS (SUP) to SRT for Plex
Plex has built-in subtitle extraction for PGS and SUP tracks, but manual pre-conversion gives you control over accuracy. Pre-converted SRT files also enable direct play on more Plex clients without any server processing.
- Upload your SUP (PGS) file
- Select subtitle language
- Click Convert
- Download your SRT file
Why PGS and SUP Subtitles Cause Transcoding in Plex
How Plex Handles PGS and SUP Subtitle Tracks
When a Plex client requests a video with PGS or SUP subtitles, the Plex Media Server burns the subtitle images into the video stream in real-time. This forces transcoding even when the video codec would otherwise support direct play. On mid-range NAS devices, PGS-forced transcoding causes buffering and high CPU load.
Plex has a built-in subtitle extraction feature that can process PGS/SUP tracks automatically using the pgs2srt utility on the server side. However, this runs on first playback, consumes significant CPU, and results vary by Plex version. Pre-converting with this browser tool gives you consistent quality and no first-play delay.
SRT Enables Direct Play in Plex
Text-based SRT subtitles are handled by the Plex client device, not the server. The server sends the SRT file directly to the client, and the client renders the text overlay without any server processing. This enables direct play for the video stream at full quality, eliminating the transcoded re-encode entirely.
Set Up SRT Subtitles for Plex After Converting PGS
File Naming and Placement
Name the converted SRT file to match your video: Movie Title (Year).en.srt for English, Movie Title (Year).es.srt for Spanish. For TV series: Show Name - S01E01.en.srt. Place the .srt file in the same folder as the video.
After adding the file, trigger a library refresh in Plex (three-dot menu on the library → Scan Library Files). Plex detects the new external subtitle file and makes it available in the subtitle track selection menu.
Keeping Both PGS and SRT in Plex
You can keep the original PGS track in the MKV alongside the external SRT file. Plex offers both subtitle options in the track menu. This is useful if OCR accuracy is imperfect — viewers can switch between the original PGS (image) and the converted SRT (text) versions.
Plex Subtitle Searches
Plex users converting PGS subtitles also search:
Convert PGS (SUP) to SRT for Plex Now
Upload your .sup file and get an SRT file ready for Plex direct play. No account, no installation, no upload to any server.
Frequently Asked Questions
Does Plex Pass include automatic PGS/SUP to SRT conversion?
Plex has included varying levels of automatic subtitle extraction in some Plex Pass tiers. For consistent quality and accuracy, manual pre-conversion with this browser tool is more reliable than Plex's automated extraction.
What Plex clients support SRT subtitles for direct play?
All Plex clients support SRT subtitles — web, Android, iOS, Apple TV, Roku, Fire TV, Samsung TV, LG TV, Xbox, PlayStation, and desktop apps. SRT is the most universally compatible subtitle format in the Plex ecosystem.
Does Plex prefer external SRT files or internal PGS subtitle tracks?
Plex supports both, but external SRT files enable direct play across more clients and reduce server load. For best compatibility and performance, pre-converted SRT is recommended over relying on Plex's built-in PGS/SUP handling.
Why does my Plex server use 100% CPU when playing a video with PGS subtitles?
PGS and SUP subtitles force Plex to transcode the video in real-time to burn subtitle images into each frame. Converting the PGS track to SRT before adding the video to Plex eliminates this transcoding requirement entirely.