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Image MIME Reference
HEJ2K

JPEG 2000 Image (HEIF Container)

image/hej2k
VS

Silicon Graphics Image

image/sgi
SGI

A complete technical comparison of JPEG 2000 Image (HEIF Container) and Silicon Graphics Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature HEJ2K SGI
Transparency (Alpha) Yes Yes
Animation Support ✕ No ✕ No
Progressive Loading Yes ✕ No
HDR Support Yes ✕ No
EXIF Metadata Yes ✕ No
ICC Color Profile Yes ✕ No
JPEG 2000 Image (HEIF Container)
image/hej2k
Extension
.hej2
Container HEIF / ISOBMFF (ISO/IEC 15444-16)
Compression Lossy / Lossless
Algorithm
JPEG 2000HTJ2K
Color Depth 8-bit, 10-bit, 12-bit, 16-bit
Developed by ISO/IEC JTC 1 / ITU-T
Released 2019
Magic Bytes
XX XX XX XX 66 74 79 70 6A 32 6B 69
Full HEJ2K reference →
Silicon Graphics Image
image/sgi
Extension
.sgi.rgb.rgba.bw.int.inta
Container SGI Image Format
Compression Uncompressed / Lossless (Run-Length Encoding)
Algorithm
RLENone
Color Depth 8-bit, 16-bit (Per Channel)
Developed by Paul Haeberli (Silicon Graphics)
Released 1990
Magic Bytes
01 DA
Full SGI reference →

Browser Support Comparison

Browser HEJ2K SGI
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
HEJ2K

HEJ2K Strengths

  • Brings the extensive capabilities of the HEIF container (like EXIF/XMP, thumbnails, and depth maps) to JPEG 2000
  • Supports mathematically lossless compression via wavelet transformation
  • High scalability and progressive decoding out of the box
Limitations
  • Extremely limited software support outside of niche industries
  • Zero native compatibility with web browsers
  • High computational complexity compared to simpler formats like JPEG or PNG
SGI

SGI Strengths

  • Pioneered multi-channel and 16-bit per channel imaging capabilities required for high-end 1990s visual effects
  • Extremely robust and simple header structure
  • Reliable Run-Length Encoding provided solid lossless compression for flat-shaded 3D renders
Limitations
  • Completely obsolete for modern web and application development
  • Zero native web browser compatibility
  • Largely replaced by TIFF and OpenEXR in modern professional VFX and 3D pipelines

When to choose which format

HEJ2K
Use HEJ2K when…
  • Medical Imaging
  • Geospatial Data
  • Scientific Archiving
SGI
Use SGI when…
  • Legacy 3D Animation & VFX
  • Silicon Graphics IRIX Workflows
  • Historical CGI Archiving

More comparisons

HEJ2K vs ACES → SGI vs ACES → HEJ2K vs APNG → SGI vs APNG → HEJ2K vs AVCI → SGI vs AVCI → HEJ2K vs AVCS → SGI vs AVCS → HEJ2K vs AVIF → SGI vs AVIF → All comparisons →
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