Question 1

What does this tool do?

Accepted Answer

Converts Sony BroadBook LRF ebooks to PDF in your browser. LRF is Sony's proprietary ebook format (used by the Sony Reader PRS-500, discontinued in 2011). We parse the LRF header (8-byte signature 'LRF' + zeros, version, object count, metadata offset), walk the object table (each entry: 4-byte type + 4-byte offset + 4-byte size + 4-byte id), extract text from TEXT-type objects, split into chapters by heading patterns, and render to PDF using pdf-lib.

Question 2

What is the LRF format?

Accepted Answer

LRF (Sony BroadBook, also called BBeB — Broad Band eBook) is Sony's proprietary ebook format. It uses a binary container with: (1) an 8-byte signature 'LRF' + 5 zeros; (2) a 4-byte version (usually 800-1000); (3) a 4-byte object count; (4) a 4-byte metadata offset; (5) an object table where each entry is 16 bytes: type (META=0, BOOK=1, PAGE=2, TEXT=3, IMAGE=4) + offset + size + id. Real LRF files use compressed objects and a complex PageTree/PageList structure; we support the DRM-free text-extraction path.

Question 3

Can it extract text from all LRF files?

Accepted Answer

Honest answer: most LRF files use object-level compression (a Sony variant of zlib) which we cannot decode in pure JavaScript without bundling a ~30KB+ decoder. We extract text from uncompressed TEXT-type objects only. If your LRF file uses compressed objects (most Sony-purchased books do), conversion may fail with 'no text objects found'. Use Calibre (desktop) to convert compressed LRFs to PDF — it has a complete LRF decoder.

Question 4

How does chapter detection work?

Accepted Answer

After extracting text from the TEXT objects, we look for heading patterns: Markdown-style '# Chapter 1', 'Chapter 1', 'Part 1', or ALL-CAPS lines (5+ chars). Each heading starts a new chapter. If no headings are found, the entire text becomes one chapter. The output PDF has chapter headings rendered in bold, with the body text in regular Helvetica.

Question 5

What extra features does this tool have compared to others?

Accepted Answer

10 extras: (1) Drag-drop file input. (2) LRF signature detection ('LRF' + zeros). (3) Object table parsing (type, offset, size, id). (4) Object type classification (META, BOOK, PAGE, TEXT, IMAGE). (5) Stats — object count, text object count, image count, page count, word count, PDF page count. (6) Custom title (defaults to LRF metadata title). (7) Adjustable font size (8-24pt). (8) Page size choice (US Letter or A4). (9) History (localStorage — last 10 conversions). (10) Shareable URL with options.

Question 6

Is my LRF file uploaded anywhere?

Accepted Answer

No. All LRF parsing and PDF generation runs in your browser using pure JavaScript + pdf-lib. File contents never leave your device. Only file summaries (filename, object count, word count) are saved to local history.

Question 7

Can I convert DRM-protected LRF files?

Accepted Answer

No. Sony's LRF DRM is proprietary and was discontinued when Sony shut down the Reader Store in 2014. Most free LRF downloads (Project Gutenberg, Baen Free Library) are DRM-free. If your LRF is DRM-protected, conversion will fail. For non-DRM LRFs that use compressed objects, use Calibre (desktop) which has a complete LRF implementation.

LRF to PDF Converter

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