Free webp to jpg
Image MIME Reference
HEIC-Sequence

HEVC Image Sequence (HEIF Container)

image/heic-sequence
VS

High-Throughput JPEG 2000 Image

image/jph
HTJ2K-(JPH)

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

HEIC-Sequence wins on browser support

Feature Support

Feature HEIC-Sequence HTJ2K-(JPH)
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
HEVC Image Sequence (HEIF Container)
image/heic-sequence
Extension
.heics.heic
Container HEIF / ISOBMFF (ISO/IEC 14496-12)
Compression Lossy / Lossless
Algorithm
HEVC (H.265)
Color Depth 8-bit, 10-bit, 12-bit, 16-bit
Developed by Moving Picture Experts Group (MPEG) / Apple
Released 2017
Magic Bytes
XX XX XX XX 66 74 79 70 68 65 76 63
Full HEIC-Sequence reference →
High-Throughput JPEG 2000 Image
image/jph
Extension
.jph
Container JPH (ISO/IEC 15444-15)
Compression Lossy / Lossless
Algorithm
High-Throughput JPEG 2000 (HTJ2K)
Color Depth 8-bit, 16-bit, 32-bit, 38-bit
Developed by Joint Photographic Experts Group (JPEG)
Released 2019
Magic Bytes
00 00 00 0C 6A 50 20 20 0D 0A 87 0A ... 66 74 79 70 6A 70 68 20
Full HTJ2K-(JPH) reference →

Browser Support Comparison

Browser HEIC-Sequence HTJ2K-(JPH)
Chrome Chrome
Firefox Firefox
Safari Safari
✓ 11+
Edge Edge
IE IE (Legacy)
HEIC-Sequence

HEIC-Sequence Strengths

  • Incredibly efficient storage for bursts and short animations compared to GIF or motion JPEG
  • Supports 16-bit color, HDR, and alpha channel transparency across all frames
  • Shares frame data blocks, meaning the base image and animation data are heavily optimized for space
Limitations
  • Zero support in web browsers outside the Apple ecosystem (Chrome, Firefox, Edge do not support it)
  • Heavily encumbered by HEVC patent pools, hindering open-source adoption
  • Complex container structure makes parsing and decoding difficult without specialized libraries
HTJ2K-(JPH)

HTJ2K-(JPH) Strengths

  • Delivers orders of magnitude faster encoding and decoding than standard JPEG 2000 by utilizing a new, parallelizable block coder
  • Supports mathematically lossless and lossy compression within the same codestream architecture
  • Allows for resolution scalability, progressive decoding, and region-of-interest extraction without needing to decode the entire image
Limitations
  • Zero native web browser support, requiring specialized libraries, API conversions, or WebAssembly (like OpenJPH.js) for web deployment
  • Lack of broad consumer awareness, keeping it confined to professional, medical, and scientific workflows
  • Requires more advanced software ecosystems to decode than ubiquitous formats like JPEG or WebP

When to choose which format

HEIC-Sequence
Use HEIC-Sequence when…
  • Apple Live Photos
  • Burst Photography
  • High-Quality Animations
  • Cinemagraphs
HTJ2K-(JPH)
Use HTJ2K-(JPH) when…
  • Medical Imaging (DICOM)
  • Geospatial Data
  • Digital Cinema
  • Professional Archiving
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