PDF vs SUB
A detailed comparison of PDF Document and MicroDVD Subtitle — file size, quality, compatibility, and which format to choose for your workflow.
PDF Document
Documents & TextPDF 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.
About PDF filesMicroDVD Subtitle
Documents & TextSUB (MicroDVD) is a subtitle format that uses frame numbers for timing instead of timestamps.
About SUB filesStrengths Comparison
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.
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
PDF 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.
- Accessibility (screen readers) requires careful tagging that many PDFs skip.
- JavaScript support has historically been a malware vector.
SUB 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.
- Superseded by SRT and ASS for editing and modern streaming.
Technical Specifications
| Specification | SUB | |
|---|---|---|
| MIME type | application/pdf | text/x-microdvd (MicroDVD); image/vnd.dvb.subtitle (VobSub) |
| 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 | — |
| Extension | — | .sub (paired with .idx for VobSub) |
| Variants | — | MicroDVD (text), VobSub (bitmap) |
| Common conversion | — | OCR VobSub → SRT |
Typical File Sizes
- 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
- Full-color magazine (48 pages) 10–40 MB
SUB
- MicroDVD .sub for 2-hour movie 50-100 KB
- VobSub .sub (2-hour movie) 1-10 MB
- VobSub .idx metadata 50-200 KB
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Frequently Asked Questions
PDF (Portable Document Format) was created by Adobe in 1993 to present documents consistently across all devices and operating systems. It preserves fonts, images, layouts, and formatting regardless of the software used to view it.
SUB (MicroDVD Subtitle) is a document format used to store paginated text, with optional formatting, tables, images, hyperlinks, headers and footers. It sits in the documents & text family and is typically associated with a specific office suite or publishing pipeline that defined the format and ships the canonical reader.
PDF files can be opened with Adobe Acrobat Reader (free), web browsers like Chrome and Edge, macOS Preview, and alternative readers like Foxit and Sumatra PDF.
Modern office suites — Microsoft Word, Google Docs, LibreOffice Writer, Apple Pages — open most SUB files with reasonable fidelity. If your installed software does not support SUB, convert to DOCX or PDF first using KaijuConverter; both open in virtually every reader, including free online viewers.
Use PDF for final documents meant to be viewed or printed without changes. Use DOCX when the document needs to be edited collaboratively. PDF preserves exact layout while DOCX allows flexible editing.
Upload the SUB to KaijuConverter and pick DOCX, PDF, ODT, RTF, HTML, Markdown, or plain text. Our pipeline runs LibreOffice headlessly plus pandoc for text formats — the same engines behind professional document pipelines. Styles, tables, images, and hyperlinks survive the conversion intact.