FB2 to HDR Converter
FileFlip converts FB2 to HDR entirely inside your browser, using Pandoc, MuPDF and ImageMagick compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert an FB2 file to HDR?#
- Drop your FB2 file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to HDR and the conversion starts on its own. FileFlip downloads 79.9 MB of WebAssembly the first time and nothing after that, then runs Pandoc, MuPDF and ImageMagick on your own machine.
- Save the HDR file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting FB2 to HDR lose quality?#
Yes, in the sense that text stops being text. Each FB2 page is rendered to pixels and handed to HDR, so the result looks right and can no longer be selected, searched, or reflowed.
Is it safe to convert FB2 files online?#
Yes, because nothing is uploaded. FileFlip converts FB2 files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What FB2 to HDR actually does to the file#
Converting FB2 to HDR runs on Pandoc, MuPDF and ImageMagick, downloads 79.9 MB of WebAssembly the first time and nothing after that, renders each page to pixels, keeps page layout, and drops selectable text and transparency.
| Engine | Pandoc, MuPDF and ImageMagick |
|---|---|
| Conversion path | 3 steps: FB2 → HTML → PNG → HDR |
| Downloaded to your browser | 79.9 MB, once, then cached by your browser |
| Quality | Text becomes pixels |
| You get back | One image per page, zipped when the source has several |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Selectable text | Dropped | The target format has nowhere to put it. |
| Page layout | Kept | Carried through into the converted file. |
| Transparency | Dropped | The target format has nowhere to put it. |
Worth knowing before you start:
- pages render at twice their point size in opaque RGB, roughly 144 DPI, with no transparency
- reflowable input is laid out on a fixed 595x842pt page at 11pt before anything else happens
- the file passes through HTML on the way, so anything HTML cannot express does not survive
What is an FB2 file?#
An FB2 file is a single XML document that holds an entire book's text, metadata and base64-encoded cover images, in the FictionBook format that originated in the Russian-language ebook scene.
Keep a book as FB2 when it is sourced from a Russian-language ebook library and the reader is FB2-native, such as FBReader or a PocketBook device.
Convert FB2 to EPUB to read the book on a device or app outside the small set of readers that understand FictionBook directly.
What is an HDR file?#
An HDR file stores a high-dynamic-range raster image using Radiance's RGBE encoding, which packs red, green and blue mantissas with one shared exponent per pixel so a scene can hold a far wider range of brightness than a standard 8-bit image.
Reach for HDR when you need a compact high-dynamic-range environment map or lighting reference that most 3D tools and renderers can read without a plugin.
Convert HDR to OpenEXR when a VFX pipeline needs true floating-point precision, an alpha channel or multiple layers in one file, or convert it to JPEG or PNG once the image has been tone-mapped for a normal display.
FB2 to HDR questions people ask#
What is an FB2 file?
An FB2 file is an ebook in the FictionBook format, a single XML document that holds the full text, metadata and any cover image in one file rather than the zipped archive EPUB uses. It was created in 2004 and is most common in Russian-language ebook collections.
Can I open an FB2 file on a Kindle?
Not directly. Kindle devices do not read FB2, so the file needs converting to EPUB or MOBI first, either through Amazon's Send to Kindle pipeline or a separate converter.
What reader apps open FB2 files?
FBReader, Calibre, Okular and SumatraPDF all read FB2 files natively, and it is also the default format on many e-readers sold in Russian-language markets. Mainstream apps like Apple Books and the Kindle app do not.
What is an HDR file used for?
An HDR file most often stores an environment map or lighting reference for 3D rendering, since Radiance's RGBE encoding was built for the Radiance lighting-simulation software. Photographers also use the .hdr extension for panoramas merged from several exposures, before tone-mapping the result down to a normal image.