FB2 → CBZ/CBR

What is FB2?

FB2 (FictionBook 2) is an open XML-based e-book format that is very popular in Russian-speaking regions. Body text, metadata and illustrations all live in one XML file, with images usually embedded as Base64, so a single .fb2 is a complete book that is easy to distribute. It has clean structure and carries chapters and author data natively; the drawbacks are larger size (Base64 inflates images by roughly a third) and less reader support outside Russian-language markets.

What is CBZ/CBR?

A comic book archive is not a real format but a folder of images packed in order: .cbz is ZIP, .cbr is RAR, .cbt is TAR and .cb7 is 7z, renamed so readers recognise it. There is no text layer and no typography — each page is a single full-page image, and reading order comes from filename sorting (which is why unpadded names like 1.jpg, 2.jpg … 10.jpg put page 10 right after page 1).

What to watch out for when converting FB2 to CBZ/CBR

Extracting from the source

FB2 is a single XML file with Base64-embedded images. Parsing must handle the XML namespace and <binary> nodes; ignoring them silently drops every image. Base64 also makes the file roughly a third larger than an equivalent EPUB.

Writing the target format

Converting to a comic archive really just packs images under ordered names; all text is discarded. Zero-pad the filenames (001.jpg, 002.jpg) so sorting works, and note that .cbr needs RAR tools while most readers handle .cbz (ZIP) best.

Where the two formats interact

• Reflow is lost: the target freezes the layout, so readers can no longer change font size or line width. Long novels become zoom-and-pan on small screens — the most common reason a conversion ends up harder to read. Unless you need print or layout-critical delivery, keep a reflowable copy for reading.
• The target is image-only: all text in the source is discarded (or survives only as pixels). If your goal is content that can be searched, copied or read aloud, this direction is wrong — pick a text-preserving target instead.
• The source carries real navigation while the target has no concept of chapters, so reading becomes one long scroll. If navigation still matters, keep explicit, uniformly formatted chapter heading lines in the output.
• Going from a single text file to a structured archive adds information: the tool must generate the manifest, the navigation document and metadata for you. The quality of those generated parts — accurate chapter splitting, correct language tags — decides whether the result is usable.

Post-conversion checklist

1. Convert the first three chapters as a trial and check for lost text, interleaved lines or misplaced blocks before doing the whole book.
2. Confirm illustration count and placement — check that images are not all dumped at the end of a chapter.
3. Fill in title, author and language — a wrong language tag breaks typesetting such as Chinese line breaking.

Converting novels: what is different

Fiction is the most common and the most peculiar kind of e-book: hundreds or thousands of chapters, almost no figures, often nothing but a TXT source, and Chinese sources that frequently carry anti-piracy garbling. These are the points that bite hardest.

• The target has no notion of a table of contents, and not being able to jump to a chapter is the worst part of reading something long. If you will keep reading it, keep a navigable copy as well (EPUB or Kindle) and treat this one as the distribution or archive copy.
• Once a long novel is in a fixed layout, reading on a phone means zooming and panning. Fiction is the worst fit for fixed layout of any genre: almost no figures, all continuous text. Unless you are printing or submitting it, prefer a reflowable format for novels.
• Volume markers ("Volume One", "Volume Two") usually degrade to ordinary headings, losing the volume/chapter hierarchy. If that matters, promote volume headings one level in an editor afterwards so they are not siblings of chapter titles.

Tools for converting FB2 to CBZ/CBR

Any of the tools below can handle this direction; pick one by your operating system and how many files you have. Read the previous section first — doing the steps out of order (converting a scanned file before running OCR, for instance) usually means starting over.

Common questions

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