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Image MIME Reference
HEIF-Sequence

High Efficiency Image File Format Sequence

image/heif-sequence
VS

JPEG 2000 Image (HEIF Container)

image/hej2k
HEJ2K

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

Equal browser support

Feature Support

Feature HEIF-Sequence HEJ2K
Transparency (Alpha) Yes Yes
Animation Support Yes ✕ No
Progressive Loading ✕ No Yes
HDR Support Yes Yes
EXIF Metadata Yes Yes
ICC Color Profile Yes Yes
High Efficiency Image File Format Sequence
image/heif-sequence
Extension
.heifs.heif.hif
Container HEIF / ISOBMFF (ISO/IEC 14496-12)
Compression Lossy / Lossless
Algorithm
Codec Agnostic (HEVC, AVC, JPEG, AV1)
Color Depth 8-bit, 10-bit, 12-bit, 16-bit
Developed by Moving Picture Experts Group (MPEG)
Released 2015
Magic Bytes
XX XX XX XX 66 74 79 70 6D 73 66 31
Full HEIF-Sequence reference →
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 →

Browser Support Comparison

Browser HEIF-Sequence HEJ2K
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
HEIF-Sequence

HEIF-Sequence Strengths

  • Codec-agnostic container allows for extreme flexibility when storing multi-frame photographic data
  • Maintains the space-saving benefits of ISOBMFF shared frame data blocks
  • Excellent for archiving computational photography workloads like exposure brackets or focal stacks
Limitations
  • Codec ambiguity means a decoder might be able to parse the container but fail to decode the underlying pixels
  • Zero native web browser support
  • Complex container structure requires specialized parsing libraries to extract individual frames
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

When to choose which format

HEIF-Sequence
Use HEIF-Sequence when…
  • Burst Photography
  • Focal Stacking
  • Exposure Bracketing
  • Time-Lapse Data
HEJ2K
Use HEJ2K when…
  • Medical Imaging
  • Geospatial Data
  • Scientific Archiving

More comparisons

HEIF-Sequence vs ACES → HEJ2K vs ACES → HEIF-Sequence vs APNG → HEJ2K vs APNG → HEIF-Sequence vs AVCI → HEJ2K vs AVCI → HEIF-Sequence vs AVCS → HEJ2K vs AVCS → HEIF-Sequence vs AVIF → HEJ2K vs AVIF → All comparisons →
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