CONVERT SUB → PDF (SUB to PDF)
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Ghostscript + QPDFHOW TO CONVERT SUB → PDF
Upload your SUB
Drop the document onto the uploader. We transfer over HTTPS and keep the file in an isolated processing container.
Render with LibreOffice
LibreOffice opens the SUB headlessly and writes it as PDF with styles, tables and images mapped across.
Download the PDF
The PDF is ready to download; typography, pagination and embedded assets match what you saw in the source.
Situation. SUB is a document format oriented around a particular office suite or publishing pipeline. Solution: a PDF, produced below. If you are staring at a SUB and need a clean PDF, retyping is never the answer — our converter routes the file through LibreOffice in headless mode and pandoc for text formats, which is the same pair of tools professional publishers rely on. Styles, tables, bullets and images all make it across. Worth knowing: SUB is a document format oriented around a particular office suite or publishing pipeline. Meanwhile PDF is Adobe's Portable Document Format, the fixed-layout standard for shareable documents.
Why convert SUB to PDF
SUB and PDF both describe paginated text, but they target different parts of the document life cycle. SUB is usually editable; PDF is usually final. Converting is about moving from editing to distribution (or the other way round) without losing headings, styles, tables or embedded images along the way.
SUB vs PDF — Technical specifications
Side-by-side comparison of the technical details.
SUB
- MIME type
- text/x-microdvd (MicroDVD); image/vnd.dvb.subtitle (VobSub)
- Extension
- .sub (paired with .idx for VobSub)
- Variants
- MicroDVD (text), VobSub (bitmap)
- Common conversion
- OCR VobSub → SRT
- MIME type
- application/pdf
- Current version
- PDF 2.0 (ISO 32000-2:2020)
- Compression
- Flate, LZW, JBIG2, JPEG, JPEG 2000
- Max file size
- ~10 GB (practical); 2^31 bytes (theoretical per object)
- Color models
- RGB, CMYK, Grayscale, Lab, DeviceN, ICC-based
- Standard subsets
- PDF/A, PDF/X, PDF/UA, PDF/E, PDF/VT
| Specification | SUB | |
|---|---|---|
| MIME type | text/x-microdvd (MicroDVD); image/vnd.dvb.subtitle (VobSub) | application/pdf |
| Extension | .sub (paired with .idx for VobSub) | — |
| Variants | MicroDVD (text), VobSub (bitmap) | — |
| Common conversion | OCR VobSub → SRT | — |
| Current version | — | PDF 2.0 (ISO 32000-2:2020) |
| Compression | — | Flate, LZW, JBIG2, JPEG, JPEG 2000 |
| Max file size | — | ~10 GB (practical); 2^31 bytes (theoretical per object) |
| Color models | — | RGB, CMYK, Grayscale, Lab, DeviceN, ICC-based |
| Standard subsets | — | PDF/A, PDF/X, PDF/UA, PDF/E, PDF/VT |
SUB vs PDF — Strengths and limitations
What each format does best, and where it falls short.
SUB Strengths
- VobSub preserves DVD subtitle appearance exactly.
- MicroDVD is trivially editable text.
- Universal player support (VLC, mpv, MPC).
- Historical format for DVD-era subtitle preservation.
Limitations
- Bitmap subtitles (VobSub) cannot be edited as text.
- MicroDVD frame-based timing breaks on framerate changes.
- Two incompatible formats sharing one extension causes confusion.
PDF Strengths
- Pixel-perfect fidelity across operating systems, browsers, and printers.
- Embeds fonts, so documents render identically without the reader having them installed.
- Supports digital signatures, encryption, and redaction for legal workflows.
- ISO-standardized (ISO 32000) with multiple validated subsets (PDF/A, PDF/X, PDF/UA).
- Supports both vector and raster content, keeping line art crisp at any zoom level.
Limitations
- Editing is difficult — the format is optimized for display, not mutation.
- Text extraction can scramble reading order in multi-column layouts.
- File sizes balloon quickly when embedding high-resolution images or fonts.
Quality & Compatibility
LibreOffice handles the heavy lifting and maps the overwhelming majority of SUB features to their PDF equivalents. Standard system fonts (Arial, Calibri, Times, Helvetica) transfer exactly; corporate or custom fonts are substituted with the closest available match, which can shift line breaks by a character or two. Inline images embed at original resolution.
Tips for Best Results
- Embed fonts in the SUB before uploading if you use non-system fonts — it guarantees the PDF renders identically on any viewer.
- Check tables, figure captions and page headers after conversion; complex layouts occasionally need a minor nudge in the target application.
- For documents with a table of contents, refresh the TOC field after opening the PDF so page numbers reflect the new pagination.
Frequently Asked Questions
Yes, as long as the fonts are standard (system fonts or common office fonts like Arial, Calibri, Times, Helvetica). Custom corporate fonts survive if they are embedded in the source document; otherwise the conversion substitutes the closest available match, which can shift line breaks by a character or two.
Yes. Inline images are embedded into the PDF at full resolution, editable tables become native PDF tables, and hyperlinks keep their URLs. Complex features unique to SUB — macros, form fields, track-changes — are mapped where an equivalent exists in PDF and flattened into static content otherwise.
All uploads go over TLS, files are processed in isolated containers and both the source and the output are deleted within two hours. No account is required, file contents are never indexed or used for training, and the paid plan adds a signable data-processing agreement for regulated workflows.
MicroDVD Subtitle
Source formatSUB (MicroDVD) is a subtitle format that uses frame numbers for timing instead of timestamps.
PDF Document
Target formatPDF is the universal standard for sharing documents with consistent formatting across all devices and operating systems. It preserves fonts, images, and layout exactly as intended by the author.
Common Use Cases
Share across platforms
Send PDF files to anyone without worrying about whether they have the right software for SUB.
Embed in documents
Drop PDF output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
PDF often produces smaller files than SUB for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
SUB vs PDF — Typical file sizes
Approximate file sizes for common scenarios.
- MicroDVD .sub for 2-hour movie 50-100 KB
- VobSub .sub (2-hour movie) 1-10 MB
- VobSub .idx metadata 50-200 KB
- 1-page text-only memo 50–150 KB
- 10-page report with images 500 KB – 2 MB
- Scanned document (per page) 100 KB – 1 MB
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Related comparisons
See these formats side by side to understand which fits your use case best.
Related Guides
PDF/X: The Complete Guide to Print-Ready PDF Standards
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