SNB to PFM Converter

SNB to PFM — free float map conversion online

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Floating-Point Precision

Convert SNB pages to PFM — 32-bit float-per-pixel precision that captures tonal range beyond what standard image formats can store.

Research-Grade Output

PFM is favored in scientific imaging and HDR photography. Your ebook pages get the precision that specialized tools demand.

Serverless for You

All processing happens on Convertio servers. No local software installation, no hardware demands on your end.

How to convert SNB to PFM

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose pfm or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your pfm file right afterwards

About formats

SNB is a proprietary ebook format developed by Shanghai Nutshell Electronics, a subsidiary of Shanda Interactive Entertainment, for the Bambook e-reader launched in August 2010. The format is structurally based on EPUB principles, packaging HTML content, CSS styling, images, and metadata within a compressed archive, but uses a proprietary container that restricts native playback to Bambook devices and associated software. Shanda designed the Bambook and its SNB ecosystem as an integrated reading platform tied to the Cloudary literature portal (later rebranded as China Literature), one of China's largest online publishing networks hosting millions of web novels and serialized fiction. The format supported reflowable text, chapter navigation, bookmarks, and basic typographic controls suited to Chinese-language content display. One advantage was tight integration with Shanda's massive content catalog, providing readers instant access to an enormous library of Chinese-language literature directly through the device. The Bambook was initially offered at a heavily subsidized price point, using the content ecosystem to drive revenue — a model that preceded similar strategies by other e-reader manufacturers. While the Bambook hardware line was eventually discontinued as the Chinese market shifted toward tablet-based reading apps, SNB files from that era can be converted to standard formats using tools like Calibre with appropriate plugins. The format represents an interesting case study in platform-specific ebook ecosystems within the Chinese digital publishing landscape.
Initial release: August 2010
PFM (Portable Float Map) is a floating-point raster image format devised by Paul Debevec around 2001, designed to store high-dynamic-range image data with the simplicity of the Netpbm family of formats. PFM extends the PBM/PGM/PPM philosophy — minimal header, raw data, no compression — to 32-bit IEEE floating-point samples, providing direct access to HDR pixel values without the encoding overhead of formats like OpenEXR or the limited range of Radiance HDR's RGBE encoding. The file structure is deliberately minimal: a two-character magic number ('Pf' for grayscale, 'PF' for color), width and height on the next line, a scale/endianness indicator (negative for little-endian, positive for big-endian, with magnitude indicating scale factor), and then the raw 32-bit float data for each pixel. PFM files store one float per pixel for grayscale or three floats (RGB) per pixel for color, with no compression, alpha channel, or metadata support. The format emerged from the HDR imaging research community where Debevec's work on image-based lighting and light stage capture required a simple, unambiguous way to store linear floating-point radiance values that could be easily exchanged between research tools. One advantage is absolute simplicity for HDR data: PFM can be read and written in a few lines of code in any language that supports IEEE floats, with no library dependencies — ideal for research prototyping and quick data exchange between custom tools. The format's widespread adoption in the computer vision and computational photography research community is another practical strength — optical flow benchmarks (Middlebury), depth estimation datasets, and radiance field captures commonly use PFM. The format is supported by ImageMagick, OpenCV, HDR Shop, and Luminance HDR.
Developer: Paul Debevec
Initial release: 2001

Frequently Asked Questions

Why convert SNB to PFM?

SNB is locked to Bambook devices. PFM stores floating-point pixel data — valuable for HDR workflows, research, and precision image analysis.

What reads PFM files?

GIMP, ImageMagick, Luminance HDR, various scientific imaging tools, and HDR-capable image editors support PFM format.

What is PFM?

PFM (Portable Float Map) extends the Netpbm family with 32-bit floating-point pixel values — far beyond standard 8-bit image precision.

Is PFM practical for ebook conversion?

PFM is specialized for high-precision imaging. For typical ebook viewing, simpler formats suffice, but PFM serves scientific needs well.

Is it free?

Yes, free SNB to PFM conversion is available on Convertio. Premium plans provide batch processing and higher limits.