Convert sub/idx subpicture files to srt.
Sub/Idx, also called VobSub, is a subtitle format extracted from DVDs. It always comes as a matched pair of files: the .sub file holds bitmap images of the subtitle text, while the .idx file stores the timing and palette information needed to display them. Neither file works without the other.
This tool parses the MPEG program stream inside your .sub file, decodes each subtitle bitmap using the timing and palette data from the .idx file, and runs OCR using Tesseract.js to read the text from every image. Because each image has to be decoded and OCR'd individually, conversion can take a few minutes for a full movie.
A .sub file on its own can't be converted here — VobSub requires the matching .idx file. If you only have a .sub file, it may actually be a MicroDVD text subtitle file instead, which shares the same extension. Try the Convert to SRT tool to check.
A single sub/idx pair can contain more than one language, and sometimes the same language appears twice — once as regular subtitles and once as subtitles for the deaf and hard of hearing. Once your .idx file is loaded, this tool lets you pick which track to convert.
OCR-ing a sub/idx pair is CPU-intensive, so pairs can only be converted one at a time in the browser right now. A batch tool for converting many sub/idx pairs at once is planned as a premium feature backed by server-side processing — check back for updates.
All conversion is done locally in your browser. Your files are never uploaded to any server – they stay on your device.
Together they form VobSub — the DVD subtitle format. The .sub file holds bitmap images of every caption and the .idx file holds the timestamps, palette, and language-track list. Both files are required; neither converts on its own.
Select your .sub file and its matching .idx file on this page, choose the language track detected from the .idx, pick the OCR language, and click Convert to SRT. Decoding and OCR run entirely in your browser and the finished .srt downloads to your device.
The track dropdown lists every id found in your .idx (for example en, fr, or und). Convert the track matching your video's audio — DVDs often bundle a full track plus a deaf/hard-of-hearing track in the same language, so try the other same-language entry if captions look wrong.
Each caption image is decoded and OCR'd individually, so a full movie takes a few minutes depending on cue count and your device. Progress shows extraction first (20–40%) and then per-cue OCR (45–100%).
Clean DVD rips with the correct OCR language selected convert well. DVD bitmaps are lower resolution than Blu-ray, so stylised fonts, all-caps tracks, and italics need a quick proofread. Selecting the wrong OCR language is the most common cause of gibberish output.
A lone .sub file cannot be converted here because VobSub timing lives in the .idx. Re-rip or re-extract the DVD to get the pair. If the .sub is actually plain text with frame numbers (MicroDVD), use the Convert to SRT tool instead — it handles that text format.
They share an extension but nothing else: VobSub (.sub + .idx) is binary images from DVDs needing OCR, while MicroDVD (.sub alone) is text with frame numbers needing an FPS assumption. This page handles VobSub only.
Conversion preserves the .idx timestamps exactly, so drift means the video runs at a different frame rate than the DVD source. Run the finished SRT through the sync subtitles tool to shift or rescale it.
No. MPEG demuxing, bitmap decoding, and Tesseract.js OCR all run locally in your browser. Files over 150 MB are refused client-side with a pointer to desktop Subtitle Edit, rather than being uploaded.
Open the SRT beside your video and check cues near the beginning, middle, and end. Confirm the right language track was converted, dialogue order is intact, and the filename matches the video for auto-loading.
VLC plays VobSub tracks but cannot OCR image subtitles into text. Use this converter or desktop Subtitle Edit to recreate an SRT.
Keep the pair together with matching base names and open them in VLC or Subtitle Edit. For an editable, searchable file, convert the pair to SRT on this page first.
Yes — this tool is free with no signup. Browser OCR handles one pair at a time; batch-converting a whole DVD collection is faster in desktop Subtitle Edit.
DVDs commonly include a standard track plus a captioned/SDH track with sound labels like [DOOR CREAKS]. Both appear under similar ids — convert each and keep the one you prefer.
Short clips work on modern mobile browsers, but full movies are best converted on a desktop or laptop where OCR is much faster and less likely to run out of memory.
Blank results are skipped automatically. If nearly everything is blank, the wrong language track or OCR language is usually selected — retry with the other track or another OCR language.
Finished the DVD conversion? Fix timing, change format, or find the movie it belongs to:
Use this SUB/IDX to SRT OCR converter when you need to read image-based VobSub subtitle pairs and create editable SRT. The workflow is browser-based and the output is downloaded to your device.
Supported input or output formats for this workflow are a matching .sub and .idx VobSub pair with SRT output. The exact controls on the page determine which options apply.
This tool is designed for a focused subtitle workflow: read image-based VobSub subtitle pairs and create editable SRT. It reads the selected subtitle data in the browser, applies the chosen operation, and creates a downloadable result without requiring a separate desktop editor.
Start with the file type described in the tool controls and check that it belongs to the video you are working with. Keeping the original file lets you compare the result if a player interprets formatting or timing differently.
After downloading, load the output beside the matching video and verify a cue near the beginning, middle, and end. This catches format-specific timing or player-support differences before you archive the file.
The tool is intended for local browser processing. Your selected subtitle content is handled by the page and the generated file is downloaded locally; it is not presented as a server-side editing workflow.
Open this tool, select the relevant file, choose the available SUB/IDX to SRT OCR converter options, and download the generated result. The page keeps the workflow in the browser rather than requiring an installed editor.
Use the formats listed in the tool description and picker. a matching .sub and .idx VobSub pair with SRT output Formats outside that list may be rejected or need conversion first.
The tool is built for browser-side processing. Your file is selected by the browser and the result is downloaded locally rather than being described as a server upload.
No. Subtitle tools create or modify subtitle output only. The video itself is not edited, re-encoded, or downloaded by this workflow.
Open the downloaded file with a text editor or your video player. Confirm that cues are present, timestamps make sense, and the filename matches the video when automatic loading is useful.
Confirm the extension and file contents, then try a supported format such as SRT or VTT. If the file is an image subtitle or a video container, use the matching extraction or OCR tool instead.
Compatibility depends on the player and output format. SRT is a practical choice for broad device support, while WebVTT is intended for HTML5 video and browser-based players.
Yes. The workflow creates a separate download. Keeping the source is useful when you need to repeat the operation with different settings or preserve styling that an output format cannot store.