# What is a PFM File?

A Portable FloatMap file stores grayscale or RGB raster samples as floating-point values. Those samples can represent values outside the integer range commonly used for display images.

Encoded media + metadata

File format

Portable file

A file format defines how encoded content and metadata are organized for storage or exchange. This diagram shows file formats & compression broadly, not specifically PFM Files.

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## How PFM Files work

PFM arranges a small text header before an uncompressed stream of floating-point samples, with separate identifiers for single-channel and three-channel images. A signed scale field communicates byte order as well as a scale factor, so a reader must interpret it rather than treating the payload as native-endian data. In a media pipeline it is usually a working or interchange representation between numerical processing stages, not a final web or print asset.

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## Key facts

1. 1The header uses different magic identifiers for grayscale and RGB payloads, followed by dimensions and a scale value; there is no chunk directory or general metadata framework.
2. 2The sign of the scale value declares the payload’s byte order, while its magnitude is a scale factor. Ignoring either part can produce corrupted values or incorrect intensity.
3. 3PFM stores scanlines from the bottom upward under the common specification. A decoder that assumes the top-down order used by many raster formats will vertically flip the image.

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## When PFM Files matter

Choose PFM for intermediate computer-vision, depth, scientific, or high-dynamic-range data when floating-point precision matters. Limited application support and endianness handling can complicate interchange.

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## Common use cases for file formats & compression

These examples cover file formats & compression broadly, not specifically PFM Files.

* Accepting heterogeneous uploads while producing a controlled set of delivery formats.
* Moving assets between cameras, editors, browsers, archives, and downstream APIs.
* Separating long-lived source files from compact derivatives optimized for a particular channel.

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## Working with file formats & compression

This guidance covers file formats & compression broadly, not just PFM Files.

A parser reads the file structure, identifies contained streams and metadata, and exposes them to a decoder or application. Conversion usually decodes the source representation and writes compatible information into a different structure or encoding.

This category covers file and bitstream formats, their structures, and the compression methods they use. A filename extension can be misleading, so evaluate the detected format, decoding support, metadata, transparency, color, timing, patents, and archival needs before choosing an output.

### What you gain

* A suitable format preserves the properties a workflow actually needs.
* Standardized structures allow files to move between compatible tools and systems.
* Format conversion can improve delivery size, editability, or long-term accessibility.

### What it costs

* Modern formats can save bandwidth but may need fallbacks for older clients and production tools.
* Converting to a simpler format can discard transparency, animation, metadata, color precision, or editability.
* Archival suitability, browser support, and editing support often favor different choices.

### Before production

1. 1Inspect the detected container, codec, MIME type, and magic bytes instead of trusting a suffix.
2. 2Verify decoder support and preserve metadata, color, transparency, or timing when required.
3. 3Retain the source when the chosen delivery format is lossy or tied to current software.

[← Per-Title Encoding](/glossary/per-title-encoding.md)[PGF File →](/glossary/pgf-file.md)

More in file formats & compression

* [Next-Gen Formats](/glossary/next-gen-formats.md)
* [PBM File](/glossary/pbm-file.md)
* [PDF](/glossary/pdf.md)
* [PGF File](/glossary/pgf-file.md)
* [PGM File](/glossary/pgm-file.md)
* [PJPEG](/glossary/pjpeg.md)

[All 505 terms](/glossary.md)

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