How to Convert SUP to SRT
SUP (PGS) subtitle files are image-based, meaning the text is stored as pictures rather than characters. To convert sup to srt online, upload your file, select the subtitle language, and click Convert. The tool uses OCR to read each image and output a standard SRT text file, all inside your browser with no upload to any server.
- Upload your SUP (PGS) file
- Select subtitle language
- Click Convert
- Download your SRT file
What Are SUP and SRT Subtitles?
SUP (PGS) Format
SUP files are PGS (Presentation Graphic Stream) subtitles used on Blu-ray discs. They are image-based, meaning each subtitle is a bitmap picture, not readable text. SRT is a plain text format. Because SUP stores images instead of characters, OCR is required to read the content and convert it into an editable SRT file.
The .sup file extension signals PGS or Blu-ray subtitle data. These files are binary and read-only by design. A typical feature film SUP file contains hundreds of individual subtitle images packed together with precise timing data.
SRT Format
SRT (SubRip Text) is the most widely supported subtitle format. It stores subtitles as plain text with timestamps. You can open and edit an SRT file in any text editor. Every major media player, video editor, and streaming platform accepts SRT natively without additional software.
How OCR Conversion Works
This tool uses Optical Character Recognition to read each subtitle image and extract the visible text. It works for both SUP and PGS to SRT conversion, since SUP and PGS are the same format. The result is a properly timed SRT file that matches the original subtitles frame by frame. All recognition happens inside your browser. Nothing is sent to a server.
Why Use This Converter
- Completely free. No account, no subscription, no hidden charges of any kind.
- 100% browser-based. Your files never leave your device. There are no server uploads, ever.
- Fast and accurate OCR. Powered by Tesseract OCR with 95 to 99 percent accuracy for Latin-script languages.
- 40 plus languages supported. English, Spanish, French, German, Japanese, Arabic, Chinese, Hindi, and many more.
- Three OCR profiles. Choose Fast, Balanced, or Accurate depending on your priority.
- Works on all devices. Use this SUP to SRT converter online from Windows, Mac, Linux, or any modern browser. No installation needed.
- Automatic language detection. The tool reads your filename and selects the correct OCR language automatically.
- Post-processing built in. Remove OCR artifacts, normalize punctuation, preserve line breaks, or filter forced captions with a single click.
Why Convert SUP to SRT?
Edit and Translate Subtitles
SRT files are plain text. Once you convert from SUP, you can open the file in any text editor and change wording, fix errors, or resync timing. This is the standard workflow for subtitle translators and editors worldwide.
PGS subtitles are locked as images. There is no way to change a single word without converting to a text format first.
Compatibility With Players and Editors
Most video editors, media players, and streaming platforms support SRT natively. Upload SRT to YouTube, load it in VLC, embed it in Plex or Jellyfin, or use it directly in DaVinci Resolve and Adobe Premiere.
SUP files require specialized software to play or process. Converting to SRT removes that dependency entirely.
Smaller File Size
A typical SUP file is 1 to 10MB because it stores images. The equivalent SRT file is usually under 100KB. Text-based subtitles are faster to load, easier to share, and simpler to work with.
When Do You Need to Convert SUP to SRT?
- Extract subtitles from MKV files. MKV files often contain embedded PGS subtitle tracks. Convert them to SRT to make the subtitles editable and universally compatible.
- Edit subtitle text or timing. SRT is plain text. Once converted, open the file in any editor and make changes directly.
- Translate subtitles. Translators work with text, not images. Converting SUP to SRT is the first step in any subtitle translation workflow.
- Use subtitles in VLC, Plex, or Jellyfin. These players load SRT files natively. PGS subtitles require transcoding; SRT enables direct play on all devices.
SUP vs SRT: Key Differences
| SUP Format | SRT Format | |
|---|---|---|
| Type | Image-based (bitmap graphics) | Text-based (plain text) |
| Editable | No (requires special tools) | Yes (any text editor) |
| File Size | Large (typically 1 to 10MB) | Small (typically 10 to 100KB) |
| Source | Blu-ray, HD-DVD | Streaming, websites, editors |
| Font Rendering | Perfect (stored as image) | Depends on the player |
| Editing Tools | BDSup2Sub, SupReader | Aegisub, Subtitle Edit, any text editor |
The core difference is straightforward. SUP stores what subtitles look like. SRT stores what subtitles say. For editing, translating, or playing subtitles in any application, SRT is the better choice.
Common Use Cases
Extract Subtitles from MKV Files
MKV containers often bundle PGS subtitle tracks from Blu-ray sources. Extract the subtitle stream with MKVToolNix or FFmpeg, then convert the resulting SUP file here to get a usable SRT track.
Edit Subtitle Text and Timing
Once converted to SRT, open the file in Aegisub or Subtitle Edit to adjust timing, fix typos, or merge and split lines. This is not possible to do directly on a SUP file.
Translate Subtitles to Another Language
Professional translators need editable text to work with. Convert the source SUP file to SRT, run your translation on the plain text content, and deliver a finished SRT in the target language.
Use Subtitles in Any Media Player
VLC, Plex, Jellyfin, Kodi, and virtually every media player support SRT files directly. SUP playback requires specific software. Converting once gives you full compatibility across all your devices.
Reduce Transcoding Load on Media Servers
Plex and Jellyfin transcode PGS subtitles on the fly, which uses significant CPU resources. Switching to SRT eliminates that overhead and enables direct play on every device in your home.
How to Extract SUP Files Before Converting
If your subtitles are still inside an MKV or on a Blu-ray disc, you need to extract them first. Use one of these tools:
- MKVToolNix: Open your MKV file, select the subtitle track, and extract it as a .sup file.
- FFmpeg: Run
ffmpeg -i input.mkv -map 0:s:0 output.supto extract the first subtitle stream. - HandBrake: Rip a Blu-ray disc and select the subtitle track to export during the process.
- BDSup2Sub: A dedicated Blu-ray subtitle extraction and conversion tool.
Once you have the .sup file, upload it to the converter above and follow the steps.
Troubleshooting Common Issues
OCR Errors or Garbled Text
Most OCR errors come from the wrong language setting. If the output looks like random characters, check that the selected language matches the language in the SUP file. Then try the Accurate OCR profile for better recognition on difficult fonts.
Wrong Language Detected Automatically
Automatic language detection reads your filename. If the filename does not contain a language code, the tool defaults to English. Override it manually by selecting the correct language from the dropdown before converting.
Timing Looks Correct but Text Is Wrong
Timing data is read directly from the PGS stream, so timestamps are almost always accurate. Text errors come from OCR. Review the converted SRT file and correct any misread words using a text editor or subtitle editor.
Processing Is Very Slow
Large SUP files with many subtitle events take longer to process. Switch to the Balanced or Fast OCR profile to reduce processing time. The Accurate profile is slower by design because it runs additional recognition passes.
Convert Subtitles PGS (SUP) to SRT with different tools
Quick links for common queries:
Convert SUP to SRT Online Now
Upload your SUP (PGS) file and get SRT instantly. No account, no installation, no upload to any server.
Frequently Asked Questions
What is a SUP file?
A SUP file stores Blu-ray subtitles in PGS (Presentation Graphic Stream) format. Each subtitle is saved as a bitmap image rather than text, which is why you need OCR to convert the content to an editable format like SRT.
Is SUP the same as PGS?
Yes. SUP and PGS refer to the same format. PGS is the technical name (Presentation Graphic Stream) while SUP is the file extension. Both terms describe the same image-based subtitle format used on Blu-ray discs. This tool converts both identically.
How accurate is the SUP to SRT conversion?
Accuracy depends on language, font quality, and image resolution. English and other Latin-script languages typically achieve 95 to 99 percent accuracy. Languages with complex scripts such as Chinese, Japanese, and Korean usually see 75 to 90 percent accuracy. Always review the converted SRT file before use in professional projects.
Can I convert SUP to SRT on Mac or Linux?
Yes. This tool runs entirely in your browser, so it works on Windows, Mac, Linux, and any operating system with a modern browser. No installation is needed. Many desktop subtitle tools are Windows-only, but this converter has no platform restrictions.
Is this tool free to use?
Yes, completely free. There are no hidden charges, no premium tiers, and no file size paywalls beyond the 100MB browser limit. All processing happens on your device at no cost.
Do I need to install any software?
No installation required. Open the page in your browser, upload your SUP file, and convert. The OCR engine loads once from a CDN and runs locally via WebAssembly. Nothing is installed on your system.
What if the converted text has errors?
OCR is not perfect. If you see incorrect characters or words, try switching to the Accurate OCR profile and make sure the correct language is selected. After converting, open the SRT file in any text editor or subtitle editor such as Aegisub or Subtitle Edit to fix any remaining errors manually.
Can I convert PGS to SRT using this tool?
Yes. Upload any .sup or .pgs file and the converter handles it the same way. PGS and SUP are the same underlying format regardless of file extension.
Can I convert multiple SUP files at once?
The tool processes one file at a time. For bulk conversion, you can use FFmpeg combined with Tesseract OCR from the command line, or use BDSup2Sub which supports scripted batch workflows.