Image MIME Reference
IEF
Image Exchange Format
image/ief
VS
JPEG XR Image Sequence (HEIF Container)
image/jxrs
JPEG-XR-Sequence
A complete technical comparison of Image Exchange Format 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 | IEF | JPEG-XR-Sequence |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | ✕ No | Yes |
| Progressive Loading | ✕ No | Yes |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | ✕ No | Yes |
Image Exchange Format
image/ief
Extension
.ief
Container
TIFF Class B (TIFF-B)
Compression
Lossless (MH, MR, MMR) / Uncompressed
Algorithm
MHMRMMRUncompressed
Color Depth
1-bit (Monochrome)
Developed by
IETF Network Fax Working Group
Released
1992
Magic Bytes
49 49 2A 00 (Little-endian) / 4D 4D 00 2A (Big-endian)
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
Browser Support Comparison
| Browser | IEF | JPEG-XR-Sequence |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
IEF
IEF Strengths
- Provided a standard method for exchanging bi-level fax images during the early days of the Internet
- Supported multi-page documents
- Leveraged the highly resilient and well-documented TIFF container
Limitations
- Completely obsolete and unsupported in modern computing environments
- Strictly limited to 1-bit monochrome data, lacking color or grayscale capabilities
- Magic bytes overlap completely with standard TIFF, making specific filetype detection difficult without parsing internal tags
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
IEF
Use IEF when…
- Legacy Fax Transmissions
- Early Internet Gateways
- Archival
JPEG-XR-Sequence
Use JPEG-XR-Sequence when…
- Experimental Animation Workflows
- HDR Burst Photography Archiving
- Specialized Medical & Scientific Imaging