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Image MIME Reference
FITS

Flexible Image Transport System

image/fits
VS

JPEG XR Image Sequence (HEIF Container)

image/jxrs
JPEG-XR-Sequence

A complete technical comparison of Flexible Image Transport System and JPEG XR Image Sequence (HEIF Container) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature FITS JPEG-XR-Sequence
Transparency (Alpha) ✕ No Yes
Animation Support ✕ No Yes
Progressive Loading ✕ No Yes
HDR Support Yes Yes
EXIF Metadata ✕ No Yes
ICC Color Profile ✕ No Yes
Flexible Image Transport System
image/fits
Extension
.fits.fit.fts
Container FITS
Compression Uncompressed / Tile Compressed (Rice, GZIP)
Algorithm
UncompressedRiceGZIPHcompress
Color Depth 8-bit, 16-bit, 32-bit, 64-bit (Float/Double)
Developed by IAU FITS Working Group / NASA
Released 1981
Magic Bytes
53 49 4D 50 4C 45 20 20 3D 20
Full FITS reference →
JPEG XR Image Sequence (HEIF Container)
image/jxrs
Extension
.jxrs
Container HEIF / ISOBMFF (ISO/IEC 23008-12 / Annex F of ITU-T T.832)
Compression Lossy / Lossless
Algorithm
JPEG XR (Lapped Biorthogonal Transform)
Color Depth 8-bit, 16-bit, 32-bit (Float)
Developed by ISO/IEC JTC 1 / ITU-T
Released 2019
Magic Bytes
XX XX XX XX 66 74 79 70 6A 78 72 53
Full JPEG-XR-Sequence reference →

Browser Support Comparison

Browser FITS JPEG-XR-Sequence
Chrome Chrome
Firefox Firefox
Safari Safari
Edge Edge
IE IE (Legacy)
FITS

FITS Strengths

  • The undisputed global standard for archiving and sharing astronomical data
  • Self-documenting: Headers are written in plain ASCII, ensuring data is readable decades later regardless of software
  • Supports incredibly high dynamic range, N-dimensional arrays, and complex binary tables
Limitations
  • No support in standard consumer software or web browsers
  • Uncompressed raw FITS files from modern telescopes can be excessively large
  • Does not use standard metadata models like EXIF or XMP, requiring specialized parsers
JPEG-XR-Sequence

JPEG-XR-Sequence Strengths

  • Supports 32-bit floating point HDR color depths natively across an entire animation sequence
  • Combines the advanced coding efficiencies of JPEG XR with the sequence timing and metadata framework of HEIF
  • Shares frame data structures allowing for optimized storage of burst photography
Limitations
  • Extremely rare format with essentially no mainstream software adoption
  • Zero web browser support
  • Overshadowed heavily by HEVC (HEIC sequences) and AV1 (AVIF sequences) which offer superior compression and broader hardware decoding support

When to choose which format

FITS
Use FITS when…
  • Astronomy & Astrophysics
  • Space Telescope Data (Hubble, JWST)
  • Scientific Data Archiving
  • Spectroscopy
JPEG-XR-Sequence
Use JPEG-XR-Sequence when…
  • Experimental Animation Workflows
  • HDR Burst Photography Archiving
  • Specialized Medical & Scientific Imaging
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